Method and system for obfuscating a cryptographic function

A first system for protecting an integrity of a second system, the first system comprising:

• a string determiner for determining a data string to be protected, an integrity of the data string being an indication of the integrity of the second system, the second system processing data according to a cryptographic algorithm;
• a parameterizer for computing a network of look-up tables for implementing the cryptographic algorithm including a cryptographic key, using a redundancy in the look-up tables so that the data string is incorporated into two or more of the look-up tables;
• and
• a processor configured to enable the second system to process data according to the network of look-up tables, wherein a change of the data string in the network of look-up tables causes the system to lose its capability to process the data according to the data processing function.

A data processing system comprising

• a memory for storing a data string to be protected, an integrity of the data string being an indication of the integrity of the data processing system;
• a memory for storing a network of look-up tables for implementing the cryptographic algorithm including a cryptographic key, the data string being incorporated into two or more of the look-up tables by using a redundancy in the look-up tables;
• and
• a processing module for processing data according to the network of look-up tables, wherein a change of the data string in the network of look-up tables causes the system to lose its capability to process the data according to the data processing function.