gnupg and /dev/random

gnupg and /dev/random

[Gergely Budai]

Dear Community!

It appears to me that gnupg has always been using /dev/random on cygwin since it's first release (1.0.7-1). AFAIK cygwin is using
CryptGenRandom() for this device. According to Wikipedia, several "significant weaknesses" had been found recently in the Windows
2000 and XP implementation of that function. According to that same Wikipedia article, Microsoft is planning to fix that bug with
the release of SP3 for XP, but not planning (at least did not tell to do so) to fix it for Windows 2000.

Since the presence of a strong cryptographical random function is the prerequisite of cryptography and some of us are sill going to
use Cygwin on Windows 2000 in the future, my question is the following:
Would not it be better to configure the future gnupg cygwin releases not to use /dev/random, but the builtin and specially for
windows developped randomness entropy gatherer (rndw32.c)?

Looking forward to your kind oppinions,
Gergely Budai

Sources:
http://en.wikipedia.org/wiki/CryptGenRandom

Re: gnupg and /dev/random

[Lapo Luchini]

Gergely Budai wrote:
> Since the presence of a strong cryptographical random function is the prerequisite of cryptography and some of us are sill going to use Cygwin on Windows 2000 in the future, my question is the following: Would not it be better to configure the future gnupg cygwin releases not to use /dev/random, but the builtin and specially for windows developped randomness entropy gatherer (rndw32.c)?
>   

If we want to change that, it would be better to use a better CSPRNG for 
/dev/random itself, instead of a gnupg-specific work-around.

Personally, I'd use Fortuna for that and would actually volunteer to 
provide a patch, if such a change could be welcome.

-- 
Lapo Luchini
lapo@lapo.it (OpenPGP & X.509)
www.lapo.it (Jabber, ICQ, MSN)

RE: gnupg and /dev/random

[Gergely Budai]

> If we want to change that, it would be better to use a better 
> CSPRNG for 
> /dev/random itself, instead of a gnupg-specific work-around.

I agree. /dev/random could be strengthened.
Until then, I am happy that even a gnupg workaround exists. ;)

> Personally, I'd use Fortuna for that and would actually volunteer to 
> provide a patch, if such a change could be welcome.

I am pretty sure that your contribution which would make /dev/random more robust
will be welcomed by the community.
But ask Corinna, I think she wrote the original code for it.

Cheers,
Gergely

Re: gnupg and /dev/random

[Christopher Faylor]

On Sun, Apr 13, 2008 at 03:02:35PM +0200, Gergely Budai wrote:
>> If we want to change that, it would be better to use a better 
>> CSPRNG for 
>> /dev/random itself, instead of a gnupg-specific work-around.
>
>I agree. /dev/random could be strengthened.
>Until then, I am happy that even a gnupg workaround exists. ;)
>
>> Personally, I'd use Fortuna for that and would actually volunteer to 
>> provide a patch, if such a change could be welcome.
>
>I am pretty sure that your contribution which would make /dev/random more robust
>will be welcomed by the community.
>But ask Corinna, I think she wrote the original code for it.

You don't need to ask permission to present a patch although it is often
good to give a heads up just to make sure that you aren't going down a
bad road.

Regardless, this isn't the mailing list for discussion about changes to
the Cygwin DLL.  The right mailing list is cygwin-developers and remember
that any substantial change requires Red Hat paperwork.

cgf