gpg-rsa-key decryption with a mobile

Mike Cardwell gnupg at
Fri Dec 20 10:28:28 CET 2013

* on the Thu, Dec 19, 2013 at 07:03:57PM +0100, Werner Koch wrote:

>> Since you are mentioned in this webpage, do you know by any chance
>> whether gpgsm is vulnerable in a similar way?
> gpgsm uses Libgcrypt and Libgcrypt employs RSA blinding for a long time
> now.  Thus it is not vulnerable.  The reason Libgcrypt has RSA blinding
> is that it is used by online protocols like TLS were it is easy to mount
> certain timing attacks in the LAN.  With GnuPG these calls of network
> based attacks are not possible and thus we did not used blinding in
> GnuPG-1.

I have a V2 OpenPGP SmartCard. I'm wondering if this would be vulnerable
to the attack in question? Also, what about the Crypto Stick? Presumably
these generate the same sort of noise during signing/decryption that
the CPU would, but there's nothing GnuPG can do in software to mask it?

Mike Cardwell
OpenPGP Key    35BC AF1D 3AA2 1F84 3DC3  B0CF 70A5 F512 0018 461F
XMPP OTR Key   8924 B06A 7917 AAF3 DBB1  BF1B 295C 3C78 3EF1 46B4
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