Re: [TLS] Simplifying signature algorithm negotiation
Ilari Liusvaara <ilariliusvaara@welho.com> Mon, 29 February 2016 18:42 UTC
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Date: Mon, 29 Feb 2016 20:42:32 +0200
From: Ilari Liusvaara <ilariliusvaara@welho.com>
To: David Benjamin <davidben@chromium.org>
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References: <CAF8qwaCpYqs7ELDcRzXveLLjpL+d-CmBczkxPweh6_RVE1aDeA@mail.gmail.com> <201601152007.12464.davemgarrett@gmail.com> <CAF8qwaBPsLz-vuOvXGZgxzMpaKHwtZixu7NXzfFN4V_R6WT8Tg@mail.gmail.com> <CABcZeBNipj4oLU=FrTp3+CqTg5bh5vBnd04DoNt56=8BRjqobw@mail.gmail.com> <CAF8qwaDUbLmvzibuC7aedOR5TP6Fv3rNz6ft_v3bKu=FHatYgg@mail.gmail.com>
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Cc: ekr <notifications@github.com>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] Simplifying signature algorithm negotiation
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On Mon, Feb 29, 2016 at 05:16:44PM +0000, David Benjamin wrote: > On Fri, Jan 15, 2016 at 8:23 PM Eric Rescorla <ekr@rtfm.com> wrote: > > > > I'm not sure. I agree that the CFRG thing seems to be a new development. > > I'll > > try to confirm my previous opinion or develop a new one over the weekend :) > > > > ekr, did you have confirmed or new thoughts on this change? > > >From elsewhere in the thread, I put together a draft PR if you wanted > something to look at in that form. > https://github.com/tlswg/tls13-spec/pull/404 > It incorporated some of the suggestions in the thread (not mentioning the > really legacy values, pairing NIST curves with hashes, etc.), but that's > not the important part. The meat of the proposal is unifying signature > algorithms under one number and a shared interface, which I think is a > valuable simplification. I think that changing the algorithm negotiation would make it both simpler and more reliable. Current TLS signature negotiation is not able to express real-world constraints (matching of curve and hash[1]). Also, I think the ranging should be as follows: - 01xx: Avoid (would be insecure) - 02xx: Avoid (would be insecure) - 03xx: Avoid (who uses this hash?) - 04xx: Schemes that sign SHA-256 hash - 05xx: Schemes that sign SHA-384 hash - 06xx: Schemes that sign SHA-512 hash - xx00: Avoid ("Anonymous" looks like a mistake) - xx01: Avoid (RSA-PKCS1-v1.5 is obsolete) - xx02: Avoid (DSA is obsolete) - xx03: ECDSA with new hashes - Others: Other schemes Which would allocate the new things as follows (from what I understand RSA-PSS works): - 0404: RSA-PSS/SHA256 - 0504: RSA-PSS/SHA384 - 0604: RSA-PSS/SHA512 - 0004: Ed25519 - 0005: Ed448 Valid for TLS 1.2 and up. [1] This isn't about algorithm strength matching, it is about interop. -Ilari
- [TLS] Simplifying signature algorithm negotiation David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Brian Smith
- Re: [TLS] Simplifying signature algorithm negotia… Dave Garrett
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Hanno Böck
- Re: [TLS] Simplifying signature algorithm negotia… Eric Rescorla
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Brian Smith
- Re: [TLS] Simplifying signature algorithm negotia… Ilari Liusvaara
- Re: [TLS] Simplifying signature algorithm negotia… Ilari Liusvaara
- Re: [TLS] Simplifying signature algorithm negotia… Nikos Mavrogiannopoulos
- Re: [TLS] Simplifying signature algorithm negotia… Hubert Kario
- Re: [TLS] Simplifying signature algorithm negotia… Hubert Kario
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Hubert Kario
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Ilari Liusvaara
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Kurt Roeckx
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Ilari Liusvaara
- Re: [TLS] Simplifying signature algorithm negotia… Eric Rescorla
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Eric Rescorla
- Re: [TLS] Simplifying signature algorithm negotia… David Benjamin
- Re: [TLS] Simplifying signature algorithm negotia… Eric Rescorla
- Re: [TLS] Simplifying signature algorithm negotia… Ilari Liusvaara
- Re: [TLS] Simplifying signature algorithm negotia… Eric Rescorla
- Re: [TLS] Simplifying signature algorithm negotia… Joseph Salowey
- Re: [TLS] Simplifying signature algorithm negotia… Eric Rescorla