Re: [TLS] PR#875: Additional Derive-Secret Stage
Martin Thomson <martin.thomson@gmail.com> Thu, 09 February 2017 23:46 UTC
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From: Martin Thomson <martin.thomson@gmail.com>
Date: Fri, 10 Feb 2017 10:46:13 +1100
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To: Eric Rescorla <ekr@rtfm.com>
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Subject: Re: [TLS] PR#875: Additional Derive-Secret Stage
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This is a good idea. On 10 February 2017 at 08:15, Eric Rescorla <ekr@rtfm.com> wrote: > - Address a potential issue raised by Trevor Perrin where an attacker > somehow forces the IKM value to match the label value for Derive-Secret, > in which case the output of HKDF-Extract would match the derived secret. > This doesn't seem like it should be possible for any of the DH variants > we are using, and it's not clear that it would lead to any concrete > attack, but in the interest of cleanliness, it seemed good to address. Just to highlight this point: if we need to add a PQ key exchange, there is no guarantee that it will have exactly the same properties as the key exchange methods we have today. I expect that need to arise relatively soon, so that's an extra good reason to make this change.
- [TLS] PR#875: Additional Derive-Secret Stage Eric Rescorla
- Re: [TLS] PR#875: Additional Derive-Secret Stage Martin Thomson
- Re: [TLS] PR#875: Additional Derive-Secret Stage John Schanck
- Re: [TLS] PR#875: Additional Derive-Secret Stage Hugo Krawczyk