Re: including the entire fingerprint of the issuer in an OpenPGP certification

David Shaw <dshaw@jabberwocky.com> Tue, 18 January 2011 22:43 UTC

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Subject: Re: including the entire fingerprint of the issuer in an OpenPGP certification
From: David Shaw <dshaw@jabberwocky.com>
In-Reply-To: <4D3611C1.5050706@fifthhorseman.net>
Date: Tue, 18 Jan 2011 17:43:01 -0500
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On Jan 18, 2011, at 5:18 PM, Daniel Kahn Gillmor wrote:

> On 01/18/2011 05:05 PM, David Shaw wrote:
>> I don't think we want people using other than the consensus fingerprint algorithms and methods.  I suggest we make the first byte a version field, which can be 
>> set to '4' today for the current fingerprint, '5' for v5 keys, etc.
> 
> Are we talking about versioning the fingerprint scheme, or versioning
> the key?  It sounds like a versioned fingerprint scheme, not a versioned
> key scheme to me.
> 
> If we say '4' means the fingerprinting standard in RFC 4880 (OpenPGPv4)
> and '5' means some other fingerprint scheme then we're effectively
> creating a new registry to be managed by IANA, right?

No, this would be another use of the existing public/secret key version registry.  We already have a registry that covers key versions.

>> I suppose we could skip that field and detect version based on size,
>> but why use heuristics when we can know for sure with a version byte?
> 
> We could also be sure if the name of the notation is precise enough.

Sorry - I wasn't clear enough.  Rather than using a notation, I was saying that if that we should define a "true" subpacket (not a notation) for this, but define the subpacket in a flexible enough way that we won't be throwing the subpacket away (or having to maintain it just for V4) when V5 comes.

David