Data processing method for chip card, involves replacing random value based on result of comparison between message authentication and control codes, writing value in buffer based on result and executing operation if result is positive

摘要

The method involves initializing memory with a random value and comparing message authentication code with a received control code using a cryptographic algorithm, which uses a secret key. The random value is replaced based on the comparison result and a microprocessor controls writing of the random value in the buffer based on the result. An operation is executed if the authentication code is equal to the received code. Independent claims are also included for the following: (A) data processing device (B) a computer program comprising instructions to implement data processing method, when instructions are executed by a microprocessor.