When the suffering authentication device and the authentication system, the challenge data is received from

摘要

PROBLEM TO BE SOLVED: To provide a digital authentication system tolerant to a differential power analysis in a challenge response authentication system.;SOLUTION: The device 200 to be authenticated comprises a free run counter 201 for causing the device 200 to generate a variation value, a memory 208 for storing encryption message, an encryption circuit 207, and a sequence section 202 for receiving a random number r from an authentication device 100, acquiring a count generated from the free run counter 201 and an encryption message stored in the encryption message memory 208, creating a deformed encryption message by altering the encryption message on the basis of the count, creating a response encryption message by encrypting the deformed encryption message and the random number r through the encryption circuit 207 and transmitting the response encryption message to the authentication device 100.;COPYRIGHT: (C)2005,JPO&NCIPI