Use of Galois Automorphisms in Homomorphic Encryption

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to ethereum [link] [comments]

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to privacycoins [link] [comments]

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to CryptoCurrencies [link] [comments]

The Privacy Coin Guide Part 1

As interest picks up in crypto again, I want to share this post I made on privacy coins again to just give the basics of their evolution. This is only part 1, and parts 2 and 3 are not available in this format, but this part is informative and basic.
If you’re looking for a quick and easy way to assess what the best privacy coin in the current space is, which has the best features, or which is most likely to give high returns, then this is not that guide. My goal is to give you the power to make your own decisions, to clearly state my biases, and educate. I really wanted to understand this niche of the crypto-space due to my background and current loyalties[1], and grasp the nuances of the features, origins and timelines of technologies used in privacy coins, while not being anything close to a developer myself. This is going to be a 3-part series, starting with an overview and basic review of the technology, then looking at its implications, and ending with why I like a specific project. It might be mildly interesting or delightfully educational. Cryptocurrencies are young and existing privacy coins are deploying technology that is a work in progress. This series assumes a basic understanding of how blockchains work, specifically as used in cryptocurrencies. If you don’t have that understanding, might I suggest that you get it? [2],[3],[4] Because cryptocurrencies have a long way to go before reaching their end-game: when the world relies on the technology without understanding it. So, shall we do a deep dive into the privacy coin space?

FIRST THERE WAS BITCOIN

Cryptocurrencies allow you to tokenize value and track its exchange between hands over time, with transaction information verified by a distributed network of users. The most famous version of a cryptocurrency in use is Bitcoin, defined as peer-to-peer electronic cash. [5] Posted anonymously in 2008, the whitepaper seemed to be in direct response to the global financial meltdown and public distrust of the conventional banking and financing systems. Although cryptographic techniques are used in Bitcoin to ensure that (i) only the owner of a specific wallet has the authority to spend funds from that wallet, (ii) the public address is linked but cannot be traced by a third party to the private address (iii) the information is stored via cryptographic hashing in a merkle tree structure to ensure data integrity, the actual transaction information is publicly visible on the blockchain and can be traced back to the individual through chain analysis.[6] This has raised fears of possible financial censorship or the metaphorical tainting of money due to its origination point, as demonstrated in the Silk Road marketplace disaster.[7] This can happen because fiat money is usually exchanged for cryptocurrency at some point, as crypto-enthusiasts are born in the real world and inevitably cash out. There are already chain analysis firms and software that are increasingly efficient at tracking transactions on the Bitcoin blockchain.[8] This lack of privacy is one of the limitations of Bitcoin that has resulted in the creation of altcoins that experiment with the different features a cryptocurrency can have. Privacy coins are figuring out how to introduce privacy in addition to the payment network. The goal is to make the cryptocurrency fungible, each unit able to be exchanged for equal value without knowledge of its transaction history – like cash, while being publicly verifiable on a decentralized network. In other words, anyone can add the math up without being able to see the full details. Some privacy solutions and protocols have popped up as a result:

CRYPTONOTE – RING SIGNATURES AND STEALTH ADDRESSES

Used in: Monero and Particl as its successor RING-CT, Bytecoin
In December 2012, CryptoNote introduced the use of ring signatures and stealth addresses (along with other notable features such as its own codebase) to improve cryptocurrency privacy.[9] An updated CryptoNote version 2 came in October 2013 [10](though there is some dispute over this timeline [11]), also authored under the name Nicolas van Saberhagen. Ring signatures hide sender information by having the sender sign a transaction using a signature that could belong to multiple users. This makes a transaction untraceable. Stealth addresses allow a receiver to give a single address which generates a different public address for funds to be received at each time funds are sent to it. That makes a transaction unlinkable. In terms of privacy, CryptoNote gave us a protocol for untraceable and unlinkable transactions. The first implementation of CryptoNote technology was Bytecoin in March 2014 (timeline disputed [12]), which spawned many children (forks) in subsequent years, a notable example being Monero, based on CryptoNote v2 in April 2014.
RING SIGNATURES and STEALTH ADDRESSES

PROS

– Provides sender and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume
-Does not hide transaction information if not combined with another protocol.

COINJOIN

Used in: Dash
Bitcoin developer Gregory Maxwell proposed a set of solutions to bring privacy to Bitcoin and cryptocurrencies, the first being CoinJoin (January 28 – Aug 22, 2013).[13],[14] CoinJoin (sometimes called CoinSwap) allows multiple users to combine their transactions into a single transaction, by receiving inputs from multiple users, and then sending their outputs to the multiple users, irrespective of who in the group the inputs came from. So, the receiver will get whatever output amount they were supposed to, but it cannot be directly traced to its origination input. Similar proposals include Coinshuffle in 2014 and Tumblebit in 2016, building on CoinJoin but not terribly popular [15],[16]. They fixed the need for a trusted third party to ‘mix’ the transactions. There are CoinJoin implementations that are being actively worked on but are not the most popular privacy solutions of today. A notable coin that uses CoinJoin technology is Dash, launched in January 2014, with masternodes in place of a trusted party.
COINJOIN

PROS

– Provides sender and receiver privacy
– Easy to implement on any cryptocurrency
– Lightweight
– Greater scalability with bulletproofs
– Mature technology

CONS

– Least anonymous privacy solution. Transaction amounts can be calculated
– Even without third-party mixer, depends on wealth centralization of masternodes

ZEROCOIN

Used in: Zcoin, PIVX
In May 2013, the Zerocoin protocol was introduced by John Hopkins University professor Matthew D. Green and his graduate students Ian Miers and Christina Garman.[17] In response to the need for use of a third party to do CoinJoin, the Zerocoin proposal allowed for a coin to be destroyed and remade in order to erase its history whenever it is spent. Zero-knowledge cryptography and zero-knowledge proofs are used to prove that the new coins for spending are being appropriately made. A zero-knowledge proof allows one party to prove to another that they know specific information, without revealing any information about it, other than the fact that they know it. Zerocoin was not accepted by the Bitcoin community as an implementation to be added to Bitcoin, so a new cryptocurrency had to be formed. Zcoin was the first cryptocurrency to implement the Zerocoin protocol in 2016. [18]
ZEROCOIN

PROS

– Provides sender and receiver privacy
– Supply can be audited
– Relatively mature technology
– Does not require a third-party

CONS

– Requires trusted setup (May not be required with Sigma protocol)
– Large proof sizes (not lightweight)
– Does not provide full privacy for transaction amounts

ZEROCASH

Used in: Zcash, Horizen, Komodo, Zclassic, Bitcoin Private
In May 2014, the current successor to the Zerocoin protocol, Zerocash, was created, also by Matthew Green and others (Eli Ben-Sasson, Alessandro Chiesa, Christina Garman, Matthew Green, Ian Miers, Eran Tromer, Madars Virza).[19] It improved upon the Zerocoin concept by taking advantage of zero-knowledge proofs called zk-snarks (zero knowledge succinct non-interactive arguments of knowledge). Unlike Zerocoin, which hid coin origins and payment history, Zerocash was faster, with smaller transaction sizes, and hides transaction information on the sender, receiver and amount. Zcash is the first cryptocurrency to implement the Zerocash protocol in 2016. [20]
ZEROCASH

PROS

– Provides full anonymity. Sender, receiver and amount hidden.
– Privacy can be default?
– Fast due to small proof sizes.
– Payment amount can be optionally disclosed for auditing
– Does not require any third-party

CONS

– Requires trusted setup. (May be improved with zt-starks technology)
– Supply cannot be audited. And coins can potentially be forged without proper implementation.
– Private transactions computationally intensive (improved with Sapling upgrade)

CONFIDENTIAL TRANSACTIONS

Used in: Monero and Particl with Ring Signatures as RING-CT
The next proposal from Maxwell was that of confidential transactions, proposed in June 2015 as part of the Sidechain Elements project from Blockstream, where Maxwell was Chief Technical Officer.[21],[22] It proposed to hide the transaction amount and asset type (e.g. deposits, currencies, shares), so that only the sender and receiver are aware of the amount, unless they choose to make the amount public. It uses homomorphic encryption[23] to encrypt the inputs and outputs by using blinding factors and a kind of ring signature in a commitment scheme, so the amount can be ‘committed’ to, without the amount actually being known. I’m terribly sorry if you now have the urge to go and research exactly what that means. The takeaway is that the transaction amount can be hidden from outsiders while being verifiable.
CONFIDENTIAL TRANSACTIONS

PROS

– Hides transaction amounts
– Privacy can be default
– Mature technology
– Does not require any third-party

CONS

– Only provides transaction amount privacy when used alone

RING-CT

Used in: Monero, Particl
Then came Ring Confidential transactions, proposed by Shen-Noether of Monero Research Labs in October 2015.[24] RingCT combines the use of ring signatures for hiding sender information, with the use of confidential transactions (which also uses ring signatures) for hiding amounts. The proposal described a new type of ring signature, A Multi-layered Linkable Spontaneous Anonymous Group signature which “allows for hidden amounts, origins and destinations of transactions with reasonable efficiency and verifiable, trustless coin generation”.[25] RingCT was implemented in Monero in January 2017 and made mandatory after September 2017.
RING -CONFIDENTIAL TRANSACTIONS

PROS

– Provides full anonymity. Hides transaction amounts and receiver privacy
– Privacy can be default
– Mature technology
– Greater scalability with bulletproofs
– Does not require any third-party

CONS

– Privacy not very effective without high volume

MIMBLEWIMBLE

Used in: Grin
Mimblewimble was proposed in July 2016 by pseudonymous contributor Tom Elvis Jedusorand further developed in October 2016 by Andrew Poelstra.[26],[27] Mimblewimble is a “privacy and fungibility focused cryptocoin transaction structure proposal”.[28] The key words are transaction structure proposal, so the way the blockchain is built is different, in order to accommodate privacy and fungibility features. Mimblewimble uses the concept of Confidential transactions to keep amounts hidden, looks at private keys and transaction information to prove ownership of funds rather than using addresses, and bundles transactions together instead of listing them separately on the blockchain. It also introduces a novel method of pruning the blockchain. Grin is a cryptocurrency in development that is applying Mimblewimble. Mimblewimble is early in development and you can understand it more here [29].
MIMBLEWIMBLE

PROS

– Hides transaction amounts and receiver privacy
– Privacy is on by default
– Lightweight
– No public addresses?

