4 import subprocess as _subprocess
5 import struct as _struct
8 def _get_stdout(args, stdin=None):
11 stdin_pipe = _subprocess.PIPE
12 p = _subprocess.Popen(args, stdin=stdin_pipe, stdout=_subprocess.PIPE)
13 stdout, stderr = p.communicate(stdin)
16 raise RuntimeError(status)
20 class PGPPacket (dict):
21 # http://tools.ietf.org/search/rfc4880
22 _old_format_packet_length_type = { # type: (bytes, struct type)
23 0: (1, 'B'), # 1-byte unsigned integer
24 1: (2, 'H'), # 2-byte unsigned integer
25 2: (4, 'I'), # 4-byte unsigned integer
31 1: 'public-key encrypted session key packet',
32 2: 'signature packet',
33 3: 'symmetric-key encrypted session key packet',
34 4: 'one-pass signature packet',
35 5: 'secret-key packet',
36 6: 'public-key packet',
37 7: 'secret-subkey packet',
38 8: 'compressed data packet',
39 9: 'symmetrically encrypted data packet',
41 11: 'literal data packet',
44 14: 'public-subkey packet',
45 17: 'user attribute packet',
46 18: 'sym. encrypted and integrity protected data packet',
47 19: 'modification detection code packet',
54 _clean_type_regex = _re.compile('\W+')
56 def _clean_type(self):
57 return self._clean_type_regex.sub('_', self['type'])
59 def from_bytes(self, data):
60 offset = self._parse_header(data=data)
61 packet = data[offset:offset + self['length']]
62 if len(packet) < self['length']:
63 raise ValueError('packet too short ({} < {})'.format(
64 len(packet), self['length']))
65 offset += self['length']
66 method_name = '_parse_{}'.format(self._clean_type())
67 method = getattr(self, method_name, None)
69 raise NotImplementedError(
70 'cannot parse packet type {!r}'.format(self['type']))
74 def _parse_header(self, data):
77 always_one = packet_tag & 1 << 7
79 raise ValueError('most significant packet tag bit not set')
80 self['new-format'] = packet_tag & 1 << 6
81 if self['new-format']:
82 type_code = packet_tag & 0b111111
83 raise NotImplementedError('new-format packet length')
85 type_code = packet_tag >> 2 & 0b1111
86 self['length-type'] = packet_tag & 0b11
87 length_bytes, length_type = self._old_format_packet_length_type[
90 raise NotImplementedError(
91 'old-format packet of indeterminate length')
92 length_format = '>{}'.format(length_type)
93 length_data = data[offset: offset + length_bytes]
94 offset += length_bytes
95 self['length'] = _struct.unpack(length_format, length_data)[0]
96 self['type'] = self._packet_types[type_code]
103 def packets_from_bytes(data):
105 while offset < len(data):
107 offset += packet.from_bytes(data=data[offset:])
111 def migrate(old_key, new_key):
112 """Add the old key and sub-keys to the new key
114 For example, to upgrade your master key, while preserving old
115 signatures you'd made. You will lose signature *on* your old key
116 though, since sub-keys can't be signed (I don't think).
118 old_key_export = _get_stdout(
119 ['gpg', '--export', old_key])
120 old_key_packets = list(
121 packets_from_bytes(data=old_key_export))
122 old_key_secret_export = _get_stdout(
123 ['gpg', '--export-secret-keys', old_key])
124 old_key_secret_packets = list(
125 packets_from_bytes(data=old_key_secret_export))
128 pprint.pprint(old_key_packets)
129 pprint.pprint(old_key_secret_packets)
132 if __name__ == '__main__':
135 old_key, new_key = _sys.argv[1:3]
136 migrate(old_key=old_key, new_key=new_key)