Re: [dispatch] comments on draft-bhjl-x509-srv-00
"John Levine" <johnl@taugh.com> Sat, 23 July 2016 15:53 UTC
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Date: Sat, 23 Jul 2016 15:53:22 -0000
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From: John Levine <johnl@taugh.com>
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Cc: fluffy@iii.ca
Subject: Re: [dispatch] comments on draft-bhjl-x509-srv-00
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>I like the general idea of this and it seems very good timing as we get close to LetsEncrypt >providing free certs for email. My preference would be for this to be general enough that it worked >for other things such and xmpp and sip that use email style addresses. They face the same problem of >how to discover the recipients certificate. The cert lookup in the draft has little to do with e-mail beyond the fact that the lookup keys are (or look like) e-mail addresses. RFC 4387 only provides for S/MIME and PGP cert lookups. If you can use an S/MIME cert for xmpp or sip, perhaps that's all you need. >I’m also a fan of the approach where if the HTTPS server has a cert for the domain example.com ><http://example.com/>, then it can use that cert to sign the actual email certs for >fluffy@example.com <mailto:fluffy@example.com>. This is the semantic pit of despair I mentioned a few messages ago. Some domains are authoritative sources of information for their e-mail users, some aren't, and I don't see any mechanical way to tell the difference. For e-mail, the main use of a cert lookup would be to send encrypted mail to someone who's never written to you. In that scenario, between sending plain text and encrypting to a cert that might be the user's or might be a MITM from his e-mail provider, even the latter doesn't make things worse. R's, John
- Re: [dispatch] comments on draft-bhjl-x509-srv-00 John Levine
- [dispatch] comments on draft-bhjl-x509-srv-00 Cullen Jennings