Re: [Cfrg] draft-irtf-cfrg-curves question
Ilari Liusvaara <ilariliusvaara@welho.com> Mon, 28 December 2015 19:29 UTC
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Date: Mon, 28 Dec 2015 21:29:54 +0200
From: Ilari Liusvaara <ilariliusvaara@welho.com>
To: Jim Schaad <ietf@augustcellars.com>
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Subject: Re: [Cfrg] draft-irtf-cfrg-curves question
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On Mon, Dec 28, 2015 at 11:14:43AM -0800, Jim Schaad wrote: > In the process of going through an implementation and dealing with the > latest set of questions about non reduced public keys, I ended up with a > question that has some implementations > > If the public key I am given has not be reduced, then I compute > > K_B' = K_B mod p > > Now when I run the KDF function, I am supposed to include K, K_A and K_B in > the key derivation step. The question is should I be using K_B or K_B'? Well, as a datapoint, do that in TLS 1.3 or TLS 1.2-EMS and it will hash K_B (as it would in SSH). And with ECDH-ES/ECDH-SS, that's matter of distributing the public keys correctly. -Ilari
- [Cfrg] draft-irtf-cfrg-curves question Jim Schaad
- Re: [Cfrg] draft-irtf-cfrg-curves question Ilari Liusvaara