On the Security of Practical and Complete Homomorphic Encrypted Computation

Abstract

Security with respect to the operator as an adversary is considered for processors supporting unbounded general purpose homomorphic encrypted computation. An efficient machine code architecture is defined for those platforms and it is proved that user programs expressed in it are cryptographically obfuscated, guaranteeing privacy though they, their traces and (encrypted) data are visible to the operator. It is proved that encrypted user data cannot be deciphered by the operator, nor may programs be altered to give an intended result. A compiler is defined and it is proved that any recompilation produces uniformly distributed random variations in runtime data, supporting cryptographic obfuscation