[plasma] Verifying the signature of the LockBox.

Alan Borland <Alan.Borland@BoldonJames.com> Wed, 13 March 2013 10:21 UTC

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From: Alan Borland <Alan.Borland@BoldonJames.com>
To: "'plasma@ietf.org'" <plasma@ietf.org>
Thread-Topic: Verifying the signature of the LockBox.
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Date: Wed, 13 Mar 2013 10:21:20 +0000
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Subject: [plasma] Verifying the signature of the LockBox.
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[Boldon James classification: UNMARKED EXTERNAL]

When we open a message we have to determine if the message is a traditional S/MIME message or a Plasma message.  This is done by inspecting the CMS envelopedData layer looking for a Plasma LockBox. If the lockbox is found we verify the SignedData signature, but this got me thinking.  Should we verify just the integrity of the signature itself or should we also perform a full certificate path validation as well?   This would mean every user needs to trust a certificate from the Plasma Server (additional overhead - is this an issue?), but then if the Plasma Server is somehow compromised this would be a way of returning the error to the client.

I couldn't decide either way, at the moment we're doing a full certificate path validation.

Alan.

Alan Borland

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