Ring Signature.

A digital signature produced by any one of n public keys without revealing which signer was used, introduced by Rivest, Shamir, and Tauman in 2001. It belongs to the Cryptography category of cybersecurity.

A digital signature produced by any one of n public keys without revealing which signer was used, introduced by Rivest, Shamir, and Tauman in 2001.

A ring signature, introduced by Rivest, Shamir, and Tauman in 2001, allows a signer to authenticate a message on behalf of an ad-hoc 'ring' of n public keys such that a verifier is convinced one of the ring members signed but cannot tell which. No coordination, setup, or group manager is required: the signer simply picks the ring and computes a signature using their own private key and the others' public keys. Variants include linkable ring signatures (LSAG, MLSAG, CLSAG) that expose a key image preventing double-spends and traceable ring signatures used for whistleblower-style anonymity. Monero is the flagship deployment, currently using CLSAG plus Bulletproofs+ for amount privacy.

Defences for Ring Signature typically combine technical controls and operational practices, as detailed in the full definition above.

Common alternative names include: RSA ring signature, RST signature.