Subject: PGP 8.1 - One Pass Signature Format

From: "Hasnain Mujtaba" <[email-masked]>
Date: Thu, 14 Jul 2005 13:27:28 -0400

Greetings,

I received a Signed & Encrypted Message from a customer who uses PGP
8.1. The source file was zero bytes long (for reasons unknown). Out of
curiosity, I ran the message through gpg --list-packets and discovered
that the onepass signature message was unusually constructed: onepass
pkt, signature pkt, literal data pkt (output included below).  I then
signed&encrypted a non-zero byte file with PGP. The resulting message
was properly constructed, as expected.

I guess it doesn't matter for zero-byte files what the format ends up
being. But I can't help asking whether I have run into a corner case
bug.

Regards,
Hasnain.

:marker packet:
 50 47 50
:pubkey enc packet: version 3, algo 16, keyid 7D41D4AD53DEA729
        data: [2048 bits]
        data: [2047 bits]
:encrypted data packet:
        length: 146
        mdc_method: 2
gpg: encrypted with 2048-bit ELG-E key, ID 53DEA729, created 2005-07-13
      "testuser <[email-masked]>"
:compressed packet: algo=2
:onepass_sig packet: keyid 353954462BBAC0C9
        version 3, sigclass 00, digest 2, pubkey 17, last=1
:signature packet: algo 17, keyid 353954462BBAC0C9
        version 3, created 1121293327, md5len 5, sigclass 00
        digest algo 2, begin of digest 43 51
        data: [158 bits]
        data: [160 bits]
:literal data packet:
        mode b (62), created 50331648, name="zero3.txt",
        raw data: 0 bytes
:mdc packet: length=20