CONS

– Privacy not very effective without high volume
– Sender and receiver must both be online
– Relatively new technology

ZEXE

Fresh off the minds of brilliant cryptographers (Sean Bowe, Alessandro Chiesa, Matthew Green, Ian Miers, Pratyush Mishra, Howard Wu), in October 2018 Zexe proposed a new cryptographic primitive called ‘decentralized private computation.[30] It allows users of a decentralized ledger to “execute offline computations that result in transactions”[31], but also keeps transaction amounts hidden and allows transaction validation to happen at any time regardless of computations being done online. This can have far reaching implications for privacy coins in the future. Consider cases where transactions need to be automatic and private, without both parties being present.

NETWORK PRIVACY

Privacy technologies that look at network privacy as nodes communicate with each other on the network are important considerations, rather than just looking at privacy on the blockchain itself. Anonymous layers encrypt and/or reroute data as it moves among peers, so it is not obvious who they originate from on the network. They are used to protect against surveillance or censorship from ISPs and governments. The Invisible Internet Project (I2P) is an anonymous network layer that uses end to end encryption for peers on a network to communicate with each other.[32] Its history dates back to 2003. Kovri is a Monero created implementation of I2P.[33] The Onion Router (Tor) is another anonymity layer [34]) that Verge is a privacy cryptocurrency that uses. But its historical link to the US government may be is concerning to some[35]. Dandelion transaction relay is also an upcoming Bitcoin improvement proposal (BIP) that scrambles IP data that will provide network privacy for Bitcoin as transaction and other information is transmitted.[36],[37],[38]

UPCOMING

Monero completed bulletproofs protocol updates that reduce RINGCT transaction sizes and thus transaction fee costs. (Bulletproofs are a replacement for range proofs used in confidential transactions that aid in encrypting inputs and outputs by making sure they add to zero).
Sigma Protocol – being actively researched by Zcoin team as of 2018 to replace Zerocoin protocol so that a trusted setup is not required.[39] There is a possible replacement for zk-snarks, called zk-starks, another form of zero-knowledge proof technology, that may make a trusted set-up unnecessary for zero-knowledege proof coins.[40]

PART 1 CONCLUSION OF THE PRIVACY COIN GUIDE ON THE TECHNOLOGY BEHIND PRIVACY COINS

Although Bitcoin is still a groundbreaking technology that gives us a trust-less transaction system, it has failed to live up to its expectations of privacy. Over time, new privacy technologies have arrived and are arriving with innovative and exciting solutions for Bitcoin’s lack of fungibility. It is important to note that these technologies are built on prior research and application, but we are considering their use in cryptocurrencies. Protocols are proposed based on cryptographic concepts that show how they would work, and then developers actually implement them. Please note that I did not include the possibility of improper implementation as a disadvantage, and the advantages assume that the technical development is well done. A very important point is that coins can also adapt new privacy technologies as their merits become obvious, even as they start with a specific privacy protocol. Furthermore, I am, unfortunately, positive that this is not an exhaustive overview and I am only covering publicized solutions. Next, we’ll talk more about the pros and cons and give an idea of how the coins can be compared.

There's a video version that can be watched, and you can find out how to get the second two parts if you want on my website (video link on the page): https://cryptoramble.com/guide-on-privacy-coins/
submitted by CryptoRamble to ethtrader [link] [comments]

If mathematicians find a way to make Homomorphic Crypto work at practical speed, then privacy can be proven without trust

https://en.wikipedia.org/wiki/Homomorphic_encryption
Its the next level above end-to-end-encryption. It doesnt require ends, but if it has them, they can not be proven to exist, and there can be anywhere between 0 and infinity ends and even create and remove ends while its still encrypted.
The internet works by encrypting info between certain pairs of computers but on those computers themselves its not encrypted. Homomorphic encryption closes that security hole by keeping it encrypted both on computers and between them and it can keep computing to more and more computers (if people choose to run the homomorphic crypted programs) without any of them being able to know what they are computing. There doesnt need to be any trust across the whole internet to collaborate among billions of people and computers.
End-to-end encryption is not good enough. That just means between the computers. For example, if you send bitcoins using your computer, there might be a hacker who has access to your computer who can steal your wallet.dat file and use it himself. With homomorphic crypto, even the bitcoin program and wallet.dat would be encrypted to the extent that someone could not even detect that you are using bitcoin, and even if they knew exactly which part of the computers memory bitcoin is supposedly in and which other computers its interacting with across the internet, they still could not detect that its bitcoin running instead of some other peer to peer program. Instead, it is possible to, for example on pen and paper, calculate a number that you type into the "bitcoin running on your computer in homomorphic encrypted form" that tells it you are commanding it to move your money, or have another computer do that, in a whole web of computers that none of them can know what themself or others are doing while they are doing it. Practically, instead of using pen and paper, this means you dont have to trust apps to do the things they say they will or to keep your data private.
You could for example give facebook your personal data which facebook would be able to use for certain purposes but could not figure out what your personal data is. There would never be another large scale email apologizing for leaking your data from various websites, since they wouldnt have it but could still compute in turing-complete ways things with it.
submitted by BenRayfield to KeepOurNetFree [link] [comments]

Technical: Upcoming Improvements to Lightning Network

Price? Who gives a shit about price when Lightning Network development is a lot more interesting?????
One thing about LN is that because there's no need for consensus before implementing things, figuring out the status of things is quite a bit more difficult than on Bitcoin. In one hand it lets larger groups of people work on improving LN faster without having to coordinate so much. On the other hand it leads to some fragmentation of the LN space, with compatibility problems occasionally coming up.
The below is just a smattering sample of LN stuff I personally find interesting. There's a bunch of other stuff, like splice and dual-funding, that I won't cover --- post is long enough as-is, and besides, some of the below aren't as well-known.
Anyway.....

"eltoo" Decker-Russell-Osuntokun

Yeah the exciting new Lightning Network channel update protocol!

Advantages

Myths

Disadvantages

Multipart payments / AMP

Splitting up large payments into smaller parts!

Details

Advantages

Disadvantages

Payment points / scalars

Using the magic of elliptic curve homomorphism for fun and Lightning Network profits!
Basically, currently on Lightning an invoice has a payment hash, and the receiver reveals a payment preimage which, when inputted to SHA256, returns the given payment hash.
Instead of using payment hashes and preimages, just replace them with payment points and scalars. An invoice will now contain a payment point, and the receiver reveals a payment scalar (private key) which, when multiplied with the standard generator point G on secp256k1, returns the given payment point.
This is basically Scriptless Script usage on Lightning, instead of HTLCs we have Scriptless Script Pointlocked Timelocked Contracts (PTLCs).

Advantages

Disadvantages

Pay-for-data

Ensuring that payers cannot access data or other digital goods without proof of having paid the provider.
In a nutshell: the payment preimage used as a proof-of-payment is the decryption key of the data. The provider gives the encrypted data, and issues an invoice. The buyer of the data then has to pay over Lightning in order to learn the decryption key, with the decryption key being the payment preimage.

Advantages

Disadvantages

Stuckless payments

No more payments getting stuck somewhere in the Lightning network without knowing whether the payee will ever get paid!
(that's actually a bit overmuch claim, payments still can get stuck, but what "stuckless" really enables is that we can now safely run another parallel payment attempt until any one of the payment attempts get through).
Basically, by using the ability to add points together, the payer can enforce that the payee can only claim the funds if it knows two pieces of information:
  1. The payment scalar corresponding to the payment point in the invoice signed by the payee.
  2. An "acknowledgment" scalar provided by the payer to the payee via another communication path.
This allows the payer to make multiple payment attempts in parallel, unlike the current situation where we must wait for an attempt to fail before trying another route. The payer only needs to ensure it generates different acknowledgment scalars for each payment attempt.
Then, if at least one of the payment attempts reaches the payee, the payee can then acquire the acknowledgment scalar from the payer. Then the payee can acquire the payment. If the payee attempts to acquire multiple acknowledgment scalars for the same payment, the payer just gives out one and then tells the payee "LOL don't try to scam me", so the payee can only acquire a single acknowledgment scalar, meaning it can only claim a payment once; it can't claim multiple parallel payments.

Advantages

Disadvantages

Non-custodial escrow over Lightning

The "acknowledgment" scalar used in stuckless can be reused here.
The acknowledgment scalar is derived as an ECDH shared secret between the payer and the escrow service. On arrival of payment to the payee, the payee queries the escrow to determine if the acknowledgment point is from a scalar that the escrow can derive using ECDH with the payer, plus a hash of the contract terms of the trade (for example, to transfer some goods in exchange for Lightning payment). Once the payee gets confirmation from the escrow that the acknowledgment scalar is known by the escrow, the payee performs the trade, then asks the payer to provide the acknowledgment scalar once the trade completes.
If the payer refuses to give the acknowledgment scalar even though the payee has given over the goods to be traded, then the payee contacts the escrow again, reveals the contract terms text, and requests to be paid. If the escrow finds in favor of the payee (i.e. it determines the goods have arrived at the payer as per the contract text) then it gives the acknowledgment scalar to the payee.

Advantages

Disadvantages

Payment decorrelation

Because elliptic curve points can be added (unlike hashes), for every forwarding node, we an add a "blinding" point / scalar. This prevents multiple forwarding nodes from discovering that they have been on the same payment route. This is unlike the current payment hash + preimage, where the same hash is used along the route.
In fact, the acknowledgment scalar we use in stuckless and escrow can simply be the sum of each blinding scalar used at each forwarding node.

