Revision of Security Proof on f-OAEP

Abstract

OAEP is widely accepted because of its provable security and practicability. However, there was a twist in the security proof in the random oracle model. Shoup revealed a flaw in the original security proof by Bellare and Rogaway. In this paper, a revision of the security proof is presented to fix the flaw. Furthermore, compared with some existing improved prove methods, the revised proof is applicable for the underlying trapdoor permutation being a general case.