[ILUG] serious Debian/Ubuntu security hole found

[paul at clubi.ie]

On Thu, 15 May 2008, Timothy Murphy wrote:

> My impression is that while random number generation based on 
> quantum theory sounds a nice idea, in practice a mathematical 
> pseudo-random number generator is probably much more reliable, and 
> certainly much simpler.
>
> By definition, it is impossible to test if a source is random; What 
> reason do you have to suppose your "Zener approach" (which I didn't 
> really understand) produces random output?
>
> I haven't seen any evidence that intelligently designed 
> pseudo-random number generators have ever caused any problem. 
> Personally, I'd trust Knuth much more than any DIY device.

Trust a mathematician to put their faith in the abstract over the 
physical ;).

I don't have my Knuth handy to be more specific, but my (terribly 
bad) memory of it is:

- He details some of the tests that exist to detect patterns and help
   detect non-random data.*

- The Knuth work describes PRNG techniques that are seriously old
   (50s or 60s) - I've got this nagging voice in my head that says
   that those PRNGs, that were once state-of-the-art, have long been
   found to have weaknesses, but I dont know for certain.

If we can't determine randonmess, why should trust the output of a 
man-made algorithm that /seems/ random over measurements of physical 
processes that we apparently have good reason to believe /are/ 
random?**

Just evolutionary advances in one field would be enough to render 
those PRNGs flawed, while it would need major, revolutionary advances 
in the other to undermine the empirical, physical-process based RNGs.

???

*  And methinks all PRNGs, such as the openssl one, should constantly
    self-test their output in this way. Perhaps then it wouldn't have
    taken nearly 2 years to detect that Debian was shipping a getpid()
    based PRNG..

** The engineering to measure things seems less hard than the math,
    to me anyway.

regards,
-- 
Paul Jakma	paul at clubi.ie	paul at jakma.org	Key ID: 64A2FF6A
Fortune:
An engineer is someone who does list processing in FORTRAN.