Advantages

Disadvantages

submitted by almkglor to Bitcoin [link] [comments]

Threshold Signature Explained— Bringing Exciting Applications with TSS

Threshold Signature Explained— Bringing Exciting Applications with TSS
— A deep dive into threshold signature without mathematics by ARPA’s cryptographer Dr. Alex Su

https://preview.redd.it/cp0wib2mk0q41.png?width=757&format=png&auto=webp&s=d42056f42fb16041bc512f10f10fed56a16dc279
Threshold signature is a distributed multi-party signature protocol that includes distributed key generation, signature, and verification algorithms.
In recent years, with the rapid development of blockchain technology, signature algorithms have gained widespread attention in both academic research and real-world applications. Its properties like security, practicability, scalability, and decentralization of signature are pored through.
Due to the fact that blockchain and signature are closely connected, the development of signature algorithms and the introduction of new signature paradigms will directly affect the characteristics and efficiency of blockchain networks.
In addition, institutional and personal account key management requirements stimulated by distributed ledgers have also spawned many wallet applications, and this change has also affected traditional enterprises. No matter in the blockchain or traditional financial institutions, the threshold signature scheme can bring security and privacy improvement in various scenarios. As an emerging technology, threshold signatures are still under academic research and discussions, among which there are unverified security risks and practical problems.
This article will start from the technical rationale and discuss about cryptography and blockchain. Then we will compare multi-party computation and threshold signature before discussing the pros and cons of different paradigms of signature. In the end, there will be a list of use cases of threshold signature. So that, the reader may quickly learn about the threshold signature.
I. Cryptography in Daily Life
Before introducing threshold signatures, let’s get a general understanding of cryptography. How does cryptography protect digital information? How to create an identity in the digital world? At the very beginning, people want secure storage and transmission. After one creates a key, he can use symmetric encryption to store secrets. If two people have the same key, they can achieve secure transmission between them. Like, the king encrypts a command and the general decrypts it with the corresponding key.
But when two people do not have a safe channel to use, how can they create a shared key? So, the key exchange protocol came into being. Analogously, if the king issues an order to all the people in the digital world, how can everyone proves that the sentence originated from the king? As such, the digital signature protocol was invented. Both protocols are based on public key cryptography, or asymmetric cryptographic algorithms.


“Tiger Rune” is a troop deployment tool used by ancient emperor’s, made of bronze or gold tokens in the shape of a tiger, split in half, half of which is given to the general and the other half is saved by the emperor. Only when two tiger amulets are combined and used at the same time, will the amulet holder get the right to dispatch troops.
Symmetric and asymmetric encryption constitute the main components of modern cryptography. They both have three fixed parts: key generation, encryption, and decryption. Here, we focus on digital signature protocols. The key generation process generates a pair of associated keys: the public key and the private key. The public key is open to everyone, and the private key represents the identity and is only revealed to the owner. Whoever owns the private key has the identity represented by the key. The encryption algorithm, or signature algorithm, takes the private key as input and generate a signature on a piece of information. The decryption algorithm, or signature verification algorithm, uses public keys to verify the validity of the signature and the correctness of the information.
II. Signature in the Blockchain
Looking back on blockchain, it uses consensus algorithm to construct distributed books, and signature provides identity information for blockchain. All the transaction information on the blockchain is identified by the signature of the transaction initiator. The blockchain can verify the signature according to specific rules to check the transaction validity, all thanks to the immutability and verifiability of the signature.
For cryptography, the blockchain is more than using signature protocol, or that the consensus algorithm based on Proof-of-Work uses a hash function. Blockchain builds an infrastructure layer of consensus and transaction through. On top of that, the novel cryptographic protocols such as secure multi-party computation, zero-knowledge proof, homomorphic encryption thrives. For example, secure multi-party computation, which is naturally adapted to distributed networks, can build secure data transfer and machine learning platforms on the blockchain. The special nature of zero-knowledge proof provides feasibility for verifiable anonymous transactions. The combination of these cutting-edge cryptographic protocols and blockchain technology will drive the development of the digital world in the next decade, leading to secure data sharing, privacy protection, or more applications now unimaginable.
III. Secure Multi-party Computation and Threshold Signature
After introducing how digital signature protocol affects our lives, and how to help the blockchain build identities and record transactions, we will mention secure multi-party computation (MPC), from where we can see how threshold signatures achieve decentralization. For more about MPC, please refer to our previous posts which detailed the technical background and application scenarios.
MPC, by definition, is a secure computation that several participants jointly execute. Security here means that, in one computation, all participants provide their own private input, and can obtain results from the calculation. It is not possible to get any private information entered by other parties. In 1982, when Prof. Yao proposed the concept of MPC, he gave an example called the “Millionaires Problem” — two millionaires who want to know who is richer than the other without telling the true amount of assets. Specifically, the secure multiparty computation would care about the following properties:
  • Privacy: Any participant cannot obtain any private input of other participants, except for information that can be inferred from the computation results.
  • Correctness and verifiability: The computation should ensure correct execution, and the legitimacy and correctness of this process should be verifiable by participants or third parties.
  • Fairness or robustness: All parties involved in the calculation, if not agreed in advance, should be able to obtain the computation results at the same time or cannot obtain the results.
Supposing we use secure multi-party computation to make a digital signature in a general sense, we will proceed as follows:
  • Key generation phase: all future participants will be involved together to do two things: 1) each involved party generates a secret private key; 2) The public key is calculated according to the sequence of private keys.
  • Signature phase: Participants joining in a certain signature use their own private keys as private inputs, and the information to be signed as a public input to perform a joint signature operation to obtain a signature. In this process, the privacy of secure multi-party computing ensures the security of private keys. The correctness and robustness guarantee the unforgeability of the signature and everyone can all get signatures.
  • Verification phase: Use the public key corresponding to the transaction to verify the signature as traditional algorithm. There is no “secret input” during the verification, this means that the verification can be performed without multi-party computation, which will become an advantage of multi-party computation type distributed signature.
The signature protocol constructed on the idea of ​​secure multiparty computing is the threshold signature. It should be noted that we have omitted some details, because secure multiparty computing is actually a collective name for a type of cryptographic protocol. For different security assumptions and threshold settings, there are different construction methods. Therefore, the threshold signatures of different settings will also have distinctive properties, this article will not explain each setting, but the comparative result with other signature schemes will be introduced in the next section.
IV. Single Signature, Multi-Signature and Threshold Signature
Besides the threshold signature, what other methods can we choose?
Bitcoin at the beginning, uses single signature which allocates each account with one private key. The message signed by this key is considered legitimate. Later, in order to avoid single point of failure, or introduce account management by multiple people, Bitcoin provides a multi-signature function. Multi-signature can be simply understood as each account owner signs successively and post all signatures to the chain. Then signatures are verified in order on the chain. When certain conditions are met, the transaction is legitimate. This method achieves a multiple private keys control purpose.
So, what’s the difference between multi-signature and threshold signature?
Several constraints of multi-signature are:
  1. The access structure is not flexible. If an account’s access structure is given, that is, which private keys can complete a legal signature, this structure cannot be adjusted at a later stage. For example, a participant withdraws, or a new involved party needs to change the access structure. If you must change, you need to complete the initial setup process again, which will change the public key and account address as well.
  2. Less efficiency. The first is that the verification on chain consumes power of all nodes, and therefore requires a processing fee. The verification of multiple signatures is equivalent to multiple single signatures. The second is performance. The verification obviously takes more time.
  3. Requirements of smart contract support and algorithm adaptation that varies from chain to chain. Because multi-sig is not naturally supported. Due to the possible vulnerabilities in smart contracts, this support is considered risky.
  4. No anonymity, this is not able to be trivially called disadvantage or advantage, because anonymity is required for specific conditions. Anonymity here means that multi-signature directly exposes all participating signers of the transaction.
Correspondingly, the threshold signature has the following features:
  1. The access structure is flexible. Through an additional multi-party computation, the existing private key sequence can be expanded to assign private keys to new participants. This process will not expose the old and newly generated private key, nor will it change the public key and account address.
  2. It provides more efficiency. For the chain, the signature generated by the threshold signature is not different from a single signature, which means the following improvements : a) The verification is the same as the single signature, and needs no additional fee; b ) the information of the signer is invisible, because for other nodes, the information is decrypted with the same public key; c) No smart contract on chain is needed to provide additional support.
In addition to the above discussion, there is a distributed signature scheme supported by Shamir secret sharing. Secret sharing algorithm has a long history which is used to slice information storage and perform error correction information. From the underlying algorithm of secure computation to the error correction of the disc. This technology has always played an important role, but the main problem is that when used in a signature protocol, Shamir secret sharing needs to recover the master private key.
As for multiple signatures or threshold signature, the master private key has never been reconstructed, even if it is in memory or cache. this short-term reconstruction is not tolerable for vital accounts.
V. Limitations
Just like other secure multi-party computation protocols, the introduction of other participants makes security model different with traditional point-to-point encrypted transmission. The problem of conspiracy and malicious participants were not taken into account in algorithms before. The behavior of physical entities cannot be restricted, and perpetrators are introduced into participating groups.
Therefore, multi-party cryptographic protocols cannot obtain the security strength as before. Effort is needed to develop threshold signature applications, integrate existing infrastructure, and test the true strength of threshold signature scheme.
VI. Scenarios
1. Key Management
The use of threshold signature in key management system can achieve a more flexible administration, such as ARPA’s enterprise key management API. One can use the access structure to design authorization pattern for users with different priorities. In addition, for the entry of new entities, the threshold signature can quickly refresh the key. This operation can also be performed periodically to level up the difficulty of hacking multiple private keys at the same time. Finally, for the verifier, the threshold signature is not different from the traditional signature, so it is compatible with old equipments and reduces the update cost. ARPA enterprise key management modules already support Elliptic Curve Digital Signature Scheme secp256k1 and ed25519 parameters. In the future, it will be compatible with more parameters.

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2. Crypto Wallet
Wallets based on threshold signature are more secure because the private key doesn’t need to be rebuilt. Also, without all signatures posted publicly, anonymity can be achieved. Compared to the multi-signature, threshold signature needs less transaction fees. Similar to key management applications, the administration of digital asset accounts can also be more flexible. Furthermore, threshold signature wallet can support various blockchains that do not natively support multi-signature, which reduces the risk of smart contracts bugs.

