Improved DES and other cryptographic processes with leak minimization for smartcards and other cryptosystems

摘要

A method provided for performing a symmetric cryptographic operation using a secret key with resistance to external monitoring attacks. An input message is obtained and initial unpredictable information is generated. The key, the message and the unpredictable information are combined and a result is derived where the result is a predefined function of the input message and the key and the result is independent of the unpredictable information. Thus, a response is produced based on that result.