Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fast-Track" draft posted
Adam Langley <agl@google.com> Tue, 02 February 2010 15:40 UTC
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Date: Tue, 02 Feb 2010 10:41:07 -0500
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From: Adam Langley <agl@google.com>
To: Nikos Mavrogiannopoulos <nmav@gnutls.org>
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Cc: tls@ietf.org
Subject: Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fast-Track" draft posted
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On Tue, Feb 2, 2010 at 10:32 AM, Nikos Mavrogiannopoulos <nmav@gnutls.org> wrote: > What if I modify the server's messages, so you negotiate to a > ciphersuite I can break, or I can derive information from (say the > length of the plaintext data you send- as with rc4). You will not detect > my attack until you receive the server's finished message, wouldn't you? > > I think this mode is walking on the edge. Obviously, if the server can cause the client to use a NULL cipher (or something very weak) then cut through should not be used. For Android, cut through mode will not be used if the cipher key length is less than 128 bits. The length of the application data records are observable on the wire in any case. The only advantage that an attacker could gain here is to choose a cipher that doesn't pad records to get a slighter more accurate length. Given how extremely valuable saving a round trip is, we choose to make this tradeoff. AGL
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Simon Josefsson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Adam Langley
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Nikos Mavrogiannopoulos
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Adam Langley
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Michael D'Errico
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Nikos Mavrogiannopoulos
- Re: [TLS] Android's cut-through mode & "RequestTi… Brian Smith
- [TLS] Stream multiplexing extension RE: SPDY / Ne… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- [TLS] TLS Performance (was Re: draft-ietf-tls-cac… Michael D'Errico
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Adam Langley
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Adam Langley
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Adam Langley
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Kemp, David P.
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- [TLS] Cached-info substitution Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Kemp, David P.
- Re: [TLS] Cached-info substitution Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] Cached-info substitution Adam Langley
- Re: [TLS] Cached-info substitution Brian Smith
- Re: [TLS] Cached-info substitution Adam Langley
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] Cached-info substitution Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Kemp, David P.
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- [TLS] RFC 5077 (was Re: draft-ietf-tls-cached-inf… Michael D'Errico
- Re: [TLS] Cached-info substitution Adam Langley
- Re: [TLS] Cached-info substitution Wan-Teh Chang
- Re: [TLS] Cached-info substitution Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Simon Josefsson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Kemp, David P.
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Marsh Ray
- Re: [TLS] [POSSIBLE SPAM] Re: draft-ietf-tls-cach… Kemp, David P.
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Marsh Ray
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Yoav Nir
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Simon Josefsson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Simon Josefsson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Simon Josefsson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Joseph Salowey (jsalowey)
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Brian Smith
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Martin Rex
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Simon Josefsson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Donald Eastlake
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Joseph Salowey (jsalowey)
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Marsh Ray
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Simon Josefsson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Stefan Santesson
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Adam Langley
- Re: [TLS] draft-ietf-tls-cached-info-02 / New "Fa… Michael D'Errico