Re: [TLS] Asking the browser for a different certificate

Marsh Ray <marsh@extendedsubset.com> Sat, 27 March 2010 16:59 UTC

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Date: Sat, 27 Mar 2010 11:59:23 -0500
From: Marsh Ray <marsh@extendedsubset.com>
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Subject: Re: [TLS] Asking the browser for a different certificate
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On 3/26/2010 8:14 PM, Martin Rex wrote:
>
> Would the browser be able to
> tell the server in a ClientHelloExtension "Don't bother sending
> me a CertificateRequest, because I don't have one", then
> the server could skip the CertificateRequest message if the
> application/configuration allows the handshake to complete without
> client certificate.

That would be a significant information leak.

Consider an attacker passively sniffing public wifi in a coffee shop
near a targeted organization. Now he sees who has his smart card in the
reader and activated.

- Marsh