Introduction
Cryptocurrencies are the primary application of blockchain. Transparency and Privacy are two terms that go side by side concerning cryptocurrencies. Users of cryptocurrencies are looking for more and more Privacy with more adaptability of cryptocurrencies. Anyone can open the bitcoin ledger and check the ongoing transactions and find out the users who are transacting and the amounts of the transactions as well. Hence to increase the Privacy of the cryptocurrency network, Ring Signatures have been introduced to cryptocurrencies.
What are Ring Signatures?
Ring signatures are nothing but digital signatures performed by anyone from a group of members but not possible to know who has done the signature. We can add any group of members without any additional setup. The concept was initially developed to leak the information, especially from high ranking individuals. This way, we will not know who leaked the news, but one can ascertain the information is authentic. The concept is developed by Ron Rivest, Adi Shamir, and Yael Tauman and announced at Asiacrypt in 2001.
Since then, there have been certain developments made in the ring signatures called traceable ring signatures to overcome vulnerabilities raised due to malicious or irresponsible people. The modification or further development of this is what is used in crypto note coins developed to overcome the weaknesses of bitcoin. By this development, the ring signatures were effective enough to obscure the sender’s information in the peer to peer transactions.
Now the concept is further developed called Ringed Confidential Transactions (Ring CT’s), which obscures the transaction amount as well instead of obscuring only the sender’s information. Monero Labs formally announced this in 2015. We all know that Privacy is strictly entitled when it comes to the transactions in the Monero platform, and now we know why, i.e., because of the concept of ring signatures.
How Do They Work?
Cryptocurrencies work on the principle of digital signatures. Ring signatures are digital signatures, which are group signatures. Ring signatures require multiple partial digital signatures of different users who may be part of the network already to form a single digital signature, which is used to sign the transaction. Thus, to validate the signature, multiple private keys are required, which wouldn’t be possible to obtain. The name ring came up because of the use of various users’ output to generate a single digital signature.
Let us see an example of a transaction in Monero blockchain and see how the concept of ring signature works.
⭕ A intends to send 50 coins to B in the Monero network basically to B’s Monero crypto wallet and initiates a transaction.
⭕ In general, this transaction would be signed using A’s private/public key combination, but in this case, a unique one time spend key is generated that starts with the output from the sender’s wallet.
⭕ The other signatures are picked up randomly from the users in the ring from the past outputs in the network to create a unique digital signature, which wouldn’t be possible to determine the original signer.
⭕ Even though the public key of the original sender is used, since the signature is created using different users’ previous outputs, it is not possible to determine the sender’s identity.
Ring signatures have started to become vital, especially where Privacy is a matter of concern in cryptocurrency networks. CryptoNote coins are the most well-known coins for Privacy. Monero and Bytecoins are excellent examples which use ring signatures and Ring CT’s.