Weakening Security Assumptions and Oblivious Transfer

Claude Crépeau, Joe Kilian

Ivan Damgård, Joe Kilian, Louis Salvail

Claude Crépeau, Joe Kilian

The authors present some general techniques for establishing the cryptographic strength of a wide variety of games. As case studies, they analyze some weakened versions of the standard forms of oblivious transfer. They also consider variants of oblivious transfer that are motivated by coding theory and physics. Among their results, they show that a noisy telephone line is in fact a very sophisticated cryptographic device. They also present an application to quantum cryptography.>

Kai-Yuen Cheong, Takeshi Koshiba

Mueller-Quade, J., Hideki Imai

With oblivious transfer multiparty protocols become possible even in the presence of a faulty majority. But all known protocols can be aborted by just one disruptor. This paper presents more robust solutions for multiparty protocols with oblivious transfer. This additional robustness against disruptors weakens the security of the protocol and the guarantee that the result is correct. We can observe a trade off between robustness against disruption and security and correctness. We give an application to quantum multiparty protocols. These allow the implementation of oblivious transfer and the protocols of this paper relative to temporary assumptions, i.e., the security increases after the termination of the protocol.

Gilles Brassard A, Claude Crépeau, Stefan Wolf