gpg-agent: What is a keygrip?

[Hauke Laging]

Hello,

I just had one of these unpleasant moments when you realize that you haven't 
understood something you believed to have understood for quite a while... :-/

gpg-agent identifies keys by their keygrip. But gpg-agent cares about secret 
keys only. So by my naive understanding the application talking to gpg-agent 
cannot know the keygrip of the key material itself. Because gpg-agent does 
hide this key material from the application.

Is the keygrip computed over the passphrase-protected key material (which the 
application knows)? I.e. does the keygrip change if the passphrase changes?

Or does gpg-agent use only pairs of secret and public keys and the keygrip 
refers to the public key?


Another gpg-agent problem:
It seems to me that you can only check for keys which you know. Is it possible 
to get a list of the known keygrips from gpg-agent? I create keys in an 
account with an empty keyring thus getting only one keygrip would be 
unambiguous.


Hauke
-- 
Crypto für alle: http://www.openpgp-schulungen.de/fuer/bekannte/
OpenPGP: 7D82 FB9F D25A 2CE4 5241 6C37 BF4B 8EEF 1A57 1DF5
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