Comb to Pipeline: Fast Software Encryption Revisited

Abstract. AES-NI, or Advanced Encryption Standard New Instructions, is an extension of the x86 architecture proposed by Intel in 2008. With a pipelined implementation utilizing AES-NI, parallelizable modes such as AES-CTR become extremely efficient. However, out of the four non-trivial NIST-recommended encryption modes, three are inherently sequential: CBC, CFB, and OFB. This inhibits the advantage of using AES-NI significantly. Similar observations apply to CMAC, CCM and a great deal of other modes. We address this issue by proposing the comb scheduler – a fast scheduling algorithm based on an efficient look-ahead strategy, featuring a low overhead – with which sequential modes profit from the AES-NI pipeline in real-world settings by filling it with multiple, independent messages. As our main target platform we apply the comb scheduler to implementations on Haswell, a recent Intel microarchitecture, for a wide range of modes. We observe a drastic speed-up of factor 5 for NIST�...

• Type: Journal
• Year: 2016
• Where: IACR
• Authors: Andrey Bogdanov, Martin M. Lauridsen, Elmar Tischhauser
• Keywords: Biometrics, IACR 2016