Extending the functionality of blind accumulators: contexts

Abstract

Blind accumulators collect private keys of eligible entities in a decentralized manner not getting information about the keys. Once the accumulation is complete, an entity processes the resulting accumulator deriving a public key that refers to the private key previously added by this entity. We extend the blind accumulator scheme with the context functionality so that the derived public key is bound to a specific context and it is hard to associate this key with other public keys of the same entity derived in different contexts. Blind accumulators with contexts are useful in various e-voting scenarios, for example in revoting. We provide an implementation of the extended blind accumulator scheme and justify its security