On Wed, Mar 22, 2006 at 02:31:37PM -0800, Bill Frantz wrote:

> One of my pet peeves: The idea that the "user" is the proper atom of
> protection in an OS.
> My threat model includes different programs run by one (human) user.  If
> a Trojan, running as part of my userID, can learn something about the
> random numbers harvested by my browser/gpg/ssh etc., then it can start
> to attack the keys used by those applications, even if the OS does a
> good job of keeping the memory spaces separate and protected.

Why would a trojan running in your security context bother with attacking
a PRNG? It can just read your files, record your keystrokes, change your
browser proxy settings, ...

If the trojan is a sand-box of some sort, the sand-box is a different
security context, and in that case, perhaps a different RNG view is

Some applications that consume a steady stream of RNG data, maintain
their own random pool, and use the public pool to periodically mix in
some fresh state. These are less vulnerable to snooping/exhaustion of
the public stream.

The Postfix tlsmgr(8) process proxies randomness for the rest of the
system in this fashion...


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