AES-NI, symmetric key generation

[Maricel Gregoraschko]

> AES is an algorithm that produces deterministic results. Not really something 
to backdoor like a RNG. 
I admit I haven't looked at the AES-NI instruction set, but I've read that it could be easy for the CPU to reconstruct the key from a sequence of calls typical to AES encryption/decryption (I think implementations even use Intel-provided code), and store it for later retrieval through a secret CPU instruction set.      From: Andre Heinecke <aheinecke at intevation.de>
 To: gnupg-users at gnupg.org; Maricel Gregoraschko <maricelgregoraschko at yahoo.com> 
 Sent: Tuesday, March 10, 2015 5:05 AM
 Subject: Re: AES-NI, symmetric key generation
   
Hi,

To answer your first question regarding gpg4win:

On Monday, March 09, 2015 05:15:14 PM Maricel Gregoraschko wrote:
> Hello All,I would first like to thank you for your effort and time
> developing gnupgp.I have a couple of questions: 1. Does GnuGP (in
> particular, the Windows binaries distributed for gpg4win) use AES-NI, the
> Intel dedicated AES instruction set?

No, it has been disabled due to a bug. I've opened gnupg/issue1919 to track 
this.

> There are some concerns, I'm not sure
> how realistic, about backdoors built into the CPU themselves. 

AES is an algorithm that produces deterministic results. Not really something 
to backdoor like a RNG. 

> I noticed
> there is an option to "configure", --disable-aesni-support. Where can I get
> the full configure command as it was used to build the posted gpg4win
> binaries, to check if that switch was present or not?

http://git.gnupg.org/cgi-bin/gitweb.cgi?p=gpg4win.git;a=blob;f=src/Makefile.am

Look for gpg4win_pkg_<package>_configure (e.g. gpg4win_pkg_libgcrypt_configure)



> Also is there any
> option to turn hardware acceleration on or off at runtime? 

No.

Regards,
Andre

-- 
Andre Heinecke |  ++49-541-335083-262  |  http://www.intevation.de/
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