Patent ID: 7225335
Filing Date: 2007-05-29
Classification: G06F

Abstract:
1. An encryption apparatus for performing public-key-cryptosystem encryption processing, comprising: public-key-cryptosystem processing means including a register group composed of registers for retaining values for use in arithmetic operations and registers for capturing the results of the arithmetic operations, said public-key-cryptosystem processing means performing public-key-cryptosystem encryption processing; and hash value generating means for generating a hash value for use in said public-key-cryptosystem processing means, wherein the register group is also used as at least a register group composed of registers for retaining values for arithmetic operations in said hash value generating means and registers for capturing a resultant hash value, and hardware components are changed in a time-sharing manner in accordance with a processing mode, wherein: said public-key-cryptosystem-operation core means includes a bus-changeover switch for changing a bit width, and said hash value generating means includes a bus-changeover switch for changing a bit width which is also used as the bus-changeover switch of said public-key-cryptosystem processing means.