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> Wed, 11 July 2018 04:58 UTC
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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Hubert Kario <hkario@redhat.com>
CC: David Benjamin <davidben@chromium.org>, 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: Wed, 11 Jul 2018 04:57:59 +0000
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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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Hubert Kario <hkario@redhat.com> writes: >defeating two hashes, when both use use the Merkle-Damgård construction, is >not much harder than breaking just one of them (increase of work factor less >than 2) "In theory there is no difference between theory and practice. In practice there is". I'm aware of this long-standing theoretical weakness around multicollisions. I'm just as aware that in the fifteen-odd years since the Joux paper, no-one has ever managed to demonstrate an even remotely practical attack on dual hashes, despite the hugely tempting target of all of SSL/TLS being there as a reward. In fact the sole (significant) surviving member of the MD5/SHA-1 era, RIPEMD-160, remains unbroken and uses dual hash chains within the same function, not even as two independent functions. So I'm not losing any sleep over this. >not after quantum computers ... or captured alien technology, or magic, or anything involving pyramids or the Aztecs... >come into play Yeah, not losing any sleep over those either. 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