Conclusion

This article describes why people need the threshold signature, and what inspiring properties it may bring. One can see that threshold signature has higher security, more flexible control, more efficient verification process. In fact, different signature technologies have different application scenarios, such as aggregate signatures not mentioned in the article, and BLS-based multi-signature. At the same time, readers are also welcomed to read more about secure multi-party computation. Secure computation is the holy grail of cryptographic protocols. It can accomplish much more than the application of threshold signatures. In the near future, secure computation will solve more specific application questions in the digital world.

About Author

Dr. Alex Su works for ARPA as the cryptography researcher. He got his Bachelor’s degree in Electronic Engineering and Ph.D. in Cryptography from Tsinghua University. Dr. Su’s research interests include multi-party computation and post-quantum cryptography implementation and acceleration.

About ARPA

ARPA is committed to providing secure data transfer solutions based on cryptographic operations for businesses and individuals.
The ARPA secure multi-party computing network can be used as a protocol layer to implement privacy computing capabilities for public chains, and it enables developers to build efficient, secure, and data-protected business applications on private smart contracts. Enterprise and personal data can, therefore, be analyzed securely on the ARPA computing network without fear of exposing the data to any third party.
ARPA’s multi-party computing technology supports secure data markets, precision marketing, credit score calculations, and even the safe realization of personal data.
ARPA’s core team is international, with PhDs in cryptography from Tsinghua University, experienced systems engineers from Google, Uber, Amazon, Huawei and Mitsubishi, blockchain experts from the University of Tokyo, AIG, and the World Bank. We also have hired data scientists from CircleUp, as well as financial and data professionals from Fosun and Fidelity Investments.
For more information about ARPA, or to join our team, please contact us at [email protected].
Learn about ARPA’s recent official news:
Telegram (English): https://t.me/arpa_community
Telegram (Việt Nam): https://t.me/ARPAVietnam
Telegram (Russian): https://t.me/arpa_community_ru
Telegram (Indonesian): https://t.me/Arpa_Indonesia
Telegram (Thai): https://t.me/Arpa_Thai
Telegram (Philippines):https://t.me/ARPA_Philippines
Telegram (Turkish): https://t.me/Arpa_Turkey
Korean Chats: https://open.kakao.com/o/giExbhmb (Kakao) & https://t.me/arpakoreanofficial (Telegram, new)
Medium: https://medium.com/@arpa
Twitter: u/arpaofficial
Reddit: https://www.reddit.com/arpachain/
Facebook: https://www.facebook.com/ARPA-317434982266680/54
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Celare: “Safe deposit box” for data and assets, protecting privacy and security

Celare: “Safe deposit box” for data and assets, protecting privacy and security

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Privacy security is a growing problem.
On March 19, the sale of 538 million users’ data from Weibo in the form of bitcoin on the Deep Web has raised the issue of privacy security again.
The 36kr analyzed the process for the leak of personal information on Weibo. Hackers upload fake mobile phone address books in batches through the relevant interface of Weibo to match the friend’s account information,then he can match the identity information of the user account successfully.
In fact, with the development of technology, the problem of personal information leakage tends to be more and more dangerous. Even if you take precautions, personal information can become part of the thousands of messages that hackers sell.
With the arrival of the information era, data has become a resource that many businesses compete for, which has given rise to a series of privacy security problems and also spawned a series of gray industrial chains. The privacy of users has gradually become a commodity with a precise price tag. Facebook, Microsoft, Apple, and other global giants have all been exposed for collecting users’ privacy, which still happens.
Data networks can help people to a better life. Still, a series of data privacy problem is to violate the rights and interests of users, such as data leakage by people they know and privacy exposure. The protection of privacy and security has become an urgent issue, but in the centralized system, how to use the data depends on the controller’s preference, and the user never has the dominant right.
Decentralized blockchain is now becoming a better solution to privacy and security problems.
Celare anonymous technology solutions created by blockchain will effectively guarantee the privacy security of users.
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Anonymity is safety
How to ensure the privacy of users? The answer is anonymity.
There are many projects with anonymous technology in the blockchain.
Whether it is the Zero-Knowledge proof mechanism of ZCash, the CoinJoin Scheme of Dash, or the Ring confidential transaction mechanism of XMR, it can ensure the anonymity of transactions to a certain extent and guarantee the users privacy and security.
Celare also uses anonymity to protect users’ privacy. It is the first cross-chain anonymous privacy solution of all digital assets on Polkadot ecology, which is based on blockchain decentralization. Celare has designed a new anonymous mechanism,Non-interactive Zero Knowledge Proof,based on the existing technology. Compared with zero-knowledge proof, the non-interactive system has a more reliable anonymous function, which can completely solve the problem of transaction tracking and protect user privacy.
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When choosing the zk-SNARK Zero-Knowledge proof curve, Celare chose BLS12–381 curve with a higher security coefficient, which is higher than that of BN128, to guarantee Celare’s top privacy and anonymity.
The method of zero-knowledge proof in practical application is as follows:
When the user registers, the identity information is stored on the server in the form of digital commitment. In the process of identity authentication, the user authenticates himself to the server as a member of the registered user by using the member proof scheme, to avoid the user presenting his identity information to the server every time he logs in.
It is just one fundamental part of Celare’s efforts to protect users’ privacy.
Celare also adds a fully homomorphic encryption scheme in the chain, which can perform arbitrary calculations on the ciphertext without decryption. It is just one of the basics of Celare’s efforts to protect users’ privacy. Full homomorphic encryption can perform arbitrary calculations on the ciphertext without decryption. So the problem of data privacy security can be solved quickly without losing computability.
The comprehensive security technology system is one aspect of Celare protection of user privacy. Besides, Celare uses authorization technology to truly realize that the user is the master of the data, allowing users to control their data freely.
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Safe and efficient
Safety is only the first step.
What Celare seeks is safety and efficiency.
As is known to all, the three anonymous tokens, Dash, XMR, ZEC, are still used in the field of payment and cannot be further expanded. The reason is that the system does not support smart contracts. And scalability is too low for large-scale commercial use, especially at the data interaction level.
To avoid the limits of anonymous cryptocurrency and better promote the anonymous technology into a broader field, Celare innovative introduced intelligent contracts into its system, which significantly improved Celare efficiency and laid a good foundation for its large-scale commercial use.
Since Celare is a public chain developed based on Polkadot Substrate, it follows Polkadot’s PoS consensus algorithm and contract technology. To maintain the speed and efficiency of data transmission on the chain, Celare will establish a large-scale PoS node network capable of supporting nearly a thousand consensus nodes, infinitely reducing the block out time and ultimately determining the delay time of it.
The high TPS brought by large-scale nodes will provide a technical guarantee for Celare’s widespread application. It also means each transaction of users can be conducted at high speed under the anonymous environment, which not only ensures users’ privacy security but also enables them to enjoy the free experience and indeed promotes the implementation of blockchain technology.
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Break the information isolated island, link multiple public chains
Security and efficiency are only part of the Celare blockchain infrastructure. Also, Celare has built a cross-chain technology to interconnect multiple public chains.
For a long time, information cannot be transferred, and digital assets cannot be traded between each public chain, which significantly limits the application space of blockchain. Cross-chain technology came into being, among which Polkadot is the outstanding one.
Celare cross-chain technology also relies on Polkadot. Its internal logic is that the user locks the assets on the original chain and then issues the mapped assets on the target chain. At the same time, the user can apply for a withdrawal on the target chain and unlock the original one.
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Celare cross-chain technology will further protect users’ privacy and security, which means users can quickly transfer their data and digital assets from other chains to the Celare chain. It helps users consolidate all the data on different chains into a Celare account for easy management. With the help of Celare privacy protection technology, the security of users’ private data is truly guaranteed.
Since the establishment of the project, Celare’s mission has always been to protect users’ privacy and security. Therefore, Celare makes various development and further expansion to better service and privacy and ensure users’ privacy and security.
In the future, Celare will break the barrier of cross-chain assets and truly protect user privacy and anonymity.
Contact Us:
Twitter: @CelareCommunity
Telegram: Celare Community
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RenVM AMA Answers

RenVM AMA Answers


1) What are some challenges you think will come up in 2020?
Some of the biggest challenges that we see for 2020 are:
Adoption; it is the most difficult, but it has the highest impact for the project, and for the blockchain community at large. Perhaps the biggest challenge within adoption is education. It is critical that people understand how RenVM works, its capabilities, its limitations, where it is meant to be used, and where it is not meant to be used. At times, it has already proved difficult to cut through misinformation/misunderstanding that proliferates throughout the wider community or to explain complex cryptographic concepts. We will be addressing these challenges by producing more education material, releasing audits (when they’re completed), engaging more with other communities, and open-sourcing more of the project.
Rolling out updates; to the Darknodes as fixes, improvements, and new features. This is a technical challenge, but also a social challenge. It requires comprehensive testing environments and a focus on backwards compatibility, but it also requires coordination and social agreement amongst hundreds (and potentially thousands) of Darknode owners. To face these challenges, we have already begun building more extensive testing frameworks, auto-update capabilities for the Darknodes, and looking at informal methods of governance (until we settle on a formal one).

