[root@JoeSixpack.net: ]

[Sotiris Vassilopoulos]

[Wednesday, 19/01/2000] Werner Koch:
> > After reading the docs and loading the necessary 'idea' module, it is
> > unclear to me whether gnupg can do conventional symmetric encryption,
> > in a way that is pgp-2 compatible.
> > 
> > 
> > Doing the obvious
> >       gpg --verbose --rfc1991 --digest-algo=md5 --compress-algo 1 \
> >               --cipher-algo=idea -c -a -o encrypted.asc plaintext
> > doesn't seem to work, as
> >       pgp encrypted.asc
> > complains with
> >       Error:  Bad pass phrase.
> > 
> > Going the other way works and gnupg (given the right options) has no
> > problem decoding pgp-2 symmetrically encrypted messages.
> > 
> 
> You have forget to use the '--s2k-mode 0' = PGP 2.6.x method
>                            '--s2k-digest-algo MD5'
>                            '--s2k-cipher IDEA'
> -- 
> Two-a-Day at JoeSixpack.net    www.freenet.de/JoeSixPack    keyid BF3DF9B4
> 
> --
> Root at JoeSixpack.net    www.freenet.de/JoeSixPack    keyid 0xBF3DF9B4
> 

Thanks for your reply. Even after adding these options

        echo -n "test" >key
        gpg \
        --verbose --rfc1991 \
        --digest-algo=md5 --compress-algo 1 --cipher-algo=idea \
        -c --armor  -o encrypted.asc \
        --s2k-mode 0 --s2k-digest-algo MD5 --s2k-cipher IDEA \
        --passphrase-fd 4  \
        plaintext 4<key
        pgp -z`cat key` encrypted.asc

pgp cannot decrypt the file.

If it matters the program versions are
        gpg (GnuPG) 1.0.1	(1.0.0 shows same behavior also)
        Pretty Good Privacy(tm) 2.6.3ia

--
Sotiris Vassilopoulos