Re: Randomness of MD5 vs. SHA1
- From: "Scott Fluhrer" <sfluhrer@xxxxxxxxxxxxx>
- Date: Wed, 10 Feb 2010 13:59:01 -0500
"Tom St Denis" <tom@xxxxxxx> wrote in message
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...