Mutator Sets and their Application to Scalable Privacy

Abstract

A mutator set is a cryptographic data structure for authenticating operations on a changing set of data elements called items. Informally: - There is a short commitment to the set. - There are succinct membership proofs for elements of the set. - It is possible to update the commitment as well as the membership proofs with minimal effort as new items are added to the set or as existing items are removed from it. - Items cannot be removed before they were added. - It is difficult to link an item\u27s addition to the set to its removal from the set, except when using information available only to the party that generated it. This paper formally defines the notion, motivates its existence with an application to scalable privacy in the context of cryptocurrencies, and proposes an instantiation inspired by Merkle mountain ranges and Bloom filters