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From Dustin Sallings <dus...@spy.net>
Subject Re: Why MD5 is used for hashes, also about non-deterministic IDs.
Date Tue, 15 Nov 2011 05:19:47 GMT

On Nov 14, 2011, at 8:41 PM, Alex Besogonov wrote:

> Now, it might not sound too threatening, but this attack breaks the
> main invariant of
> CouchDB - database replicas won't ever be eventually consistent!
> 
> Also, I'd like to use stronger hash just on general principles.


	I'd prefer to get rid of this functionality altogether.  It's wrong even in cases where people
aren't being malicious.

	Example:

	I have a document that represents how many things I've got.

	On node A, I increment the number of things.  I go from 5 things to 6 things.

	On node B, I increment the number of things.  I go from 5 things to 6 things.

	Replication catches up, sees the same digest, and now I have six things -- but this is incorrect.
 I have seven things (or at least a conflict).

	This does will happen with any hash, but no UUID.

-- 
dustin sallings




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