Abstract: Information security has become a research focus as a result of the increasngly wide application of computers and their networks. After introducing the RSA algorithm with which data encryption is processed,the paper presents the steps for modular multiplication and modular exponentiation based on Montgomery algorithm during RSA encryption and digital signature construction, and gives analysis of the characteristics of Montgomery algorithm for hardware implementation. Design results show that this kind of cryptoprocessor is more practical for it has faster encryption rate, and less die area.