1. A method, implemented at least in part by a computer device, for performing cryptographic processing, said method comprising: performing one of a plurality of cipher operations and a plurality of inverse cipher operations, wherein at least one non-linear transformation operation of said one of a plurality of cipher operations and said plurality of inverse cipher operations is performed utilizing an XMM (Extended Multimedia) register of a central processing unit, and wherein each of said cipher operations and inverse cipher operations comprises a plurality of iterations; and for each iteration of said plurality of iterations with the exception of a final iteration: (a) inserting values indicative of at least a portion of information to be operated on by one of said cipher and inverse cipher operations into said XMM register; (b) performing an exclusive or function (XOR) between said values in said XMM register and an iteration-specific cryptographic key, wherein said iteration specific cryptographic key is accessed using a fixed-timing memory access instruction; (c) non-linearly transforming values in said XMM register; (d) rotating said non-linearly transformed values in said XMM register; and (e) linearly transforming said rotated values in said XMM register, wherein the central processing unit comprises cache memory, and each access time associated with accessing said cache memory is assigned an identical number of clock cycles of said central processing unit.