Cryptographic device and associated methods

A communication system comprising:

• a key scheduler providing a key data block comprising a plurality of sub-key data blocks;
• and
• a cryptographic device connected to said key scheduler and comprising
• an input stage receiving an input data block that is X bits in length and the key data block, said input stage adding the X bits of the input data block with a first sub-key data block to generate a summed signal that is X bits in length, and then dividing the summed signal into N first signals that are in parallel, where each first signal is n bits in length so that n*N=X;
• an intermediate stage connected to said input stage and comprising
• a plurality of substitution units operating in parallel, each substituting data within a respective first signal, and
• a diffuser connected to said plurality of substitution units for mixing data to generate a diffused signal, said diffuser comprising at least one shift register and at least one lookup table associated therewith, and
• an output stage connected to said intermediate stage for repetitively looping back the diffused signal to said input stage for combination with a next sub-key data block, said output stage providing an output signal for the cryptographic device after the repetitively looping back is complete.

A method for converting an input data block that is X bits in length and a key data block comprising a plurality of sub-key data blocks into an output signal in a cryptographic device, the method comprising:

• adding the X bits of the input data block with a first sub-key data block to generate a summed signal that is X bits in length, and then dividing the summed signal into N first signals that are in parallel, where each first signal is n bits in length so that n*N=X;
• substituting data within each first signal using a respective substitution unit, with the substitution units operating in parallel to one another;
• mixing data to generate a diffused signal using a diffuser connected to the respective substitution units, the diffuser comprising at least one shift register and at least one lookup table associated therewith;
• and
• repetitively looping back the diffused signal for combination with a next sub-key data block before repeating the substituting and mixing.