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Re: MAC speeds



>>>>> "Bart" == Bart Preneel <Bart.Preneel@esat.kuleuven.ac.be> writes:

 Bart> Yes it can be made faster.  See
 Bart> http://www.esat.kuleuven.ac.be/~bosselae/fast.html

 Bart> --Bart

 Bart> On Thu, 9 Mar 2000, Bill Manning wrote:

 >> % % Tero Kivinen reports a time of 154000 cycles (308
 >> microseconds) for % HMAC-MD5 on 2048 bytes on a 500MHz Alpha.  % %
 >> That's slower than today's fast ciphers, notably the AES
 >> candidates, % which are below 40 cycles/byte. Some people seem to
 >> be making decisions % on this basis.  % % But there are faster
 >> implementations of MD5. Furthermore, there are % much faster MACs.
 >> ...  % ---Dan
 >> 
 >> I'm not sure that MD5 can be made too much faster.  see:
 >> 
 >> http://www.isi.edu/~touch/pubs/sigcomm95.html

Antoon's numbers are quite impressive.  On the other hand, the number
quoted from Tero is very bad even for C code run through a poor
compiler.  I make it to be about 4800 cycles per hash block.  I get
about 1600 cycles per block on a MIPS processor, which is a single
issue machine, for C code run through gcc.  Neither has Rotate as a
primitive instruction, so they are at a bit of a disadvantage compared 
to the x86, but it seems reasonable that you should be able to get
down to about 1k cycles per block or so.

	paul


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