Zero-knowledge protocols for code-based public-key encryption

Code-based public-key encryption schemes (PKE) are the candidates for post-quantum cryptography, since they are believed to resist the attacks using quantum algorithms. The most famous such schemes are the McEliece encryption and the Niederreiter encryption. In this paper, we present the zero-knowledge (ZK) proof systems for proving statements about data encrypted using these schemes. Specifically, we present a proof of plaintext knowledge for both PKEs, and also a verifiable McEliece PKE. The main ingredients of our constructions are the ZK identification schemes by Stern from Crypto93 and by Jain, Krenn, Pietrzak, and Tentes from Asiacrypt12.