anonymous DH & MITM

[Eric Murray]

On Thu, Oct 02, 2003 at 12:06:40AM +0100, M Taylor wrote:
> 
> Stupid question I'm sure, but does TLS's anonymous DH protect against
> man-in-the-middle attacks?

No, it doesn't.

> If so, how? I cannot figure out how it would,
> and it would seem TLS would be wide open to abuse without MITM protection so
> I cannot imagine it would be acceptable practice without some form of
> security.

The non DH suites are there in the spec for use when
your security model allows.  Not many uses of TLS do.

Last time I checked, which was a while ago now, very few deployed
https servers offered anon DH suites.  Which is appropriate
since MITM breaks the https security model.

Eric


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