Patent ID: 8675866

Claim:
A method of performing on a message a cryptographic process which includes a plurality of rounds, each round having an associated round key, each round including a plurality of cipher operations comprising: receiving the message at a port; storing the message in a first computer readable storage medium coupled to the port; storing the round keys for a last one of the rounds and a previous round as a mask value times the round key of the previous round, a product of the last and previous round keys, and an inverse of the previous round key; and at a processor coupled to the first computer readable storage medium, applying the plurality of cipher operations for at least one of the rounds sequentially to the message thereby generating a state for each operation, wherein the round includes no S-box cipher operation, includes a cipher round key operation, and at least one inversion operation immediately prior to or following the round key operation, and further includes an affine bijective function respectively following or prior to the round key operation.