ENCRYPTION PROCESSING DEVICE, ENCRYPTION PROCESSING METHOD, AND COMPUTER PROGRAM

摘要

A device and method for realizing high-speed computation in hyperelliptic curve encryption is disclosed. In a hyperelliptic curve cryptography of genus g, when a normal factor having a weight equal to the genus g is an object factor of scalar multiplication, it is judged whether or not the normal factor can be divided into theta factors defined as factors having weights smaller than the genus g. If the normal factor can be divided, the normal factor is divided to produce theta factors, and a scalar multiplication execution section is allowed to execute scalar multiplication to which the theta factors are applied. With this constitution, high-speed scalar multiplication having a lessened computational complexity can be executed, thereby realizing high-speed encryption processing operation.