[ILUG] serious Debian/Ubuntu security hole found

[paul at clubi.ie]

On Sat, 17 May 2008, Timothy Murphy wrote:

> Are you an expert on Zener diodes, or are you taking the word
> of someone who is?

And are you? Also, mathematics is a wide field - are you an expert on 
random numbers and PRNGs? ;)

At the end of the day, engineers have to use their reasoning and 
experience to figure out how to best apply the results from the 
physical, mathematical and computational sciences - and not always 
with ful understanding of the theory that lead to those results. My 
understanding is that best practice at the moment is to try mix* 
empirical entropy together with a cryptographic PRNG**, to try get 
the best of both worlds - so knowledge of both inputs is required to 
know the output**.

Experience tells us that even once popular and widely-used PRNG 
algorithms can later be found to have flaws. Also, we're all 
well-aware that the real world is both malleable and not 
well-understood.

I'm curious why people here should favour your arguments and ignore 
best-practice in computer engineering. If your arguments should be so 
convincing then surely we should we be reading of them in a paper in 
a peer-reviewed journal? :)

--paulj

* This can be done in ways that ensure output always contains
   supposed entropy from both, or done so that empirical entropy is
   mixed in with the PRNG as it's available.

** The OpenSSL one uses SHA-1

*** Course, this is easy to get wrong too, OpenSSL had a big flaw
     ages ago:

     http://www.mail-archive.com/openssl-announce@openssl.org/msg00024.html

regards,
-- 
Paul Jakma	paul at clubi.ie	paul at jakma.org	Key ID: 64A2FF6A
Fortune:
"Imitation is the sincerest form of television."
-- The New Mighty Mouse