Graphics Processing Units (GPUs) present large potential performance gains within stream processing applications over the standard CPU. These performance gains are best realised when high computational intensity is required across large amounts of mostly independent input elements. The GPU's success in general purpose stream processing has been demonstrated in many diverse fields, though attempts to port cryptographic algorithms to the GPU have thus far met little success. In recent years, GPU architectures have continued to develop a more flexible and uniform programming environment. These developments have overcome a lot of previously encountered restrictions in cipher implementations. We present novel approaches for the implementation of the AES block cipher encryption algorithm on these GPUs. This work also serves as a precursor for future cipher implementations on the most advanced GPU architecture, the recently released Nvidia G80, which now includes integer support and a si...