2) As far as I understand, you already have a list of companies that will be the first to adopt RenVM and make integration. How do these companies feel about the fact that not all repositories are open and some of the code is still closed (private repo)? Doesn't that scare them off? Do you have plans to go full open source?
TL:DR: Yes, absolutely we plan going full open-source and all projects we are in conversation with are aware of the below plan and understand the logic behind it. Our logic and subsequent plan (and the thresholds needed) to go full open-source can be found in this document, if curious: RenVM Open-Source Roadmap.
Long Answer: The team at Ren are very strong proponents of the open-source ethos and believe all decentralized protocols need to be made open-source when secure. The Ren team also wants to (a) be competitive in this space, given the hard work and capital invested by the team and the community, and (b) give an appropriate amount of time for security issues to be discovered and fixed before making the codebase available to potentially malicious actors.
With that said, all of Ren's codebase barring the RZL sMPC algorithm will be open-sourced at the advent of RenVM Mainnet Subzero which will be launched after our security audit is completed. The RZL sMPC algorithm, however, is what makes RenVM and its sMPC solution so special. This RZL sMPC Algorithm has been pioneered in-house by our development team and can be considered a trade secret. It will, therefore, not be released to the wider public until certain security and capital thresholds within RenVM have been met. We have worked very hard over the last two years; this approach ensures RenVM's security and that the Ren community, team, and investors are rewarded for their patience.
Stage 1 | Q1 2020 RenVM Mainnet Security Audit
The security audit will verify our RZL sMPC algorithm security, correctness, and functionality under a Non-Disclosure Agreement (NDA). This, the security audit of RenVM, and all other components of RenVM's code-base will be available for the public to review when completed.
Stage 2 | Q2 2020 Onward
Our RZL sMPC Algorithm will be fully open-sourced to the public when the milestones outlined in this document are met: https://github.com/renproject/ren/issues/2
This document has purposefully been designed for open comment as we encourage any stakeholder to voice their opinion or suggestions (supported by empirically-based evidence, of course). The team will take the feedback and incorporate them into the RenVM Open-Source Roadmap thresholds.
The open comment period will end at the formal release of RenVM Mainnet Subzero, at which point the specific security and capital thresholds will be solidified, and presented to the public. If you have suggestions or questions, please do voice them on our Github! https://github.com/renproject/ren/issues/2

3) Any ideas on which DeFi dapps could or should in your opinion use RenVM?
Any DeFi app can utilize RenVM. If their users have a desire to trade/lend cross-chain pairs then they could/should use RenVM to do so. With that said, a few potential use cases can be found below:
  1. Cross-Chain Decentralized Exchanges,
  2. Cross-Chain Lending & Leveraging,
  3. Multi-Collateralized Synthetics and Stablecoins (e.g. DAI),
  4. No-Counterparty Risk OTC Desk | An Interoperable Escrow,
  5. Multi-Collateral Crowdfunding,
  6. Multi-Collateral Basketed Investment vehicle (ETFs),
  7. Universal Cross-Chain Stablecoin Converter.
We’ll also be releasing a blog that outlines all the potential use cases for RenVM in the coming months, so please do stay tuned!

4) Have you announced a partnership with AZTEC, what are your plans for cooperation with them, are these plans still in force or have your priorities changed?
At this stage, our entire focus is on Mainnet SubZero. But, we will definitely be following up on integrating with AZTEC once everything is released, stable, and adopted.

5) Can you expand on Universal Interoperability and how important of a role it will play in the future, what are the qualifications of being that third party?
TL:DR: The ultimate goal of Universal Interoperability is to ensure a great user experience (UX) regardless of what Blockchain they come from or its end destination. In the immediate terms, this means abstracting away confirmation wait times and the need for ETH gas, so someone could use a BTC on a DeFi app (built on Ethereum) and never know it.
Long Answer: The number and speed of confirmations inherently depends on the original chain and must be set at the time the chain is admitted into the protocol. RenVM mainnet will wait for 6 confirmations for BTC (Chaosnet, is 2). This obviously takes a long time and, while it’s not so bad for some use cases (lending, collateralization, etc), it’s not the best for dApps/DEXs and general UX. ‌ So, we have the concept of Universal Interoperability which allows a third party to provide two things (in exchange for a fee nominated by users):
1) Expedited Confirmations | Confirmation as a Service (CaaS)
CaaS= Expedited Confirmations | This removes confirmations wait time for users when minting digital assets on Ethereum. It provides speed by taking on the confirmation risk. The third-party sees you have (let’s say) 1 confirmation and is confident you’re not a miner about to attack Bitcoin. They come in and provide the shifted BTC immediately to complete whatever action you were taking, and when the real underlying shift finishes the 3rd party get their funds back.
By implementing CaaS, developers can help users complete actions faster by using funds that have already been shifted. These funds can be accessed in a variety of trustful and trustless ways, however the goal is the same - facilitate a cross-chain transaction in a shorter time than it would take the user to first fully shift in an asset (i.e. for BTC, RenVM waits for six (6) confirmations).
2) GSN Integration | Gas as a Service (GaaS)
GaaS = GSN Integration | This removes the need for users to interact with ETH gas when dealing with native blockchain interactions. It provides gas so you don’t need to manage lots of different tokens, just the ones you’re actually using for the dApp.By Implementing GaaS, this allows dApps to pay for their users' transactions in a secure way, so users don’t need to hold ETH to pay for their gas or even set up an account. This can be particularly valuable when it comes to cross-chain applications as you might be building for a non-ethereum user base.
*We'll be releasing a demo if these working the real-world quite soon along with tutorials for 3rd parties to use these solutions if they so choose.

6) What’s the path forward for more liquidity on the REN token? Currently US users are limited in where they can purchase tokens and cannot easily acquire enough to get bonding for even one Darknode.
We encourage those who are restricted based on their jurisdiction to utilize the decentralized exchange infrastructure currently available. We try to practice what we preach and by utilizing DeFi, it's a great way to further propel the space into the mainstream.
We can’t legally recommend specific exchanges and we don't publicly discuss potentially listing until they are public, but do know we are always working on bringing more democratic access to REN.

7) How does your company plan to make money in the future (to finance the development, when the money received on the ICO will be over)?
Our team’s incentives are directly aligned with that of our community (those who run Darknodes). The organization and its funding is centered around Darknode rewards. Darknodes earn fees for facilitating interoperability via RenVM and this is how the organization will fund itself.

8) How does the audit go, any major issue has been identified that could delay MN subzero? When is it estimated to complete an audit?
The audit is going well. The smart contracts have been finished, and all issues were addressed quickly. The Hyperdrive audit is currently underway, and there have been no critical issues reported so far. The next steps are to scope the audit for the RZL sMPC paper and its accompanying implementation (the z0 engine). There are no timeline estimates that we are comfortable giving to the public at this stage, as audits times can vary a lot depending on what is found, and an audit of an sMPC implementation is not common (estimates quickly propagate through the community and become incorrectly interpreted as hard commitments).

9) How does your sMPC algorithm work? Can't find any description anywhere. Can the Darknodes perform any calculations over any data splitted using SSS? How fast are those calculations performed? How is the new private key generated for the next era, so old nodes that generated this key does not have access to it? Also, What kind of help from external developers do you need right now?
- It takes many pages of very formal discussion to describe how our sMPC algorithm works, but we are working on a paper that formally defines the algorithm, and proves its properties. This paper is being audited, and both the paper and audit will be released to the public after the release of Mainnet.- Darknodes can, in theory, perform any computation over Shamir secret shared (SSS) data, but they are only configured to perform interoperability related computation at the moment (key generation, and key signing).
- The performance of general computation over SSS data is very dependent on the kind of computation, however, sMPC is invariably orders of magnitude slower than the equivalent computations running on your local machine (because they involve network communication).
- Every epoch a new key must be generated to store assets (and assets in the old key must be transferred to this new key). The old group of Darknodes can generate the new key in such a way that the public key is known, but the private key shares are encrypted for the new group of Darknodes (this process does not reveal any of the new shares to any of the old Darknodes). Under the hood, this uses very simple homomorphic properties. Once the new key is generated, the old Darknodes can simply do their usual sMPC to transfer all assets to the new key.
-We would love it if the developer community started experimenting with our SDKs and contributed their thoughts/improvement to RenVM (and the dev infrastructure that supports it e.g. RenJS & GatewayJS) via: https://github.com/renproject/ren/issues

10) What are the plans for the initial network bootstrapping to onboard darknodes to achieve sufficient decentralization and deliver on the security benefits? I understand the early stages of the network will have the core nodes of the Ren Team and trusted partners responsible for maintaining the integrity of the network - do you intend to remain in this phase until sufficient transaction volume is on the network that attracts sufficient 3rd party operators? Are there plans to incentive that initial volume?
We intend to remain in the Mainnet SubZero phase until there is sufficient volume (stable over a reasonable period of time) to attract members of the public to run Darknodes and earn rewards by doing so. During this period, Ren and other projects will operate Darknodes to keep the networking running (and to keep it semi-decentralized amongst Ren and these third-parties). It is important for the security of the network that volume grows naturally, otherwise, it risks dropping after the incentivization ends. However, to begin with, we will support volume by providing liquidity to DEXs, and keeping minting fees low.

Thank everyone for contributing to our first AMA!
We'll have more over the coming months but as always, if you have any questions just come and ask in our Telegram: https://t.me/renproject
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Bottos 2020 Research and Development Scheme

Bottos 2020 Research and Development Scheme

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As 2020 is now here, Bottos has solemnly released its “2020 Research and development scheme”. On one hand, we adhere to the principle of transparency so that the whole community can comprehend our next step as a whole, but more importantly, it also helps our whole team to think deeply about the future and reach consensus. It is strongly believed that following these consistent follow-ups will help us to in order to achieve the best results.
Based on the efficient development of Bottos, the team’s technical achievements in consensus algorithms and smart contracts are used to deeply implement and optimize the existing technical architecture. At the same time using the community’s technical capabilities, horizontal development, expanding new functional modules and technical directions it stays closely integrated with the whole community.
In the future, we will keep on striving to achieve in-depth thinking, comprehensive planning, and flexible adjustment.


