Breaking One-Round Key-Agreement Protocols in the Random Oracle Model

In this work we deal with one-round key-agreement protocols, called Merkle's Puzzles, in the random oracle model, where the players Alice and Bob are allowed to query a random permutation oracle n times. We prove that Eve can always break the protocol by querying the oracle O(n2 ) times. The long-time unproven optimality of the quadratic bound in the fully general, multi-round scenario has been proven recently by Barak and MahmoodyGhidary. The results in this paper have been found independently of their work.

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Miroslava Sotáková
• Keywords: CORR 2008, Education, One-round Key-agreement Protocols, Random Oracle Model, Random Permutation Oracle