1. An apparatus for performing cryptographic operations, comprising: a cryptographic instruction, received by a computing device as part of an instruction flow executing on said computing device, wherein said cryptographic instruction prescribes one of the cryptographic operations, and wherein said one of the cryptographic operations comprises: a plurality of OFB block cryptographic operations performed on a corresponding plurality of input text blocks; OFB mode logic, operatively coupled to said cryptographic instruction, configured to direct said computing device to update pointer registers and an initialization vector location for each of said plurality of OFB block cryptographic operations; and execution logic, operatively coupled to said OFB block pointer logic, configured to execute said one of the cryptographic operations.