[cryptography] 5x speedup for AES using SSE5?

Hovav Shacham hovav at cs.stanford.edu
Mon Aug 25 16:02:13 EDT 2008


On Aug 24, 2008, at 5:20 AM, Peter Gutmann wrote:

> Speaking of CPU-specific optimisations, I've seen a few algorithm  
> proposals
> from the last few years that assume that an algorithm can be scaled  
> linearly
> in the number of CPU cores, treating a multicore CPU as some kind  
> of SIMD
> engine with all cores operating in lock-step, or at least engaging  
> in some
> kind of rendezvous every couple of cycles (for example the recently- 
> discussed
> MD6 uses a round of 16 steps, if I read the description correctly)

My impressions from Ron's talk were different.  For multicore  
systems, the tree structure of the hash allows parallelism at a much  
higher granularity.  For hardware implementation, the feedback- 
register structure of the round function means that 16 steps can be  
computed in parallel.  I didn't get the sense that Ron intends for  
the second kind of parallelism to be used in software implementations.

Hovav.

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