Patent ID: 7711955

Claim:
A cryptographic unit, comprising: key storage configured to store an expanded set of cipher keys for a cipher algorithm, wherein said cipher algorithm is configured to operate on cipher state, wherein the cipher state includes a plurality of rows and a plurality of columns; and a key expansion pipeline comprising a plurality of pipeline stages, wherein during a key expansion mode of operation, each pipeline stage is configured to perform a corresponding step of generating a member of said expanded set of cipher keys according to a key expansion algorithm; wherein during a cipher mode of operation, a portion of said key expansion pipeline is configured to perform a step of said cipher algorithm; wherein to perform said step of said cipher algorithm, said portion of said key expansion pipeline is configured to process said cipher state, wherein a maximum number of columns that said key expansion pipeline is operable to concurrently process is fewer than all of said columns of said cipher state, such that in said cipher mode of operation, said key expansion pipeline is operable to process said cipher state in portions over multiple distinct cycles of operation.