GnuPG and PGP 2.6: unusable public key

[Anonymous]

> On Thursday 18 October 2001 10:02, Tommi Vainikainen wrote:
> I got public key from a friend.  That key was generated with some
> version of PGP 2.6.  To import that key I had to use
> --allow-non-selfsigned-uid, but now the key is in my public
> keyring.

I have put together a short cheat sheet for GnuPG <-> PGP 2.6 interoperation.
It is assumed here that you have compiled and enabled the IDEA module
for GnuPG and that you work on a unix-like OS. Here it is:

###################################################
Add your PGP-2 public key to your public gpg keyring (don't use -a)
	pgp -kx my_user_id rsa-key 
	gpg --import rsa-key.pgp
Add your PGP-2 secret key to your secret gpg keyring (don't use -a)
	pgp -kx my_user_id rsa-key-secret ~/.pgp/secring.pgp
	gpg --import rsa-key-secret.pgp
	rm rsa-key-secret*

Now you can open PGP-2 signed/encrypted/signed+encrypted messages

###################################################
Conventional (symmetric) PGP-2 compatible encryption:
			(must know filesize; won't work with pipes)
	file_to_encrypt=top-secret.txt
	gpg --rfc1991 \
	--verbose --digest-algo=md5 --compress-algo 1 --cipher-algo=idea \
        --set-filesize `find $file_to_encrypt -printf '%s'` $file_to_encrypt

Conventional (symmetric) PGP-2 compatible decryption:
	gpg --verbose --digest-algo=md5 --compress-algo 1 --cipher-algo=idea

###################################################
Encrypting mail with their PGP-2 key:
	gpg --rfc1991 --verbose --digest-algo=md5 --compress-algo 1 \
		--cipher-algo=idea -ae -o new.asc \
		-r their_pgp2_userid messagefile

Signing mail with your PGP-2 key:
	(pgp2 can only check --clearsign singatures and text files only)
	gpg --rfc1991 --verbose --digest-algo=md5 --compress-algo 1 \
		--cipher-algo=idea --default-key=my_pgp2_userid \
		--clearsign -o new.asc messagefile
	(for binary files use the following)
	file_to_encrypt=top-secret.txt
	gpg --detach-sign --default-key $my_pgp2_userid \
		--output top-secret.txt.sig $file_to_encrypt
	gpg --store -z 0 --output top-secret.txt.lit $file_to_encrypt
	cat top-secret.txt.sig top-secret.txt.lit | gpg --no-literal \
		--store --compress-algo 1  -a --output top-secret.txt.asc
	\rm top-secret.txt.sig top-secret.txt.lit

Signing + encrypting mail with your PGP-2 key and their PGP-2 key:
	file_to_encrypt=top-secret.txt
	my_pgp2_userid=16207E55
	their_pgp2_userid=16207E55
	gpg --detach-sign --default-key $my_pgp2_userid \
		--output top-secret.txt.sig $file_to_encrypt
	gpg --store -z 0 --output top-secret.txt.lit $file_to_encrypt
	cat top-secret.txt.sig top-secret.txt.lit | gpg --no-literal \
		--store --compress-algo 1 --output top-secret.txt.z
	gpg	--no-literal --encrypt --rfc1991 --cipher-algo idea \
		--encrypt-to $my_pgp2_userid --recipient $their_pgp2_userid \
		-a --output top-secret.txt.asc top-secret.txt.z
	\rm top-secret.txt.sig top-secret.txt.lit top-secret.txt.z