C2 Password and Its Safety Research

C2 (Cryptomeria Cipher) is a kind of used in digital copyright protection encryption algorithm, it is a kind Feistel structure of block Cipher. This article through to C2 and related technologies are studied, and again to a typical attack aimed at C2 method was described, in order to make readers understand C2 algorithm's background, the implementation details and the possible method of assault. To C2 related password algorithm problems are reviewed in this paper.