Re: [TLS] issues with DTLS + PSK
Martin Thomson <martin.thomson@gmail.com> Mon, 05 January 2015 18:41 UTC
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Date: Mon, 05 Jan 2015 10:41:17 -0800
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From: Martin Thomson <martin.thomson@gmail.com>
To: Hannes Tschofenig <hannes.tschofenig@gmx.net>
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Cc: IETF TLS <tls@ietf.org>
Subject: Re: [TLS] issues with DTLS + PSK
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On 5 January 2015 at 10:26, Hannes Tschofenig <hannes.tschofenig@gmx.net> wrote: > Using DTLS-PSK in combination with DH is IMHO not particularly useful > since then you can also switch to a raw public key right away since you > loose all the performance and code size benefits that the PSK mechanism > provides with DTLS. The theory that I've heard regarding this was that we might have two modes: 1. A PSK that mapped directly into session resumption (i.e., you are "resuming" some non-existent session). 2. A PSK that followed the full handshake with DH. While the latter is certainly slow and expensive, I think it was Carsten who suggested that some IoT devices would be interested in - occasionally - doing an ephemeral handshake. Forward secrecy was a desirable property, and some devices would be able to do the work as long it was infrequent and there were no time-critical functions in progress.
- [TLS] issues with DTLS + PSK Nikos Mavrogiannopoulos
- Re: [TLS] issues with DTLS + PSK Martin Thomson
- Re: [TLS] issues with DTLS + PSK Hannes Tschofenig
- Re: [TLS] issues with DTLS + PSK Martin Thomson
- Re: [TLS] issues with DTLS + PSK Hannes Tschofenig
- Re: [TLS] issues with DTLS + PSK Martin Thomson
- Re: [TLS] issues with DTLS + PSK Nikos Mavrogiannopoulos