Introduction
Today I will be talking about how privacy is being addressed by various blockchain solutions. I provided a brief introduction on why privacy is needed on blockchain and some solutions trying to address it in my previous post, https://www.securityprivacyrisk.com/what-are-privacy-coins/
Anonymity, Privacy, & Fungibility
When Bitcoin was introduced, it was said that transactions were anonymous. It was later discovered that the transactions were indeed pseudonymous, such that public addresses were alphanumeric numbers and did not have a persons name assigned to it, the moment a person is linked to a public address, the transaction is no longer anonymous.
Some people are okay sharing their personal information on social media, while others not so much. Obviously, the number of people who a concerned about their privacy is a very small number compared to extroverts.
Other use cases where privacy and anonymity are paramount is the use of blockchain for storing personal information such as health records, identity, and personal information such as date of birth, social security numbers, and other personal information.
To address this requirement for privacy, anonymity, and fungibility, various off-chain and on-chain solutions are being proposed.
Possible solutions
Some solutions that are available to address privacy, anonymity, and fungibility are accomplished via mixing:
- Centralized: There are online services such as http://bitmixer.io, where, you send your bitcoin to a site, they charge you a fee for this service, and they return your bitcoin to your specified address. The issue with these sites is the trust, what if the site runs away with your bitcoin
- De-centralized: There are privacy tokens that are implemented mixing using the protocol such as:
- Ring Signatures: Another method to anonymize your transactions. It uses cryptography were encryption keys are added to the ring and when a transaction is signed a session key is generated from the key in the ring. Nobody knows which key was used. The more signatures in a ring the better anonymity of the transaction. The previous version of ring signatures only supported anonymizing sender and receiver, not the amount. RingCT was recently introduced that also anonymize the transaction amount.
- CoinJoin: A method where several people agree to add their transactions in a pool and payouts are done from the pool disconnecting sender and receiver.
- Zero-Knowledge Proofs are implementations where for one party (the prover) to prove to another (the verifier) that a statement is true, without sharing the exact information and asserting that the statement is true. Some of the implementations are:
- zkSNARKS – Zero-Knowledge Succinct Non-Interactive Argument of Knowledge
- zkSTARKS – Zero-Knowledge Succinct Transparent Argument of Knowledge
The blockchain is not a solution for every use case. There has to be a genuine need to use blockchain. This particular problem of privacy & anonymity is only an issue in public blockchains, private blockchains are permissioned and implement various controls to address the privacy & anonymity requirements.
Some Privacy Tokens
To address these very issues, privacy coins or privacy tokens have come into existence.
All these tokens are different implementations of the same requirement, making crypto token transactions untraceable for both the receiver and the sender.
Following is a list of tokens that I could find so far, there are many more.
Name |
Symbol |
TPS |
Forked From |
Former Name |
Total Supply |
Founded |
Consensus Algorithm |
Privacy Algorithm |
Protocol |
Transport |
Send Options |
ByteCoin |
BCN |
|
N/A |
|
184.46billion |
1-Jul-2012 |
CryptoNight-PoW |
Ring Signatures |
CryptoNote |
|
|
Monero |
XMR |
1000 |
ByteCoin |
|
Unlimited |
18-Apr-2014 |
CryptoNight-PoW |
RingCT |
CryptoNote |
|
|
CloakCoin |
CLOAK |
|
|
|
4.5million |
3Jun2014 |
X13 |
CloakShield & ENIGMA Transactions |
|
|
|
Aeon Coin |
AEON |
|
Monero |
|
18.4million |
6-Jun-2014 |
CryptoNightLite-PoW |
Ring Signatures |
|
|
|
Verge |
XVG |
100 |
Dogecoin |
DogeCoinDark |
16.5billion |
1-Oct-2014 |
Scrypt, x17, groestl, blake2s & lyra2rev2 |
Wriath |
|
|
|
DASH |
DASH |
56 |
Litecoin |
Darkcoin, XCoin |
18million |
18-Jan-2015 |
|
Coin Join |
|
|
Instant, Private |
PIVX |
PIVX |
50 |
DASH |
|
Unlimited |
1-Feb-2016 |
POS v3 |
zPIV |
|
Public |
SwiftX |
Zcoin |
XZC |
|
N/A |
|
21million |
28-Sep-2016 |
PoW |
zk-SNARKs |
Zerocoin |
|
|
Zcash |
ZEC |
|
Bitcoin |
|
21million |
28-Oct-2016 |
Equihash-POW |
zk-SNARKs |
Zerocash |
|
Transparent Address, Shielded Address |
Zclassic |
ZCL |
|
Zcash |
|
21million |
5-Nov-2016 |
Equihash-POW |
zk-SNARKs |
Zerocash |
|
|
Zoin |
ZOI |
|
Zcoin |
|
21million |
5-Nov-2016 |
Lyra2Zoin-PoW |
zk-SNARKs |
Zerocoin |
|
|
Sumokoin |
SUMO |
|
Monero |
|
88million |
1-May-2017 |
CryptoNight-PoW |
Ring Signatures |
RingCT |
|
|
ZenCash |
ZEN |
|
Zclassic |
|
21million |
23-May-2017 |
Equihash-POW |
zk-SNARKs |
Zerocash |
|
|
Deep Onion |
ONION |
62.5 |
N/A |
|
19.4million |
1-Jul-2017 |
POS+POW |
zk-SNARKs, Coin Join, Ring Signatures |
|
|
DeepSend |
Spectrecoin |
XSPEC |
|
|
|
|
19-Aug-2017 |
POS v3 |
Tor+Ring Signature |
OBFS4 |
Tor |
|
Bitcoin Private |
BTCP |
|
Bitcoin & Zclassic |
|
|
2-Mar-2018 |
Equihash-POW |
zk-SNARKs |
|
|
|
ShadowCash |
SDC |
|
|
|
|
|
|
|
|
|