Re: [TLS] new error alerts?

Dave Garrett <> Fri, 24 July 2015 05:09 UTC

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From: Dave Garrett <>
To: Andrei Popov <>, Eric Rescorla <>
Date: Fri, 24 Jul 2015 01:09:25 -0400
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Subject: Re: [TLS] new error alerts?
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On Thursday, July 23, 2015 10:52:59 pm Andrei Popov wrote:
> Rather than renaming and otherwise modifying the meaning of the existing alerts, would it be better to define new, more granular alerts in 1.3? We can’t ascribe new meanings to alerts generated by the code we’ve shipped in the past.

I'm not proposing changing the meaning of existing alerts. At most, the Negotiated FF-DH draft would need to be updated/fixed.

I'm proposing renaming "insufficient_security" to "unsupported_cipher_suites", which is explicitly what it's been for since TLS 1.0. There isn't a specific error defined for lack of a supported group yet. RFC 4492 just says "fatal handshake failure alert". The Negotiated FF-DH draft has "insufficient_security" for unsupported group. _That_ does change the meaning, as previously it was explicitly defined for cipher issues only. What I want is to add a new "unsupported_groups" alert to use instead. (both here and there) The "client_authentication_failure" alert suggestion is to pull that out of the "handshake_failure" catchall.

I just want to clarify the existing alert, not reuse it for a related but distinctly different alert, and not lump stuff into a catchall that we can't debug. ;)