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Re: [openpgp] Version 5 key and fingerprint proposal

Vincent Breitmoser <look@my.amazin.horse> Thu, 09 March 2017 12:41 UTC

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Date: Thu, 09 Mar 2017 13:41:10 +0100
From: Vincent Breitmoser <look@my.amazin.horse>
To: openpgp@ietf.org
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References: <87varlou5m.fsf@wheatstone.g10code.de> <20170307230605.GA2@hashbang.sh> <87efy8ntcx.fsf@wheatstone.g10code.de>
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Subject: Re: [openpgp] Version 5 key and fingerprint proposal
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> > Also, but I likely missed the relevant WG thread, why truncate the
> > fingerprint to 200 bits? (Not that this is likely an issue.)
> 
> That was a suggestion from the Berlin meeting.

Can you (or someone else) give some more insight on the requirements
that were identified as a basis for this suggestion?

The SHA-3 contest reaffirmed that SHA-2 is doing just fine in terms of
cryptanalysis, so 160 bits truncated SHA-2 would be just fine even if we
consider strong collision resistance a requirement. But we had this
topic before, and from what I remember noone was able to come up with an
attack scenario where a collision would be useful in any way. Still the
idea now is to add another 40 bits on top?

 - V

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