Overview of Technical Routes

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User feedback within the community is the driving force behind Bottos progress. In the development route of the community and industry we have formulated a roadmap for technical development, pointing out the right path for the team towards the right direction among the massive routes of modern technology.
As part of our 2020 research and development objective we have the following arrangements:
1. Intensifying enormous number of smart contracts and related infrastructures
After many years of development, smart contracts have gradually become the core and standard function in blockchain projects. The strength of smart contracts, ease of use, and stability represent the key capabilities of a blockchain project. As a good start, Bottos has already made great progress in the field of smart contracts. In smart contracts we still need to increase development efforts, making the ease of use and stability of smart contracts the top priority of our future development.
Reducing the barriers for developers and ordinary users to use, shortening the contract development cycle and saving users time is another important task for the team to accomplish. To this end, we have planned an efficient and easy-to-use one-stop contract development, debugging, and deployment tool that will provide multiple access methods and interfaces to the test network to support rapid deployment and rapid debugging.
2. Establishing an excellent client and user portal
The main goal here is to add an entrance point to the creation and deployment of smart contracts in the wallet client. To this end, the wallet needs to be transformed, a local compiler for smart contracts must be added, and an easy-to-use UI interface can be provided for the purpose of creating, deploying, and managing contracts to meet the needs of users with a single mouse click only.
3. Expanding distributed storage
Distributed storage is another focus of our development in the upcoming year. Only by using a distributed architecture can completely solve the issue of performance and scalability of stand-alone storage. Distributed storage suitable for blockchain needs to provide no less than single machine performance, extremely high availability, no single point of failure, easy expansion, and strong consistent transactions. These are the main key points and difficulties of Bottos in field of distributed storage in the upcoming days.
4. Reinforcing multi party secured computing
Privacy in computing is also a very important branch to deal with. In this research direction, Bottos has invested a lot of time and produced many research results on multi-party secured computing, such as technical articles and test cases. In the future, we will continue to give efforts in the direction of multi-party secured computing and apply mature technology achievements into the functions of the chain.

2020 Bottos — Product Development

Support for smart contract deployment in wallets
The built-in smart contract compiler inside the wallet supports compilation of the smart contracts in all languages provided by Bottos and integrates with the functions in the wallet. It also supports one-click deployment of the compiled contract source code in the wallet.
When compiling a contract, one can choose whether to pre-execute the contract code. If pre-execution is selected, it will connect to the remote contract pre-execution service and return the execution result to the wallet.
When deploying a contract, one can choose to deploy to the test network or main network and the corresponding account and private key of the test network or main network should be provided.

2020 Bottos-Technical Research

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1. Intelligent smart contract development platform (BISDP)
The smart contract development platform BISDP is mainly composed of user-oriented interfaces, as well as back-end compilation and deployment tools, debugging tools, and pre-execution frameworks.
The user-oriented interface provides access methods based on WEB, PC, and mobile apps, allowing developers to quickly and easily compile and deploy contracts and provide contract template management functions. It can also manage the contract remotely by viewing the contract execution status, the consumed resources and other information.
In the compilation and deployment tool a set of smart contract source code editing, running, debugging, and deployment solutions as well as smart contract templates for common tasks are provided, which greatly reduces the threshold for developers to learn and use smart contracts. At the same time, developers and ordinary users are provided with a smart contract pre-execution framework, which can check the logical defects and security risks in smart contracts before actual deployment and promptly remind users a series of problems even before the smart contracts are actually run.
In the debugging tool, there are built-in local debugging and remote debugging tools. Multiple breakpoints can be set in the debugging tool. When the code reaches the breakpoint, one can view the variables and their contents in the current execution stack. One can also make conditional breakpoints based on the value of the variable. The code will not execute until the value reaches a preset value in memory.
In the pre-execution framework, developers can choose to pre-execute contract code in a virtual environment or a test net, checking out problems in some code that cannot be detected during compilation time and perform deeper code inspection. The pre-execution framework can also prompt the user in advance about the time and space resources required for execution.
2. Supporting Python and PHP in BVM virtual machine for writing smart contracts
We have added smart contract writing tools based on Python and PHP languages. These languages can be compiled into the corresponding BVM instruction set for implementation. These two reasons are used as the programming language for smart contracts.
For the Python language, the basic language elements supported by the first phase are:
- Logic control: If, Else, Eli, While, Break, method calls, for x in y
- Arithmetic and relational operators: ADD, SUB, MUL, DIV, ABS, LSHIFT, RSHIFT, AND, OR, XOR, MODULE, INVERT, GT, GTE, LT, LTE, EQ, NOTEQ
-
Data structure:
- Supports creation, addition, deletion, replacement, and calculation of length of list data structure
- Supports creation, append, delete, replace, and calculation of length of dict data structure
Function: Supports function definition and function calls
For the PHP language, the basic language elements supported by the first phase are :
- Logic control: If, Else, Eli, While, Break, method calls
- Arithmetic and relational operators: ADD, SUB, MUL, DIV, ABS, LSHIFT, RSHIFT, AND, OR, XOR, MODULE, INVERT, GT, GTE, LT, LTE, EQ, NOTEQ
Data structure:
- Support for creating, appending, deleting, replacing, and calculating length of associative arrays
Function: Supports the definition and calling of functions
For these two above mentioned languages, the syntax highlighting and code hinting functions are also provided in BISDP, which is very convenient for developers to debug any errors.
3. Continuous exploration of distributed storage solutions
Distributed storage in blockchain technology actually refers to a distributed database. Compared with the traditional DMBS, in addition to the ACID characteristics of the traditional DBMS, the distributed database also provides the high availability and horizontal expansion of the distributed system. The CAP principle of distributed system reveals that for a common distributed system there is an impossible triangle, only two of them can be selected among its three directions, consistency, availability, and partition fault tolerance. Distributed databases in China must require strong consistency. This is due to the characteristics of the blockchain system itself, because it needs to provide reliable distributed transaction capabilities. For these technical issues, before ensuring that the distributed storage solution reaches 100% availability, we will continue to invest more time and technical strength, do more functional and performance testing, and conduct targeted tests for distributed storage systems.
4. Boosting secured multi-party computing research and development
Secured multi-party Computing (MPC) is a cryptographic mechanism that enables multiple entities to share data while protecting the confidentiality of the data without exposing the secret encryption key. Its performance indicators, such as security and reliability are important for the realization of the blockchain. The transparent sharing of the data privacy on the distributed ledger and the privacy protection of the client wallet’s private key are truly essential.
At present, the research and development status of the platform provided by Bottos in terms of privacy-enhanced secured multi-party computing is based on the BIP32 / 44 standard in Bitcoin wallets to implement distributed management of client wallet keys and privacy protection.
Considering the higher level of data security and the distributed blockchain account as the public data of each node, further research and development are being planned on:
(1) Based on RSA, Pailliar, ECDSA and other public key cryptosystems with homomorphic attributes, as well as the GC protocol, OT protocol, and ZKP protocol to generate and verify transaction signatures between two parties;
(2) Introduce the international mainstream public key system with higher security and performance, national secret public key encryption system, and fewer or non-interactive ZKP protocols to achieve secured multi-party computing with more than two parties, allowing more nodes to participate Privacy protection of ledger data.

Summary

After years of exploration, we are now full of confidence in our current research and development direction. We are totally determined to move forward by continuous hard work. In the end, all members of Bottos also want to thank all the friends in the community for their continuous support and outstanding contributions. Your certainty is our greatest comfort and strongest motivation.

Be smart. Be data-driven. Be Bottos.
If you aren’t already in our group, please join now! https://t.me/bottosofficial
Join Our Community and Stay Updated!
Bottos Website | Twitter |Facebook | Telegram | Reddit
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AMA with Wanchain VP Lini

AMA with Wanchain VP Lini
Original article here: https://medium.com/wanchain-foundation/ama-with-wanchain-vp-lini-58ada078b4fe

