Re: [TLS] HTTPS client-certificate-authentication in browsers
Peter Gutmann <pgut001@cs.auckland.ac.nz> Thu, 28 July 2011 06:11 UTC
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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: mrex@sap.com
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Date: Thu, 28 Jul 2011 18:11:03 +1200
Cc: tls@ietf.org
Subject: Re: [TLS] HTTPS client-certificate-authentication in browsers
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Martin Rex <mrex@sap.com> writes: >Anders Rundgren wrote: >> Lots of banks wants to use CCA for their users. > >That is a non sequitur. > >Banks (here in Germany) have abandoned tradtional TANs based on the >unconditional presumption that client PCs are infested with malware, and >most banks in Germany are currently replacing indexed TANs (iTAN) presumably >based on the perception that malware on clients (trojans/phishing) has caught >up with iTAN procedure complexity. > >At this point, with the presumption that all client PCs are thoroughly >infested with malware, going for a Single Sign-On mechanism would be >completely braindead and irresponsible. That was my feeling as well. Moving from TANs (or plain passwords if you're a US bank) to client certs is at best pointless and at worst a step backwards in security. Even if you could overcome the monumental usability problems (and there's no evidence that we can do this), you end up with a mechanism that's even less secure than basic TANs because use of a TAN requires human intervention while a MITB (man-in-the-browser) can use your private key to sign whatever they want as often as they want without your knowledge. Client- side PKI was designed for an attack model invented by cryptographers to justify the use of fun crypto stuff, but it has little (if anything) to do with the threats that we're actually facing today. Peter.
- [TLS] HTTPS client-certificate-authentication in … Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Peter Saint-Andre
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Paul Wouters
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Daniel Kahn Gillmor
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] HTTPS client-certificate-authentication… Matt McCutchen
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Stefan Winter
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] HTTPS client-certificate-authentication… Anders Rundgren
- Re: [TLS] HTTPS client-certificate-authentication… Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] EU cards Anders Rundgren
- Re: [TLS] EU cards Henry Story
- Re: [TLS] EU cards Blumenthal, Uri - 0668 - MITLL
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex
- Re: [TLS] EU cards Anders Rundgren
- Re: [TLS] EU cards Peter Gutmann
- Re: [TLS] EU cards Peter Gutmann
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] EU cards Anders Rundgren
- Re: [TLS] EU cards Henry Story
- Re: [TLS] EU cards Nikos Mavrogiannopoulos
- Re: [TLS] EU cards Yoav Nir
- Re: [TLS] EU cards Blumenthal, Uri - 0668 - MITLL
- Re: [TLS] HTTPS client-certificate-authentication… Wan-Teh Chang
- Re: [TLS] EU cards Henry Story
- Re: [TLS] HTTPS client-certificate-authentication… t.petch
- Re: [TLS] HTTPS client-certificate-authentication… Peter Gutmann
- Re: [TLS] HTTPS client-certificate-authentication… Martin Rex