Scrambled tweak mode of blockciphers for differential power analysis resistant encryption

A system for improving security of a device comprising a tweak mode encryption engine that:

• receives data;
• applies a block cipher operating in a tweak mode in connection with a counter to a segment of the data;
• applies a mixing function to the counter of the block cipher;
• and
• processes remaining segments of the data with the block cipher while applying the mixing function to the counter for each segment of the data;
• wherein the mixing function is selected from the group consisting of a XOR tree mixing function, substitution-permutation mixing function, and double-mix Feistel mixing function.

A method for of claim for improving security of a device comprising the steps of:

• scrambling with a first mixing unit a first initial value for a first segment of data;
• encrypting with a first block cipher the first segment of data to produce a first ciphertext message from a first plaintext message;
• and
• XORing the scrambled first initial value to the input and output of the first block cipher;
• wherein the first mixing unit is selected from the group consisting of a XOR tree mixing unit, substitution-permutation mixing unit, and double-mix Feistel mixing unit.