“What is unique about us is that we have actually put theory into practice.”
— Lini
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Wanchain’s Vice President of Business Development, Lini, sat down with blockchain media organization Neutrino for an AMA covering a wide range of topics concerning Wanchain’s development.
The following is an English translation of the original Chinese AMA which was held on December 13th, 2018:
Neutrino: Could you please first share with us a little basic background, what are the basic concepts behind cross chain technology? What are the core problems which are solved with cross-chain? In your opinion, what is the biggest challenge of implementing cross chain to achieve value transfer between different chains?
Lini: Actually, this question is quite big. Let me break it down into three smaller parts:
  1. First, what is the meaning of “cross-chain”?
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In China, we like to use the word “cross-chain”, the term “interoperability” is used more frequently in foreign countries. Interoperability is also one of the important technologies identified by Vitalik for the development of a future blockchain ecosystem mentioned in the Ethereum white paper. So cross-chain is basically the concept of interoperability between chains.
  1. The core problem solved by cross chain is that of “multi-ledger” synchronous accounting
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In essence, blockchain is a distributed bookkeeping technique, also known as distributed ledger technology. Tokens are the core units of account on each chain, there currently exist many different chains, each with their own token. Of especial importance is the way in which each ledger uses tokens to interact with each other for the purpose of clearing settlements.
  1. The core purpose of the cross-chain technology is as one of the key infrastructures of the future economy based on digital currencies.
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Cross chain technology is one of the foundational technological infrastructures that is necessary for the large scale application of blockchain technology.
Neutrino: As we all know, there are many different kinds of cross-chain technologies. Please give us a brief introduction to several popular cross-chain technologies on the market, and the characteristics of each of these technologies。
Lini: Before answering this question, it is very important to share two important concepts with our friends: heterogeneity and homogeneity, and centralization and decentralization.
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These two points are especially important for understanding various cross-chain technologies, because there are many different technologies and terminologies, and these are some of the foundational concepts needed for understanding them.
There are also two core challenges which must be overcome to implement cross-chain:
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Combining the above two points, we look at the exploration of some solutions in the industry and the design concepts of other cross-chain projects.
First I’d like to discuss the Relay solution.
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However the Relay solution must consume a relatively large amount of gas to read the BTC header. Another downside is that, as we all know, Bitcoin’s blocks are relatively slow, so the time to wait for verification will be long, it usually takes about 10 minutes to wait for one block to confirm, and the best practice is to wait for 6 blocks.
The next concept is the idea of Sidechains.
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This solution is good, but not all chains contain SPV, a simple verification method. Therefore, there are certain drawbacks. Of course, this two way peg way solves challenge beta very well, that is, the atomicity of the transaction.
These two technical concepts have already been incorporated into a number of existing cross chain projects. Let’s take a look at two of the most influential of these.
The first is Polkadot.
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This is just a summary based on Polkadot’s whitepaper and most recent developments. The theoretical design is very good and can solve challenges alpha and beta. Last week, Neutrino organized a meetup with Polkadot, which we attended. In his talk, Gavin’s focus was on governance, he didn’t get into too much technical detail, but Gavin shared some very interesting ideas about chain governance mechanisms! The specific technical details of Polkadot may have to wait until after their main net is online before it can be analyzed.
Next is Cosmos.
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Cosmos is a star project who’s basic concept is similar to Polkadot. Cosmos’s approach is based on using a central hub. Both projects both take into account the issue of heterogeneous cross-chain transactions, and both have also taken into account how to solve challenges alpha and beta.
To sum up, each research and project team has done a lot of exploration on the best methods for implementing cross-chain technology, but many are still in the theoretical design stage. Unfortunately, since the main net has not launched yet, it is not possible to have a more detailed understanding of each project’s implementation. A blockchain’s development can be divided into two parts: theoretical design, and engineering implementation. Therefore, we can only wait until after the launch of each project’s main network, and then analyze it in more detail.
Neutrino: As mentioned in the white paper, Wanchain is a general ledger based on Ethereum, with the goal of building a distributed digital asset financial infrastructure. There are a few questions related to this. How do you solve Ethereum’s scaling problem? How does it compare with Ripple, which is aiming to be the standard trading protocol that is common to all major banks around the world? As a basic potential fundamental financial infrastructure, what makes Wanchain stand out?
Lini: This question is actually composed of two small questions. Let me answer the first one first.
  1. Considerations about TPS.
First of all, Wanchain is not developed on Ethereum. Instead, it draws on some of Ethereum’s code and excellent smart contracts and virtual machine EVM and other mature technical solutions to build the mainnet of Wanchain.
The TPS of Ethereum is not high at this stage, which is limited by various factors such as the POW consensus mechanism. However, this point also in part is due to the characteristics of Ethereum’s very distributed and decentralized features. Therefore, in order to improve TPS, Wanchain stated in its whitepaper that it will launch its own POS consensus, thus partially solving the performance issues related to TPS. Wanchain’s POS is completely different from the POS mechanism of Ethereum 2.0 Casper.
Of course, at the same time, we are also paying close attention to many good proposals from the Ethereum community, such as sharding, state channels, side chains, and the Raiden network. Since blockchain exists in the world of open source, we can of course learn from other technological breakthroughs and use our own POS to further improve TPS. If we have some time at the end, I’d love to share some points about Wanchain’s POS mechanism.
  1. Concerning, Ripple, it is completely different from what Wanchain hopes to do.
Ripple is focused on exchanges between different fiat pairs, the sharing of data between banks and financial institutions, as a clearing and settlement system, and also for the application of DLT, for example the Notary agent mechanism.
Wanchain is focused on different use cases, it is to act as a bridge between different tokens and tokens, and between assets and tokens. For various cross-chain applications it is necessary to consume WAN as a gas fee to pay out to nodes.
So it seems that the purpose Ripple and Wanchain serve are quite different. Of course, there are notary witnesses in the cross-chain mechanism, that is, everyone must trust the middleman. Ripple mainly serves financial clients, banks, so essentially everyone’s trust is already there.
Neutrino: We see that Wanchain uses a multi-party computing and threshold key sharing scheme for joint anchoring, and achieves “minimum cost” for integration through cross-chain communication protocols without changing the original chain mechanism. What are the technical characteristics of multi-party computing and threshold key sharing? How do other chains access Wanchain, what is the cross-chain communication protocol here? What is the cost of “minimum cost?
Lini: The answer to this question is more technical, involving a lot of cryptography, I will try to explain it in a simple way.
  1. About sMPC -
It stands for secure multi-party computation. I will explain it using an example proposed by the scholar Andrew Yao, the only Turing Award winner in China. The scenario called Yao’s Millionaire Problem. How can two millionaires know who is wealthier without revealing the details of their wealth to each other or a trusted third party? I’m not going to explain the answer in detail here, but those who are interested can do a web search to learn more.
In sMPC multiple parties each holding their own piece of private data jointly perform a calculation (for example, calculating a maximum value) and obtain a calculation result. However, in the process, each party involved does not leak any of their respective data. Essentially sMPC calculation can allow for designing a protocol without relying on any trusted third parties, since no individual ever has access to the complete private information.
Secure multiparty computing can be abstractly understood as two parties who each have their own private data, and can calculate the results of a public function without leaking their private data. When the entire calculation is completed, only the calculation results are revealed to both parties, and neither of them knows the data of the other party and the intermediate data of the calculation process. The protocol used for secure multiparty computing is homomorphic encryption + secret sharing + OT (+ commitment scheme + zero knowledge proofs, etc.)
Wanchain’s 21 cross chain Storeman nodes use sMPC to participate in the verification of a transaction without obtaining of a user’s complete private key. Simply put, the user’s private key will have 21 pieces given to 21 anonymous people who each can only get 1/21 part, and can’t complete the whole key.
  1. Shamir’s secret sharing
There are often plots in a movie where a top secret document needs to be handed over to, let’s say five secret agents. In order to protect against the chance of an agent from being arrested or betraying the rest, the five agents each hold only part of a secret key which will reveal the contents of the documents. But there is also a hidden danger: if one the agents are really caught, how can the rest of the agents access the information in the documents? At this point, you may wonder if there is any way for the agents to still recover the original text with only a portion of the keys? In other words, is there any method that allows a majority of the five people to be present to unlock the top secret documents? In this case, the enemy must be able to manipulate more than half of the agents to know the information in the secret documents.
Wanchain uses the threshold M<=N; N=21; M=16. That is to say, at least 16 Storeman nodes must participate in multi-party calculation to confirm a transaction. Not all 21 Storeman nodes are required to participate. This is a solution to the security problem of managing private keys.
Cross-chain communication protocols refers to the different communication methods used by different chains. This is because heterogeneous cross-chain methods can’t change the mechanism of the original chains. Nakamoto and Vitalik will not modify their main chains because they need BTC and ETH interoperability. Therefore, project teams that can only do cross-chain agreements to create different protocols for each chain to “talk”, or communicate. So the essence of a cross-chain protocol is not a single standard, but a multiple sets of standards. But there is still a shared sMPC and threshold design with the Storeman nodes.
The minimum cost is quite low, as can be shown with Wanchain 3.0’s cross chain implementation. In fact it requires just two smart contracts, one each on Ethereum and Wanchain to connect the two chains. To connect with Bitcoin all that is needed is to write a Bitcoin script. Our implementation guarantees both security and decentralization, while at the same time remaining simple and consuming less computation. The specific Ethereum contract and Bitcoin scripts online can be checked out by anyone interested in learning more.
Neutrino: What kind of consensus mechanism is currently used by Wanchain? In addition, what is the consensus and incentive mechanism for cross-chain transactions, and what is the purpose of doing so? And Wanchain will support cross-chain transactions (such as BTC, ETH) on mainstream public chains, asset cross-chain transactions between the alliance chains, and cross-chain transactions between the public and alliance chains, how can you achieve asset cross-chain security and privacy?
Lini: It is now PPOW (Permissioned Proof of Work), in order to ensure the reliability of the nodes before the cross-chain protocol design is completed, and to prepare to switch to POS (as according to the Whitepaper roadmap). The cross-chain consensus has been mentioned above, with the participation of a small consensus (at least 16 nodes) in a set of 21 Storeman nodes through sMPC and threshold secret sharing.
In addition, the incentive is achieved through two aspects: 1) 100% of the cross chain transaction fee is used to reward the Storeman node; 2) Wanchain has set aside a portion of their total token reserve as an incentive mechanism for encouraging Storeman nodes in case of small cross-chain transaction volume in the beginning.
It can be revealed that Storeman participation is opening gradually and will become completely distributed and decentralized in batches. The first phase of the Storeman node participation and rewards program is to be launched at the end of 2018. It is expected that the selection of participants will be completed within one quarter. Please pay attention to our official announcements this month.
In addition, for public chains, consortium chains, and private chains, asset transfer will also follow the cross-chain mechanism mentioned above, and generally follow the sMPC and threshold integration technology to ensure cross-chain security.
When it comes to privacy, this topic will be bigger. Going back to the Wanchain Whitepaper, we have provided privacy protection on Wanchain mainnet. Simply put, the principle is using ring signatures. The basic idea is that it mixes the original address with many other addresses to ensure privacy. We also use one-time address. In this mechanism a stamp system is used that generates a one-time address from a common address. This has been implemented since our 2.0 release.
But now only the privacy protection of native WAN transactions can be provided. The protection of cross-chain privacy and user experience will also be one of the important tasks for us in 2019.
Neutrino: At present, Wanchain uses Storeman as a cross-chain trading node. Can you introduce the Storeman mechanism and how to protect these nodes?
Lini: Let me one problem from two aspects.
  1. As I introduced before in my explanation of sMPC, the Storeman node never holds the user’s private key, but only calculates the transaction in an anonymous and secure state, and the technology prevents the Storeman nodes from colluding.
  2. Even after technical guarantees, we also designed a “double protection” against the risk from an economic point of view, that is, each node participating as a Storeman needs to pledge WAN in the contract as a “stake”. The pledge of WAN will be greater than the amount of any single transaction as a guarantee against loss of funds.
If the node is malicious (even if it is a probability of one in a billion), the community will be compensated for the loss caused by the malicious node by confiscation of the staked WAN. This is like the POS mechanism used by ETH, using staking to prevent bad behavior is a common principle.
Neutrino: On December 12th, the mainnet of Wanchain 3.0 was launched. Wanchain 3.0 opened cross-chain transactions between Bitcoin, Ethereum and ERC20 (such as MakerDao’s stable currency DAI and MKR). What does this version mean for you and the industry? This upgrade of cross-chain with Bitcoin is the biggest bright spot. So, if now you are able to use Wanchain to make transactions between what is the difference between tokens, then what is the difference between a cross chain platform like Wanchain and cryptocurrency exchanges?
Lini: The release of 3.0 is the industry’s first major network which has crossed ETH and BTC, and it has been very stable so far. As mentioned above, many cross-chain, password-protected theoretical designs are very distinctive, but for engineering implementation, the whether or not it can can be achieved is a big question mark. Therefore, this time Wanchain is the first network launched in the world to achieve this. Users are welcome to test and attack. This also means that Wanchain has connected the two most difficult and most challenging public networks. We are confident we will soon be connecting other well-known public chains.
At the same time of the release of 3.0, we also introduced cross chain integration with other ERC20 tokens in the 2.X version, such as MakerDao’s DAI, MKR, LRC, etc., which also means that more tokens of excellent projects on Ethereum will also gradually be integrated with Wanchain.
Some people will be curious, since Wanchain has crossed so many well-known public chains/projects; how is it different with crypto exchanges? In fact, it is very simple, one centralized; one distributed. Back to the white paper of Nakamoto, is not decentralization the original intention of blockchain? So what Wanchain has to do is essentially to solve the bottom layer of the blockchain, one of the core technical difficulties.
Anyone trying to create a DEX (decentralized exchange); digital lending and other application scenarios can base their application on Wanchain. There is a Wanchain based DEX prototype made by our community members Jeremiah and Harry, which quite amazing. Take a look at this video below.
https://www.youtube.com/watch?v=codcqb66G6Q
Neutrino: What are the specific application use cases after the launch of Wanchain 3.0? Most are still exploring small-scale projects. According to your experience, what are the killer blockchain applications of the future? What problems need to be solved during this period? How many years does it take?
Lini:
  1. Wanchain is just a technology platform rather than positioning itself as an application provider; that is, Wanchain will continue to support the community, and the projects which use cross-chain technology to promote a wide range of use cases for Wanchain.
  2. Cross-chain applications that we anticipate include things like: decentralized exchanges, digital lending, cross chain games, social networking dAPPs, gambling, etc. We also expect to see applications using non fungible tokens, for example exchange of real assets, STOs, etc.
  3. We recently proposed the WanDAPP solution. Simply speaking, a game developer for example has been developing on Ethereum, and ERC20 tokens have been issued, but they hope to expand the player base of their games to attract more people. To participate and make full use of their DAPP, you can consider using the WanDAPP solution to deploy the game DAPP on other common platforms, such as EOS, TRON, etc., but you don’t have to issue new tokens on these chains or use the previous ERC20 tokens. In this way the potential user population of the game can be increased greatly without issuing more tokens on a new chain, improving the real value of the original token. This is accomplished completely using the cross-chain mechanism of Wanchain.
  4. For large-scale applications, the infrastructure of the blockchain is not yet complete, there are issues which must first be dealt with such as TPS, sharding, sidechains, state channels, etc. These all must be solved for the large-scale application of blockchain applications. I don’t dare to guess when it will be completed, it depends on the progress of various different technical projects. In short, industry practitioners and enthusiasts need a little faith and patience.
Neutrino community member Block Venture Capital Spring: Will Wanchain be developing any more cross chain products aimed at general users? For example will the wallet be developed to make automatic cross chain transfers with other public chains? Another issue the community is concerned about is the currency issuance. Currently there are more than 100 million WAN circulating, what about the rest, when will it be released?
Lini: As a cross-chain public chain, we are not biased towards professional developers or ordinary developers, and they are all the same. As mentioned above, we provide a platform as infrastructure, and everyone is free to develop applications on us.
For example, if it is a decentralized exchange, it must be for ordinary users to trade on; if it is some kind of financial derivatives product, it is more likely to be used by finance professionals. As for cross-chain wallets which automatically exchange, I’m not sure if you are talking about distributed exchanges, the wallet will not be “automatic” at first, but you can “automatically” redeem other tokens.
Finally, the remaining WAN tokens are strictly in accordance with the plan laid out in the whitepaper. For example, the POS node reward mentioned above will give 10% of the total amount for reward. At the same time, for the community, there are also rewards for the bounty program. The prototype of the DEX that I just saw is a masterpiece of the overseas community developers, and also received tokens from our incentive program.
Neutrino community member’s question: There are many projects in the market to solve cross-chain problems, such as: Cosmos, Polkadot, what are Wanchain’s advantages and innovations relative to these projects?
Lini: As I mentioned earlier, Cosmos and pPolkadot all proposed very good solutions in theory. Compared with Wanchain, I don’t think that we have created anything particularly unique in our theory. The theoretical basis for our work is cryptography, which is derived from the academic foundation of scholars such as Yao Zhizhi and Silvio Micali. Our main strong point is that we have taken theory and put it into practice..
Actually, the reason why people often question whether a blockchain project can be realized or not is because the whitepapers are often too ambitious. Then when they actually start developing there are constant delays and setbacks. So for us, we focus on completing our very solid and realizable engineering goals. As for other projects, we hope to continue to learn from each other in this space.
Neutrino community member Amos from Huobi Research Institute question: How did you come to decide on 21 storeman nodes?
Lini: As for the nodes we won’t make choices based on quantity alone. The S in the POS actually also includes the time the tokens are staked, so that even if a user is staking less tokens, the amount of time they stake them for will also be used to calculate the award, so that is more fair. We designed the ULS (Unique Leader Selection) algorithm in order to reduce the reliance on the assumption of corruption delay (Cardano’s POS theory). which is used for ensuring fairness to ensure that all participants in the system can have a share of the reward, not only few large token holders.
Wu Di, a member of the Neutrino community: Many big exchanges have already begun to deploy decentralized exchanges. For example, Binance, and it seems that the progress is very fast. Will we be working with these influential exchanges in the future? We we have the opportunity to cooperate with them and broaden our own influence?
Lini: I also have seen some other exchange’s DEX. Going back the original point, distributed cross-chain nodes and centralized ones are completely different. I’m guessing that most exchanges use a centralized cross-chain solution, so it may not be the same as the 21 member Storeman group of Wanchain, but I think that most exchanges will likely be using their own token and exchange system. This is my personal understanding. But then, if you are developing cross chain technology, you will cooperate with many exchanges that want to do a DEX. Not only Binance, but also Huobi, Bithumb, Coinbase… And if there is anyone else who would like to cooperate we welcome them!
Neutrino community member AnneJiang from Maker: Dai as the first stable chain of Wanchain will open a direct trading channel between Dai and BTC. In relation to the Dai integration, has any new progress has been made on Wanchain so far?
Lini: DAI’s stable currency has already been integrated on Wanchain. I just saw it yesterday, let me give you a picture. It’s on the current 3.0 browser, https://www.wanscan.org/, you can take a look at it yourself.
This means that users with DAI are now free to trade for BTC, or ETH or some erc20 tokens. There is also a link to the Chainlink, and LRC is Loopring, so basically there are quite a few excellent project tokens. You may use the Wanchain to trade yourself, but since the DEX is not currently open, currently you can only trade with friends you know.
https://preview.redd.it/jme5s99bun621.png?width=800&format=png&auto=webp&s=7ba3d430ba3e7ddcab4dbcdedc05d596d832f5a7

