High-speed AES with transformed keys
The Advanced Encryption Standard (AES) cipher can be performed in a manner that preserves the secrecy of cryptographic keys, even under the intense scrutiny of a reverse-engineer observing every aspect of the computation. A method can include loading a key in a non-standard representation. The method can also include processing the key with respect to data in at least three first type rounds and a plurality of second type rounds. The processing the key with respect to data can include either encrypting the data using the key or decrypting the data using the key. The first type rounds can be configured to maintain an order of channels of bits at an output from the order of corresponding channels of bits at an input. The second type rounds can be configured to vary the order of channels of bits at an output from the order of corresponding channels of bits at an input.
1. An apparatus, comprising:
a first first type round unit provided at an input;
a second first type round unit operatively connected to the first first type round unit;
a plurality of second type round units operatively connected to the second first type round unit; and
a third first type round unit operatively connected to at least one of the plurality of second type round units and configured to provide an output based on data provided at the input,
wherein the first first type round unit, the second first type round unit, and the third first type round unit are configured to maintain an order of channels of bits at an output from the order of corresponding channels of bits at an input, and
wherein the plurality of second type round units are configured to vary the order of channels of bits at an output from the order of corresponding channels of bits at an input,
wherein the first first type round unit is configured to receive at least a portion of a key represented in a non-standard representation,
wherein the non-standard representation is selected from alternative representations comprising isomorphic mappings to fields defined by polynomials with coefficients in GF(2) modulo the 30 degree-8 irreducible polynomials.
2. An apparatus, comprising:
a first first type round unit provided at an input;
a second first type round unit operatively connected to the first first type round unit;
a plurality of second type round units operatively connected to the second first type round unit; and
a third first type round unit operatively connected to at least one of the plurality of second type round units and configured to provide an output based on data provided at the input,
wherein the first first type round unit, the second first type round unit, and the third first type round unit are configured to maintain an order of channels of bits at an output from the order of corresponding channels of bits at an input, and
wherein the plurality of second type round units are configured to vary the order of channels of bits at an output from the order of corresponding channels of bits at an input,
wherein the first first type round unit is configured to receive at least a portion of a key represented in a non-standard representation,
wherein the non-standard representation applies an arbitrary polynomial addend with coefficients in GF(2).