Abstract: The development process of the Advanced Encryption Standard (AES) was launched in 1997 by the US government through NIST. The Decorrelated Fast Cipher (DFC) was the CNRS proposal for the AES, among 14 other candidates in 1998. It was based on the recent decorrelation theory, to obtain certain security proofs covering linear and differential cryptanalysis. DFC received numerous comments. In particular, Coppersmith discovered a weakness in the key schedule. We address this weakness by a slight modification on DFC. This paper presents the specifications and rationales of DFC version 2, and discusses issues raised during the AES process.