Re: [TLS] New drafts: adding input to the TLS master secret

Marsh Ray <marsh@extendedsubset.com> Tue, 09 February 2010 17:23 UTC

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Date: Tue, 09 Feb 2010 12:24:34 -0500
From: Marsh Ray <marsh@extendedsubset.com>
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To: Eric Rescorla <ekr@networkresonance.com>
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Cc: paul.hoffman@vpnc.org, tls@ietf.org
Subject: Re: [TLS] New drafts: adding input to the TLS master secret
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Eric Rescorla wrote:
> At Mon, 08 Feb 2010 19:27:01 -0800,
> Eric Rescorla wrote:
>> In general, if you have an acceptable amount of entropy you
>> don't need to worry about leaking PRNG output. If you don't
>> you really don't have any business doing TLS.
> 
> This wasn't well phrased.

I liked it.

> If you're a TLS server and you
> just do static RSA, then it is safe to do TLS even without
> a good source of entropy.

It's only safe to that one narrow perspective. Other things:

Did you generate a cert signing request on that box?
The server SSH keys?
Is SSH using DH?
Were stored passwords well-salted?
Is DNS as used by that box vulnerable?
TCP initial sequence numbers broken?
Etc.

- Marsh