About Neutrino

Neutrino is a distributed, innovative collaborative community of blockchains. At present, we have established physical collaboration spaces in Tokyo, Singapore, Beijing, Shanghai and other places, and have plans to expand into important blockchain innovation cities such as Seoul, Thailand, New York and London. Through global community resources and partnerships, Neutrino organizes a wide range of online an offline events, seminars, etc. around the world to help developers in different regions better communicate and share their experiences and knowledge.

About Wanchain

Wanchain is a blockchain platform that enables decentralized transfer of value between blockchains. The Wanchain infrastructure enables the creation of distributed financial applications for individuals and organizations. Wanchain currently enables cross-chain transactions with Ethereum, and today’s product launch will enable the same functionalities with Bitcoin. Going forward, we will continue to bridge blockchains and bring cross-chain finance functionality to companies in the industry. Wanchain has employees globally with offices in Beijing (China), Austin (USA), and London (UK).
You can find more information about Wanchain on our website. Additionally, you can reach us through Telegram, Discord, Medium, Twitter, and Reddit. You can also sign up for our monthly email newsletter here.
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Wei Dai's B-Money Readthrough Computer Scientist shows you how to use Bitcoin in your screenplay What is HOMOmorphic encryption?? Advanced Cryptography: Promise and Challenges Implementation of Homomorphic Encryption: Paillier - YouTube

You can use homomorphic encryption. Homomorphic encryption is a form of encryption which allows processing of encrypted data and generate an encrypted result which, when decrypted, matches the result of operations performed on the plaintexts. ... A miner receives transactions from other nodes in the Bitcoin network. Every transaction is ... Height Age Transactions Total Sent Total Fees Block Size (in bytes) 651584: 2020-10-07T02:15:40.386Z: 3,012: 1,682.169 BTC: 0.549 BTC: 950,485: 651583: 2020-10-07T02 ... Homomorphic encryption. ... Let’s take a look at an online SHA-256 calculator. SHA-256 is the current gold standard when it comes to cryptographic hashing algorithms. ... 2019 / by Josh Lake How to buy and pay with bitcoin anonymously April 18, 2018 / by Aimee O'Driscoll What bitcoin is and how to buy it and use it April 6, 2018 / by Aimee O ... Currently experimenting on homomorphic encryption using the PALISADE library. I want to apply simple he operations like additions and multiplications on large encrypted inputs. For example input A[... Paillier Homomorphic encryption supports addition and multiplication with plaintext value.. Can I use these properties to calculate the means of cipher-text values? I try to use the following steps: Multiply set of cipher texts (to get there sum in plaintext value)

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Wei Dai's B-Money Readthrough

Why you need threshold signatures to protect your Bitcoin wallet - Duration: 27:34. Arvind Narayanan 826 views. 27:34. Winter School on Cryptography: Fully Homomorphic Encryption - Craig Gentry ... Money as a Democratic Medium The Color of Money: Banking and Racial Inequality (with Slides) - Duration: 1:15:33. Harvard Law School 10,247 views Fully Homomorphic Encryption from the Ground Up ... Asymmetric encryption - Simply explained ... 4:40. Math Behind Bitcoin and Elliptic Curve Cryptography (Explained Simply) - Duration ... https://asecuritysite.com/encryption/pal_ex Pitch of the Team "Homomorphic Blockchain: Quantum computing safe and GDPR conform encryption for DLT / Blockchain.” at Blockchained Mobility Hackathon 2018 From July 20th to 22nd 2018 the ...

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