inspect PGP packets in PGPy 0.4.x

list_packets.py

#!/usr/bin/env python
# this is a hackish way to inspect the packets in a PGP object with PGPy 0.4.x
# in the future listing packets directly and determining what fields are useful should be part of the API
# this example prints a few packet types in close to the same format as gpg --list-packets
import sys
from pgpy.types import Armorable
from pgpy.packet import Packet
from pgpy.constants import PacketTag


def pgp_packets(text):
    unarmored = Armorable.ascii_unarmor(text)
    data = unarmored['body']
    while data:
        pkt = Packet(data)
        yield pkt


if __name__ == '__main__':
    for fn in sys.argv[1:]:
        with open(fn) as f:
            text = f.read()
    offset = 0
    for packet in pgp_packets(text):
        # if you want to just print the repr for the packet class:
        # print(packet)
        # otherwise, details can be gathered and printed by inspecting packet
        
        # packet header details (these are common to all packet types)
        hdr = {}
        hdr['off'] = offset
        hdr['ctb'] = packet.header.__bytes__()[0],
        hdr['tag'] = packet.header.tag,
        hdr['hlen'] = len(packet.header)
        hdr['plen'] = len(packet) - hdr['hlen']
        hdr['lfmt'] = "new-ctb" if packet.header._lenfmt else ""
        print("# off={off:} ctb={ctb:02x} tag={tag:} hlen={hlen:} plen={plen:} {lfmt:}".format_map(hdr))
        
        # increment offset for the next packet
        offset += hdr['plen'] + hdr['hlen']
        
        # interpreting individual packets depends on each packet, here are a couple to get you started
        # check pgpy/packet/packets.py for the relevant properties in order to add more, or inspect them with dir() or tab completion in ipython
        if packet.header.tag in {PacketTag.PublicKey, PacketTag.PublicSubKey}:
            # private key packets have these fields, plus a few more
            print(":public {} packet:".format("sub key" if packet.header.tag == PacketTag.PublicSubKey else "key"))
            ver = packet.header.version
            algo = packet.pkalg
            created = packet.created
            # "expires" depends on signatures that follow and this example script isn't smart enough for that currently
            print("       version {ver:}, algo {algo:}, created {created:}".format(ver=ver, algo=algo, created=created))
            for i, field in enumerate(packet.keymaterial.__pubfields__):
                print("        pkey[{}]: [{} bits]".format(i, getattr(packet.keymaterial, field).bit_length()))
            print("        keyid: {}".format(packet.fingerprint.keyid))
                  
        if packet.header.tag == PacketTag.UserID:
            # as we work on the packet API this pre-formatting step should become unnecessary
            uid = packet.name
            if packet.comment:
                uid = '{} ({})'.format(uid, uid.comment)
            if packet.email:
                uid = '{} <{}>'.format(uid, uid.email)
                
            print(':user ID packet: "{}"'.format(uid))
        
        if packet.header.tag == PacketTag.UserAttribute:
            print(":attribute packet: [{} image of size {}]".format(packet.image.iencoding.name, len(packet.image.image)))
        
        # TODO: add more packet types here

For a key that is already loaded:

for packet in pgp_packets(str(key)):
    ...