ietf-openpgp
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partial packet lengths in PGP 8

2003-04-08 19:13:14


It seems to me that PGP 8 does not support partial packet lengths for
a a symmetrically encrypted data packet.  Is this a known bug, and if
so is there a work-around?  There are some situations where it would
be very useful for me to be able to generate messages from a stream where
I don't know the length ahead of time and have them still decrypt under
PGP 8.

Specifically, the following packet seems to break it:

c9e39697376314f4fbede026e0bae28397cc98e16881e0ece0f2e2095e6bfee12680e056e000e0cc00

Or broken down into lengths:

c9 (tag indicating symmetrically encrypted data packet)
e3 (partial length of 8)
9697376314f4fbed
e0 (partial length of 1)
26
e0 (partial length of 1)
ba
e2 (partial length of 4)
8397cc98
e1 (partial length of 2)
6881
e0 (partial length of 1)
ec
e0 (partial length of 1)
f2
e2 (partial length of 4)
095e6bfe
e1 (partial length of 2)
2680
e0 (partial length of 1)
56
e0 (partial length of 1)
00
e0 (partial length of 1)
cc
00 (final zero length tag)

Here's the actual message that was generated from.  It's just the message
"xx" encrypted with the password "test".  Decrypts fine with gpg.

-----BEGIN PGP MESSAGE-----

jA0EAwMCPAgVwxrjQWlgyeOWlzdjFPT77eAm4Lrig5fMmOFogeDs4PLiCV5r/uEmgOBW
4ADgzAA=
=N9CU
-----END PGP MESSAGE-----

Thanks,
Brian Smith