Problems with compatibility between GnuPG 1.2.2 and PGPTools 7.0.3

David Shaw dshaw at
Thu Sep 4 19:36:02 CEST 2003

On Thu, Sep 04, 2003 at 06:06:41PM +0200, Boix Ricart Marc wrote:
> Hello all,
> I'm trying to validate keys compatibility between the GnuPG v1.2.2 for 
> Microsoft Windows and the soft PGPTools ver 7.0.3.
> With public keys I didn't found any problem, but if I try to import secret 
> keys  errors appears...
> First, when:
>         - I import a RSA legacy pair of keys (generated with PGPTools) in 
> GnuPG,
>         - Next I encrypt a message with the public key (of the previous 
> pair) with PGPTools
>         - And finally I try to decrypt the message with GnuPG
> I receive the error GPGME_Cipher_IDEA (I'm using GPGMe to develop). Do you 
> know if it's normal?

Yes.  PGP assumes that if you are encrypting to a legacy RSA key (aka
"v3 RSA"), then it must use IDEA as the cipher.  GnuPG doesn't have
IDEA by default (see, so this
doesn't work.

The answer is not to use legacy RSA keys.  Use regular modern RSA

> And now, my big problem!
>         - I generate a pair of keys (the type isn't important) with GnuPG
>         - I export the secret key from GnuPG and I import it in PGPTools.
>         - Next I encrypt a message with its public key with GnuPG.
>         - And finally I try to decrypt the message with PGPTools
> The PGPTools not recognize the passphrase of the secret key. Actually, 
> PGPTools has correctly imported the secret key, but it doesn't catch the 
> passphrase, because if I try to sign with the same secret key with 
> PGPTools, it say that the secret key hasn't passphrase.
> I don't understand why! ;P

GnuPG uses a more secure way to store secret keys, but PGP 7 can't
handle it (PGP 8 can).  Do this:

gpg --simple-sk-checksum --edit (thekey)
(Change the password.  You can change it back to the same thing if you

Now you have a secret key that PGP 7 can handle.


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