International Association for Cryptologic Research
The researchers introduced the basic concept of privacy homomorphism that allows computation on encrypted data without decryption. It was elegant work that precedes the recent development of fully homomorphic encryption schemes although there were found some security flaws, e.g., ring homomorphic schemes are broken by the known plaintext attacks. In this paper, the authors revisit one of their proposals, in particular the third scheme which is based on the Chinese Remainder Theorem and is ring homomorphic. The previous result is that only a single pair of known plaintext/ciphertext can break this scheme.