Re: Re: CRC

From: Bruce Guenter <bruceg(at)em(dot)ca>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Re: CRC
Date: 2000-12-08 20:54:30
Message-ID: 20001208145430.A11989@em.ca
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On Fri, Dec 08, 2000 at 11:10:19AM -0800, Nathan Myers wrote:
> This is very interesting. MD4 is faster than MD5. (MD5, described as
> "MD4 with suspenders on", does some extra stuff to protect against more-
> obscure attacks, of no interest to us.) Which 64-bit CRC code did you
> use, Mark Mitchell's?

Yes.

> Are you really saying MD5 was faster than CRC-32?

Yes. I expect it's because the operations used in MD5 are easily
parallelized, and operate on blocks of 64-bytes at a time, while the CRC
is mostly non-parallelizable, uses a table lookup, and operates on
single bytes.
--
Bruce Guenter <bruceg(at)em(dot)ca> http://em.ca/~bruceg/

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