A 2-round Identification Scheme Secure against Concurrent Man-in-the-Middle Attacks

摘要

We give a discrete logarithm based identification scheme characterized by its high efficiency and strong security. In fact, keeping efficiency as an interactive proof, it needs only 2-round interaction. Moreover, based on tight reduction to the Gap Computational Diffie-Hellman Assumption, and without the random oracle, it is secure against concurrent man-in-the-middle attacks. Our scheme has a prototype scheme similar to half the operation of Diffie-Hellman Key-Exchange. The prototype is secure only against two-phase concurrent attacks based on stronger assumptions. Applying tag technique and employing a one-time signature in the prototype, we get the preferable scheme above.