compatibility PGP and gnupg

[Vitus Jensen]

Hej!

I get messages from a friend which uses "PGP Desktop 9.9.0 (Build 397)" to
encrypt them which I can't decode using "gpg (GnuPG) 2.0.11":

gpg: checksum error; 6732e7 - 01913c
gpg: [don't know]: invalid packet (ctb=55)

He can read my encrypted replies. I found an old windows machine and
installed PGP Desktop and can decode his messages there so it's not a
transmission problem. Are there incompatibilities between PGP and GnuPG?
Who is to blame?

Vitus

[Casey]

Post by Vitus Jensen
Hej!
I get messages from a friend which uses "PGP

Desktop 9.9.0

(Build 397)" to

Post by Vitus Jensen
encrypt them which I can't decode using "gpg (GnuPG)
gpg: checksum error; 6732e7 - 01913c
gpg: [don't know]: invalid packet (ctb=55)
He can read my encrypted replies. I found an old

windows
machine and

Post by Vitus Jensen
installed PGP Desktop and can decode his messages

there so
it's not a

Post by Vitus Jensen
transmission problem. Are there incompatibilities

betwee PGP and GnuPG?

Post by Vitus Jensen
Who is to blame?
Vitus

It appears that PGP 9.9.0 and GnuPG 2.0.11 are not
completely compatible with each other.
My PGP658ckt09 and GnuPG 1.49 are compatible in both
directions.
Casey

[John Wunderlich]

Post by Vitus Jensen
Hej!
I get messages from a friend which uses "PGP Desktop 9.9.0 (Build
397)" to encrypt them which I can't decode using "gpg (GnuPG)
gpg: checksum error; 6732e7 - 01913c
gpg: [don't know]: invalid packet (ctb=55)
He can read my encrypted replies. I found an old windows machine
and installed PGP Desktop and can decode his messages there so
it's not a transmission problem. Are there incompatibilities
between PGP and GnuPG? Who is to blame?
Vitus

For the most part, they are compatible. I did find a discrepancy in
the way PGP generates digital signatures a while back that I believe
mimics your symptoms and might apply to encryption as well. I traced
it down to the way that PGP vs GPG handles non 7-bit ASCII characters
in text files. GPG would simply do a byte-by-byte encoding while PGP
would convert to UTF-8 before encoding. For some reason, GPG has a
problem processing the way that PGP does this conversion. As long as
you stick to 7-bit ASCII, both are the same but if you insert a
special character, things break.

Try having your friend encrypt a binary file (such as a .jpg) and
attach it to an email and see if it will decrypt with GPG. I bet it
will.

Then have your friend send a short 7-bit ASCII only message such as:
The quick brown fox
and see if you can decode it. Avoid any punctuation except commas
and periods. Specifically avoid accented vowels as well as quotes,
apostrophe, and dash characters as some Microsoft applications will
convert them to "smart quotes" or em-dashes which are not 7-bit ASCII
characters.

If that decodes OK, then try inserting a non 7-bit ASCII character
and see if it fails.

How is he PGP encoding his message? Current Window? Clipboard? Plug-
in?

HTH,
John