Fault Round Modification Analysis of the advanced encryption standard.

This paper describes a new physical analysis technique based on changing the number of the AES rounds. It is an extension of the already known Round Reduction Analysis techniques. Round Modification Analysis is a specific algorithm modification attack. However, the cryptanalysis of the obtained erroneous ciphertexts resorts to the differentiation techniques used by Differential Fault Analysis. Faults were induced thanks to a laser in a software AES, either on the round counter itself or on the reference of its total round number, to obtain an increase or a decrease in the number of rounds. We report here successful attacks and their corresponding cryptanalysis.