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 _public_key_algorithms = {
55 1: 'rsa (encrypt or sign)',
56 2: 'rsa encrypt-only',
58 16: 'elgamal (encrypt-only)',
59 17: 'dsa (digital signature algorithm)',
60 18: 'reserved for elliptic curve',
61 19: 'reserved for ecdsa',
62 20: 'reserved (formerly elgamal encrypt or sign)',
63 21: 'reserved for diffie-hellman',
77 _symmetric_key_algorithms = {
78 0: 'plaintext or unencrypted data',
85 7: 'aes with 128-bit key',
86 8: 'aes with 192-bit key',
87 9: 'aes with 256-bit key',
102 _cipher_block_size = { # in bits
103 'aes with 128-bit key': 128,
104 'aes with 192-bit key': 128,
105 'aes with 256-bit key': 128,
109 _compression_algorithms = {
152 _string_to_key_types = {
156 3: 'iterated and salted',
171 0x00: 'binary document',
172 0x01: 'canonical text document',
174 0x10: 'generic user id and public-key packet',
175 0x11: 'persona user id and public-key packet',
176 0x12: 'casual user id and public-key packet',
177 0x13: 'postitive user id and public-key packet',
178 0x18: 'subkey binding',
179 0x19: 'primary key binding',
181 0x20: 'key revocation',
182 0x28: 'subkey revocation',
183 0x30: 'certification revocation',
185 0x50: 'third-party confirmation',
188 _clean_type_regex = _re.compile('\W+')
190 def _clean_type(self):
191 return self._clean_type_regex.sub('_', self['type'])
194 method_name = '_str_{}'.format(self._clean_type())
195 method = getattr(self, method_name, None)
199 return '{}: {}'.format(self['type'], details)
201 def _str_user_id_packet(self):
204 def from_bytes(self, data):
205 offset = self._parse_header(data=data)
206 packet = data[offset:offset + self['length']]
207 if len(packet) < self['length']:
208 raise ValueError('packet too short ({} < {})'.format(
209 len(packet), self['length']))
210 offset += self['length']
211 method_name = '_parse_{}'.format(self._clean_type())
212 method = getattr(self, method_name, None)
214 raise NotImplementedError(
215 'cannot parse packet type {!r}'.format(self['type']))
219 def _parse_header(self, data):
222 always_one = packet_tag & 1 << 7
224 raise ValueError('most significant packet tag bit not set')
225 self['new-format'] = packet_tag & 1 << 6
226 if self['new-format']:
227 type_code = packet_tag & 0b111111
228 raise NotImplementedError('new-format packet length')
230 type_code = packet_tag >> 2 & 0b1111
231 self['length-type'] = packet_tag & 0b11
232 length_bytes, length_type = self._old_format_packet_length_type[
235 raise NotImplementedError(
236 'old-format packet of indeterminate length')
237 length_format = '>{}'.format(length_type)
238 length_data = data[offset: offset + length_bytes]
239 offset += length_bytes
240 self['length'] = _struct.unpack(length_format, length_data)[0]
241 self['type'] = self._packet_types[type_code]
245 def _parse_multiprecision_integer(data):
246 r"""Parse RFC 4880's multiprecision integers
248 >>> PGPPacket._parse_multiprecision_integer(b'\x00\x01\x01')
250 >>> PGPPacket._parse_multiprecision_integer(b'\x00\x09\x01\xff')
253 bits = _struct.unpack('>H', data[:2])[0]
255 length = (bits + 7) // 8
257 for i in range(length):
258 value += data[offset + i] * 1 << (8 * (length - i - 1))
260 return (offset, value)
262 def _parse_string_to_key_specifier(self, data):
263 self['string-to-key-type'] = self._string_to_key_types[data[0]]
265 if self['string-to-key-type'] == 'simple':
266 self['string-to-key-hash-algorithm'] = self._hash_algorithms[
269 elif self['string-to-key-type'] == 'salted':
270 self['string-to-key-hash-algorithm'] = self._hash_algorithms[
273 self['string-to-key-salt'] = data[offset: offset + 8]
275 elif self['string-to-key-type'] == 'iterated and salted':
276 self['string-to-key-hash-algorithm'] = self._hash_algorithms[
279 self['string-to-key-salt'] = data[offset: offset + 8]
281 self['string-to-key-coded-count'] = data[offset]
284 raise NotImplementedError(
285 'string-to-key type {}'.format(self['string-to-key-type']))
288 def _parse_public_key_packet(self, data):
289 self._parse_generic_public_key_packet(data=data)
291 def _parse_public_subkey_packet(self, data):
292 self._parse_generic_public_key_packet(data=data)
294 def _parse_generic_public_key_packet(self, data):
295 self['key-version'] = data[0]
297 if self['key-version'] != 4:
298 raise NotImplementedError(
299 'public (sub)key packet version {}'.format(
300 self['key-version']))
302 self['creation-time'], algorithm = _struct.unpack(
303 '>IB', data[offset: offset + length])
305 self['public-key-algorithm'] = self._public_key_algorithms[algorithm]
306 if self['public-key-algorithm'].startswith('rsa '):
307 o, self['public-modulus'] = self._parse_multiprecision_integer(
