Zero-knowledge arguments and public-key cryptography (Q1898111)

The paper investigates Diffie-Hellman Public-key systems in which additionally a short random string is shared by all users. Such a system is called a Public-Key Public-Randomness Model (PKPR-Model). The authors show how Rabin's Oblivious Transfer Protocol for two parties can be implemented in a PKPR-Model without any interaction and without trusted center or some distributed fault-tolerant computation. This implementation is secure against receivers with unlimited computational power. Furthermore, a non-interactive implementation of Perfect Zero-Knowledge Arguments for all NP-languages in a PKPR-Model is presented. It is proved that PKPR Perfect Zero-Knowledge Arguments are possible under Quadratic Residuosity Assumption.