International Association for Cryptologic Research
The authors study homomorphic authenticated encryption, where privacy and authenticity of data are protected simultaneously. They define homomorphic versions of various security notions for privacy and authenticity, and investigate relations between them. In particular, they show that it is possible to give a natural definition of IND-CCA for homomorphic authenticated encryption, unlike the case of homomorphic encryption. Also, they construct a homomorphic authenticated encryption scheme supporting arithmetic circuits modulo smooth integers, which is chosen-ciphertext secure both for privacy and authenticity.