Re: [TLS] Encrypt-then-MAC again (was Re: padding bug)
mrex@sap.com (Martin Rex) Thu, 05 December 2013 06:06 UTC
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To: Peter Gutmann <p.gutmann@auckland.ac.nz>
Date: Thu, 05 Dec 2013 07:06:21 +0100
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From: mrex@sap.com
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Subject: Re: [TLS] Encrypt-then-MAC again (was Re: padding bug)
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Peter Gutmann wrote: > Martin Rex <mrex@sap.com> writes: > > >I'm from the "don't-fix-it-if-it-ain't-broken" camp. And the less code needs > >to be changed to adopt some useful feature, the more likely you will see it > >being adopted for patches/maintenance. I have seen *ZERO* compelling reason > >for switching to encrypt-then-mac in TLS. > > Uhh... what? How have you missed ten years of attacks on TLS that take > advantage of MtE? TLS using pad-mac-encrypt is proven secure and that mac-pad-encrypt is a going to provide an attack surface was clearly pointed out by Serge Vaudenay in 2001. This could have been fixed in TLSv1.1 (2006), but was ignored. The attacks that were demonstrated were in the ballpark of what was predicted in 2001. The fragility of GCM worries me personally much more than the attack surface of mac-pad-encrypt, e.g. Cycling Attacks on GCM, GHASH and Other Polynomial MACs and Hashes Markku-Juhani O. Saarinen http://eprint.iacr.org/2011/202.pdf -Martin
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Martin Rex
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Peter Gutmann
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Eric Rescorla
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Watson Ladd
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Juho Vähä-Herttua
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Bodo Moeller
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Nikos Mavrogiannopoulos
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Bodo Moeller
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Martin Rex
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Juho Vähä-Herttua
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Robert Ransom
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Nikos Mavrogiannopoulos
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Watson Ladd
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Juho Vähä-Herttua
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Martin Rex
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Taylor Hornby
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Martin Rex
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Nikos Mavrogiannopoulos
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Watson Ladd
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Martin Rex
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Nikos Mavrogiannopoulos
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Alfredo Pironti
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Paterson, Kenny
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Alfredo Pironti
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Watson Ladd
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Alfredo Pironti
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Martin Rex
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Wan-Teh Chang
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Paterson, Kenny
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Nikos Mavrogiannopoulos
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Paterson, Kenny
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Watson Ladd
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Martin Rex
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Peter Gutmann
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Peter Gutmann
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Peter Gutmann
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Peter Gutmann
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Trevor Perrin
- Re: [TLS] Encrypt-then-MAC again (was Re: padding… Watson Ladd