Ring signature

A ring signature is a digital signature that any one member of a set of users who each hold keys can produce, so that the signed message is endorsed by someone in that set without revealing who. Its central security property is that it is computationally infeasible to determine which member's key was used. Ring signatures resemble group signatures but differ in two ways: the anonymity of an individual signature cannot be revoked, and any set of users can serve as the signing set with no additional setup. A signer computes the signature from the message, their own private key and the public keys of all ring members, and anyone can check it with those public keys alone. Ron Rivest, Adi Shamir and Yael Tauman Kalai invented ring signatures and introduced them at ASIACRYPT in 2001, and their original paper described using them to leak a secret anonymously and to make deniable signatures.