Different passphrase for subkey

[Hauke Laging]

Am Di 30.07.2013, 22:58:37 schrieb atair:
> Hi,
> 
> is it possible to have a master key and several subkeys with the
> subkeys having a different (e.g. shorter) passphrase than the master
> key?

What you are probably looking for is an offline mainkey (see --export-secret-
subkeys). But the answer is: yes. gpg-agent does not care about the connection 
of keys. It asks you even for the same passphrase several times (for different 
components of the same key).

But GnuPG does not support this directly.

1) Export the secret key (--export-secret-keys without --armor)

2) change the passphrase

3) Export again (to a different file, of course)

4) Use gpgsplit on both files (in different directories). The result looks 
like this:

000001-005.secret_key
000002-013.user_id
000003-002.sig
000004-007.secret_subkey
000005-002.sig

5) Now you mix the components of the two groups:
mkdir combined
mv a/000001* a/000002* a/000003* combined/
mv b/000004* b/000005* combined/
cd combined/
cat * > different_passphrases.gpg

6) Delete the key from secring: --delete-secret-key

7) Import the new one: gpg --import different_passphrases.gpg


Hauke
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Crypto für alle: http://www.openpgp-schulungen.de/fuer/bekannte/
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