English

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

Computational Complexity 2009-03-24 v3 Cryptography and Security

Abstract

In this paper we study one-round key-agreement protocols analogous to Merkle's puzzles in the random oracle model. The players Alice and Bob are allowed to query a random permutation oracle nn times and upon their queries and communication, they both output the same key with high probability. We prove that Eve can always break such a protocol by querying the oracle O(n2)O(n^2) times. The long-time unproven optimality of the quadratic bound in the fully general, multi-round scenario has been shown recently by Barak and Mahmoody-Ghidary. The results in this paper have been found independently of their work.

Keywords

Cite

@article{arxiv.0801.4714,
  title  = {Breaking One-Round Key-Agreement Protocols in the Random Oracle Model},
  author = {Miroslava Sotakova},
  journal= {arXiv preprint arXiv:0801.4714},
  year   = {2009}
}

Comments

6 pages

R2 v1 2026-06-21T10:07:57.311Z