A ring signature is a type of digital signature that enables anonymous endorsement. Any member of a group of users that each have keys can perform a ring signature. One can thus infer, from a ring signed message, that someone in a particular group endorsed the message, even when one does not know which individual in particular. Ring signatures are used in projects such as Monero, where transactions keys are mixed with those from 5-10 unrelated keys ('mixins') from previous transactions, which are themselves obfuscated and not associated with the same wallet address. This architecture grants the true signer of a Monero transaction pluasible deniability in any associated illicit activity.