310 o, self['public-exponent'] = self._parse_multiprecision_integer(
313 elif self['public-key-algorithm'].startswith('dsa '):
314 o, self['prime'] = self._parse_multiprecision_integer(
317 o, self['group-order'] = self._parse_multiprecision_integer(
320 o, self['group-generator'] = self._parse_multiprecision_integer(
323 o, self['public-key'] = self._parse_multiprecision_integer(
326 elif self['public-key-algorithm'].startswith('elgamal '):
327 o, self['prime'] = self._parse_multiprecision_integer(
330 o, self['group-generator'] = self._parse_multiprecision_integer(
333 o, self['public-key'] = self._parse_multiprecision_integer(
337 raise NotImplementedError(
338 'algorithm-specific key fields for {}'.format(
339 self['public-key-algorithm']))
342 def _parse_secret_key_packet(self, data):
343 self._parse_generic_secret_key_packet(data=data)
345 def _parse_secret_subkey_packet(self, data):
346 self._parse_generic_secret_key_packet(data=data)
348 def _parse_generic_secret_key_packet(self, data):
349 offset = self._parse_generic_public_key_packet(data=data)
350 string_to_key_usage = data[offset]
352 if string_to_key_usage in [255, 254]:
353 self['symmetric-encryption-algorithm'] = (
354 self._symmetric_key_algorithms[data[offset]])
356 offset += self._parse_string_to_key_specifier(data=data[offset:])
358 self['symmetric-encryption-algorithm'] = (
359 self._symmetric_key_algorithms[string_to_key_usage])
360 if string_to_key_usage:
361 block_size_bits = self._cipher_block_size.get(
362 self['symmetric-encryption-algorithm'], None)
363 if block_size_bits % 8:
364 raise NotImplementedError(
365 ('{}-bit block size for {} is not an integer number of bytes'
367 block_size_bits, self['symmetric-encryption-algorithm']))
368 block_size = block_size_bits // 8
370 raise NotImplementedError(
371 'unknown block size for {}'.format(
372 self['symmetric-encryption-algorithm']))
373 self['initial-vector'] = data[offset: offset + block_size]
375 if string_to_key_usage in [0, 255]:
379 self['secret-key'] = data[offset:key_end]
381 self['secret-key-checksum'] = data[key_end:]
383 def _parse_signature_packet(self, data):
384 self['signature-version'] = data[0]
386 if self['signature-version'] != 4:
387 raise NotImplementedError(
388 'signature packet version {}'.format(
389 self['signature-version']))
390 self['signature-type'] = self._signature_types[data[offset]]
392 self['public-key-algorithm'] = self._public_key_algorithms[
395 self['hash-algorithm'] = self._hash_algorithms[data[offset]]
397 hashed_count = _struct.unpack('>H', data[offset: offset + 2])[0]
399 self['hashed-subpackets'] = data[offset: offset + hashed_count]
400 offset += hashed_count
401 unhashed_count = _struct.unpack('>H', data[offset: offset + 2])[0]
403 self['unhashed-subpackets'] = data[offset: offset + unhashed_count]
404 offset += unhashed_count
405 self['signed-hash-word'] = data[offset: offset + 2]
407 self['signature'] = data[offset:]
409 def _parse_user_id_packet(self, data):
410 self['user'] = str(data, 'utf-8')
416 def packets_from_bytes(data):
418 while offset < len(data):
420 offset += packet.from_bytes(data=data[offset:])
424 class PGPKey (object):
425 def __init__(self, fingerprint):
426 self.fingerprint = fingerprint
427 self.public_packets = None
428 self.secret_packets = None
431 lines = ['key: {}'.format(self.fingerprint)]
432 if self.public_packets:
433 lines.append(' public:')
434 for packet in self.public_packets:
435 lines.append(' {}'.format(packet))
436 if self.secret_packets:
437 lines.append(' secret:')
438 for packet in self.secret_packets:
439 lines.append(' {}'.format(packet))
440 return '\n'.join(lines)
442 def import_from_gpg(self):
443 key_export = _get_stdout(
444 ['gpg', '--export', self.fingerprint])
445 self.public_packets = list(
446 packets_from_bytes(data=key_export))
447 if self.public_packets[0]['type'] != 'public-key packet':
449 '{} does not start with a public-key packet'.format(
451 key_secret_export = _get_stdout(
452 ['gpg', '--export-secret-keys', self.fingerprint])
453 self.secret_packets = list(
454 packets_from_bytes(data=key_secret_export))
456 def export_to_gpg(self):
457 raise NotImplemetedError('export to gpg')
460 def migrate(old_key, new_key):
461 """Add the old key and sub-keys to the new key
463 For example, to upgrade your master key, while preserving old
464 signatures you'd made. You will lose signature *on* your old key
465 though, since sub-keys can't be signed (I don't think).
467 old_key = PGPKey(fingerprint=old_key)
468 old_key.import_from_gpg()
469 new_key = PGPKey(fingerprint=new_key)
470 new_key.import_from_gpg()
476 if __name__ == '__main__':
479 old_key, new_key = _sys.argv[1:3]
480 migrate(old_key=old_key, new_key=new_key)