Re: Sanity check

On Fri, 21 Jan 2011 19:09:09 +0100, Nathan <nathan@webr3.org> wrote:

> Just a quick sanity check, TLS connections are encrypted (with a random  
> key) or suchlike, before any certificates are passed, yes? (as in, all  
> data, including certificates, are encrypted over the wire, using keys  
> not found in the certificates).

That depends on the server configuration, there is no such restriction in  
the TLS protocol.

A TLS client certificate can be sent in the initial handshake, or in a  
later renegotiation of the connection. In the latter case it is often  
triggered by the requested URL being in a specific group of URLs that  
require authentication.

Please note that if the server requests authentication during  
renegotiation then the server SHOULD be patched against the TLS Renego  
vulnerability (patched by RFC 5746), and it should require clients to be  
patched against that problem, too.

For reference, the client certificate keys are only used to sign a hash of  
the handshake messages, the result becomes part of the final handshake  
hash. They are not used as part of the keyexhange.


-- 
Sincerely,
Yngve N. Pettersen

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Senior Developer                     Email: yngve@opera.com
Opera Software ASA                   http://www.opera.com/
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Received on Saturday, 22 January 2011 16:49:10 UTC