Re: Randomness of MD5 vs. SHA1




"Tom St Denis" <tom@xxxxxxx> wrote in message
news:fefec602-6438-41cd-9b79-ea364303dcc1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Feb 10, 10:52 am, Milen Rangelov <gat3...@xxxxxxxxx> wrote:
On Jan 26, 5:55 pm, Tom St Denis <t...@xxxxxxx> wrote:

MD5 is computationally cheaper than SHA-1 if that helps.

Well, that's not necessarily true. SHA-1 has 16 more iterations as
compared to MD5, however it lacks multiplication and modulo
operations. Actually, on my box, OpenSSL's implementation of SHA-1 is
a bit faster than MD5 on short (16byte) messages:

Multiplication and modulo operations?

Maybe he got MD5 and RC5 confused...

SHA-1 takes longer because it has more rounds and operates on more
words at a time.

Actually, a full answer would involve an analysis of how the CPU (and cache)
handles both of the operations...

I'd personally write off the 16-byte block size since the calling
overhead is non-trivial at that point.

Why? Doing hashes of small blocks isn't that uncommon...

--
poncho


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