Re: cyclical redundancy checksum algorithm(s)?

From: Ron Johnson <ron(dot)l(dot)johnson(at)cox(dot)net>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: cyclical redundancy checksum algorithm(s)?
Date: 2006-09-27 21:25:40
Message-ID: 451AEC54.8040501@cox.net
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On 09/27/06 16:02, Karen Hill wrote:
> Gene Wirchenko wrote:
[snip]
>>> Yet what happens if there is a collision of the checksum for a row?
>> Then you get told that no change has occurred when one has. I
>> would call this an error.
>
> That's exactly what I thought when I read that in his book. I was
> thinking back to the sha1 and md5 algorithms, maybe a special crc
> algorithm is safe from this.

I doubt it. The typical CRC is 32 bits, whereas the MD5 hash is 128
bits and SHA1 is 160 bits.

- --
Ron Johnson, Jr.
Jefferson LA USA

Is "common sense" really valid?
For example, it is "common sense" to white-power racists that
whites are superior to blacks, and that those with brown skins
are mud people.
However, that "common sense" is obviously wrong.
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