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Re: MDC, gnupg 1.0.3, and PGP7

2000-10-19 08:30:24
On Thu, 19 Oct 2000, Michael Young wrote:

revision of June 15 is dead.  [That revision used tags 18 and 19, and

18 and 19 is right.

I note that gnupg 1.0.3 uses tag 18.  As I started to write this, I noticed
that 1.0.4 was release in source form yesterday -- does it use tag 15 again?

No.

Werner Koch's recent reply suggests that PGP7 also uses tag 15.

I was wrong, it uses 18,19 and I did some interoperability tests.

Would someone be willing to post a sample encryption from PGP7 that uses
an MDC and Twofish?  (I'd also love to see a secret key packet encrypted

Passphrase "test"

-----BEGIN PGP MESSAGE-----
Version: GnuPG v1.0.4a (GNU/Linux)
Comment: For info see http://www.gnupg.org

jA0ECgMCUDpHpGjiZQlg0ooBAHDje+vcyFMyBA5bjCemhEVjPKly7+zNodZM9XwG
Ks9NGi/dpYfKmUbpUzET1wZpIHEt81vDvVhP7VfLbhYvOBXlWxPyr1IV6Pjznkz/
XxYN8O2f276f/fJ45erHG41SS+N/jKrTYgOEJp5cSSzp6NkJ8hLTRYYSUlX21nYZ
sAOiTw1s/j/nX9s=
=Ymv/
-----END PGP MESSAGE-----

Here are the packets:

symkey enc packet: version 4, cipher 10, s2k 3, hash 2
        salt 503a47a468e26509, count 96
:encrypted data packet:
        length: 137
        mdc_method: 2
:literal data packet:
        mode b, created 971969290, name="geheim",
        raw data: 83 bytes
:mdc packet: length=20

And here come the same thing with compression:

-----BEGIN PGP MESSAGE-----
Version: GnuPG v1.0.4a (GNU/Linux)
Comment: For info see http://www.gnupg.org

jA0ECgMC+Mkg2Ij8RYpg0ogBjrSClbfynZowH3o9HDfdSlhBM0IFf8cGqkpcu9Z9
tAF3SciSHV2RRWoObmcUDF5F4gOK81OzB40qbj8DAGHE8BgR13ze/PhswH51H1jY
y6wXLackZ0WA2RYFh6UnbR/i/Gu8/jASOqu1Hmqmy8DK2mGEqfcm/oGGaxJz4e47
7lkaBDBuQfSo
=AJBJ
-----END PGP MESSAGE-----

:symkey enc packet: version 4, cipher 10, s2k 3, hash 2
        salt f8c920d888fc458a, count 96
:encrypted data packet:
        length: 135
        mdc_method: 2
:compressed packet: algo=1
:literal data packet:
        mode b, created 971969488, name="geheim",
        raw data: 83 bytes

The MDC packet is not listed due to a bug/implementation issue.

From packet.h:
        PKT_ENCRYPTED_MDC =18, /* integrity protected encrypted data */
        PKT_MDC           =19, /* manipulaion detection code packet */

Hth,

  Werner


-- 
Werner Koch                             GnuPG key:  621CC013
OpenIT GmbH                             http://www.OpenIT.de

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