Re: [TLS] raising ceiling vs. floor (was: New Version Notification for draft-moriarty-tls-oldversions-diediedie-00.txt)
Peter Gutmann <pgut001@cs.auckland.ac.nz> Tue, 10 July 2018 16:38 UTC
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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: David Benjamin <davidben@chromium.org>
CC: Hubert Kario <hkario@redhat.com>, Eric Rescorla <ekr@rtfm.com>, "<tls@ietf.org>" <tls@ietf.org>
Thread-Topic: [TLS] raising ceiling vs. floor (was: New Version Notification for draft-moriarty-tls-oldversions-diediedie-00.txt)
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Date: Tue, 10 Jul 2018 16:38:22 +0000
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References: <152934875755.3094.4484881874912460528.idtracker@ietfa.amsl.com> <3161014.mNqxEOqjoE@pintsize.usersys.redhat.com> <CABcZeBP2tZRe96dj6BvCyHZkSyNh+RBt7H2dzO8vsXkQUb+inw@mail.gmail.com> <2926046.DTQ3PP0lUg@pintsize.usersys.redhat.com> <1531237487290.30133@cs.auckland.ac.nz>, <CAF8qwaCAaVzKKccLQKOvgSpPQe+2M8+jDdtJVy5oQM1+56G_2A@mail.gmail.com>
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Subject: Re: [TLS] raising ceiling vs. floor (was: New Version Notification for draft-moriarty-tls-oldversions-diediedie-00.txt)
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David Benjamin <davidben@chromium.org> writes: >EMS does not fix the ServerKeyExchange signature payload. It's still just the >randoms and not the full transcript. Maybe we're talking about different things here, EMS hashes the full transcript, for 1.0 and 1.1 with the dual SHA-1 and MD5 hash, for 1.2 with whatever's negotiated, hopefully SHA-2 (even if SHA-1 is used, you've now got two hashes you need to defeat simultaneously, not one). So while the ServerKeyExchange signature may not detect an attacker able to compromise SHA-1 in real time (and that statement alone should tell you how feasible the attack actually is), the later EMS will. Peter.
- Re: [TLS] Fwd: New Version Notification for draft… Stephen Farrell
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Hubert Kario
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Peter Gutmann
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Eric Rescorla
- Re: [TLS] Fwd: New Version Notification for draft… Peter Gutmann
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Eric Rescorla
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Hubert Kario
- [TLS] raising ceiling vs. floor (was: New Version… Viktor Dukhovni
- Re: [TLS] Fwd: New Version Notification for draft… nalini elkins
- Re: [TLS] Fwd: New Version Notification for draft… Martin Thomson
- Re: [TLS] Fwd: New Version Notification for draft… Martin Rex
- Re: [TLS] Fwd: New Version Notification for draft… Eric Rescorla
- Re: [TLS] Fwd: New Version Notification for draft… Eric Rescorla
- [TLS] Fwd: New Version Notification for draft-mor… Kathleen Moriarty
- Re: [TLS] Fwd: New Version Notification for draft… Loganaden Velvindron
- Re: [TLS] Fwd: New Version Notification for draft… Salz, Rich
- Re: [TLS] Fwd: New Version Notification for draft… Salz, Rich
- Re: [TLS] Fwd: New Version Notification for draft… Alessandro Ghedini
- Re: [TLS] Fwd: New Version Notification for draft… Andrei Popov
- Re: [TLS] Fwd: New Version Notification for draft… Eric Mill
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Peter Gutmann
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Viktor Dukhovni
- Re: [TLS] raising ceiling vs. floor (was: New Ver… David Benjamin
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Peter Gutmann
- Re: [TLS] Fwd: New Version Notification for draft… Viktor Dukhovni
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Hubert Kario
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Phil Pennock
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Hubert Kario
- Re: [TLS] Fwd: New Version Notification for draft… Stephen Farrell
- Re: [TLS] [CAUTION] Re: Fwd: New Version Notifica… Martin Rex
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Peter Gutmann
- Re: [TLS] Fwd: New Version Notification for draft… nalini elkins
- Re: [TLS] Fwd: New Version Notification for draft… Stephen Farrell
- Re: [TLS] raising ceiling vs. floor (was: New Ver… Hubert Kario
- Re: [TLS] Fwd: New Version Notification for draft… Eric Rescorla
- Re: [TLS] Fwd: New Version Notification for draft… Salz, Rich
- Re: [TLS] [CAUTION] Re: Fwd: New Version Notifica… Kathleen Moriarty
- Re: [TLS] Fwd: New Version Notification for draft… Kathleen Moriarty
- Re: [TLS] Fwd: New Version Notification for draft… Kathleen Moriarty
- Re: [TLS] Fwd: New Version Notification for draft… David Benjamin
- Re: [TLS] Fwd: New Version Notification for draft… nalini elkins
- Re: [TLS] Fwd: New Version Notification for draft… Eric Rescorla
- Re: [TLS] Fwd: New Version Notification for draft… Stephen Farrell
- Re: [TLS] Fwd: New Version Notification for draft… Christopher Wood
- Re: [TLS] Fwd: New Version Notification for draft… Yaron Sheffer
- Re: [TLS] Fwd: New Version Notification for draft… Hubert Kario
- Re: [TLS] Fwd: New Version Notification for draft… Jeremy Harris
- Re: [TLS] Fwd: New Version Notification for draft… Artyom Gavrichenkov
- Re: [TLS] Fwd: New Version Notification for draft… Stephen Farrell
- Re: [TLS] Fwd: New Version Notification for draft… Artyom Gavrichenkov