encrypting using a PGP 7.0 pubkey does not work

[Malte Gell]

Hi there,

just imported successfully a PGP 7.0 public key key into gpg 1.0.7, but=20
when trying to encrypt something with that key I only get "unusable=20
key", gpg --edit-key XXXXXX and showpref gives me that:

pub  1024D/xxxxxxxx  erstellt: 1997-07-24 verf=E4llt: never     =20
Vertrauen: -/f
(1)  xxx xxxxxxx <x.xxxxxxx@xxx.xx.xx>
     Cipher: CAST5, IDEA, 3DES
     Hash:
     Compression:
(2). xxx xxxxxxx <xxx@xxxxxxxxxx.xxx>
     Cipher: CAST5, IDEA, 3DES
     Hash:
     Compression:
(3)  xxx xxxxxxx <xxxxxxxx@xxxxxxx.xx.xx>
     Cipher: CAST5, IDEA, 3DES
     Hash:
     Compression:


Well, gpg 1.0.7 comes with cast, 3des and I also have loaded the idea=20
module, just the hash and compression fields are empty, I tried some=20
options like --openpgp --pgp2 or --pgp6 but none of them worked, does=20
that person who uses PGP 7.0 have to create his key in a special way so=20
it works with GnuPG or can I use that key with some options ?

Regards,
Malte