3 import hashlib as _hashlib
5 import subprocess as _subprocess
6 import struct as _struct
9 def _get_stdout(args, stdin=None):
12 stdin_pipe = _subprocess.PIPE
13 p = _subprocess.Popen(args, stdin=stdin_pipe, stdout=_subprocess.PIPE)
14 stdout, stderr = p.communicate(stdin)
17 raise RuntimeError(status)
21 class PGPPacket (dict):
22 # http://tools.ietf.org/search/rfc4880
23 _old_format_packet_length_type = { # type: (bytes, struct type)
24 0: (1, 'B'), # 1-byte unsigned integer
25 1: (2, 'H'), # 2-byte unsigned integer
26 2: (4, 'I'), # 4-byte unsigned integer
32 1: 'public-key encrypted session key packet',
33 2: 'signature packet',
34 3: 'symmetric-key encrypted session key packet',
35 4: 'one-pass signature packet',
36 5: 'secret-key packet',
37 6: 'public-key packet',
38 7: 'secret-subkey packet',
39 8: 'compressed data packet',
40 9: 'symmetrically encrypted data packet',
42 11: 'literal data packet',
45 14: 'public-subkey packet',
46 17: 'user attribute packet',
47 18: 'sym. encrypted and integrity protected data packet',
48 19: 'modification detection code packet',
55 _public_key_algorithms = {
56 1: 'rsa (encrypt or sign)',
57 2: 'rsa encrypt-only',
59 16: 'elgamal (encrypt-only)',
60 17: 'dsa (digital signature algorithm)',
61 18: 'reserved for elliptic curve',
62 19: 'reserved for ecdsa',
63 20: 'reserved (formerly elgamal encrypt or sign)',
64 21: 'reserved for diffie-hellman',
78 _symmetric_key_algorithms = {
79 0: 'plaintext or unencrypted data',
86 7: 'aes with 128-bit key',
87 8: 'aes with 192-bit key',
88 9: 'aes with 256-bit key',
103 _cipher_block_size = { # in bits
104 'aes with 128-bit key': 128,
105 'aes with 192-bit key': 128,
106 'aes with 256-bit key': 128,
110 _compression_algorithms = {
153 _string_to_key_types = {
157 3: 'iterated and salted',
172 0x00: 'binary document',
173 0x01: 'canonical text document',
175 0x10: 'generic user id and public-key packet',
176 0x11: 'persona user id and public-key packet',
177 0x12: 'casual user id and public-key packet',
178 0x13: 'postitive user id and public-key packet',
179 0x18: 'subkey binding',
180 0x19: 'primary key binding',
182 0x20: 'key revocation',
183 0x28: 'subkey revocation',
184 0x30: 'certification revocation',
186 0x50: 'third-party confirmation',
189 _signature_subpacket_types = {
192 2: 'signature creation time',
193 3: 'signature expiration time',
194 4: 'exportable certification',
195 5: 'trust signature',
196 6: 'regular expression',
199 9: 'key expiration time',
200 10: 'placeholder for backward compatibility',
201 11: 'preferred symmetric algorithms',
202 12: 'revocation key',
211 21: 'preferred hash algorithms',
212 22: 'preferred compression algorithms',
213 23: 'key server preferences',
214 24: 'preferred key server',
215 25: 'primary user id',
218 28: 'signer user id',
219 29: 'reason for revocation',
221 31: 'signature target',
222 32: 'embedded signature',
236 _clean_type_regex = _re.compile('\W+')
238 def _clean_type(self):
239 return self._clean_type_regex.sub('_', self['type'])
242 method_name = '_str_{}'.format(self._clean_type())
243 method = getattr(self, method_name, None)
247 return '{}: {}'.format(self['type'], details)
249 def _str_public_key_packet(self):
250 return self._str_generic_key_packet()
252 def _str_public_subkey_packet(self):
253 return self._str_generic_key_packet()
255 def _str_secret_key_packet(self):
256 return self._str_generic_key_packet()
258 def _str_secret_subkey_packet(self):
259 return self._str_generic_key_packet()
261 def _str_generic_key_packet(self):
262 return self['fingerprint'][-8:].upper()
264 def _str_signature_packet(self):
265 lines = [self['signature-type']]
266 if self['unhashed-subpackets']:
267 lines.append(' unhashed subpackets:')
268 for subpacket in self['unhashed-subpackets']:
269 lines.append(' {}'.format(subpacket['type']))
270 return '\n'.join(lines)
272 def _str_user_id_packet(self):
275 def from_bytes(self, data):
276 offset = self._parse_header(data=data)
277 packet = data[offset:offset + self['length']]
278 if len(packet) < self['length']:
279 raise ValueError('packet too short ({} < {})'.format(
280 len(packet), self['length']))
281 offset += self['length']
282 method_name = '_parse_{}'.format(self._clean_type())
283 method = getattr(self, method_name, None)
285 raise NotImplementedError(
286 'cannot parse packet type {!r}'.format(self['type']))
290 def _parse_header(self, data):
293 always_one = packet_tag & 1 << 7
295 raise ValueError('most significant packet tag bit not set')
296 self['new-format'] = packet_tag & 1 << 6
297 if self['new-format']:
298 type_code = packet_tag & 0b111111
299 raise NotImplementedError('new-format packet length')
301 type_code = packet_tag >> 2 & 0b1111
302 self['length-type'] = packet_tag & 0b11
303 length_bytes, length_type = self._old_format_packet_length_type[
306 raise NotImplementedError(
307 'old-format packet of indeterminate length')
308 length_format = '>{}'.format(length_type)
309 length_data = data[offset: offset + length_bytes]
310 offset += length_bytes
311 self['length'] = _struct.unpack(length_format, length_data)[0]
312 self['type'] = self._packet_types[type_code]
316 def _parse_multiprecision_integer(data):
317 r"""Parse RFC 4880's multiprecision integers
319 >>> PGPPacket._parse_multiprecision_integer(b'\x00\x01\x01')
321 >>> PGPPacket._parse_multiprecision_integer(b'\x00\x09\x01\xff')
324 bits = _struct.unpack('>H', data[:2])[0]
326 length = (bits + 7) // 8
328 for i in range(length):
329 value += data[offset + i] * 1 << (8 * (length - i - 1))
331 return (offset, value)
333 def _parse_string_to_key_specifier(self, data):
334 self['string-to-key-type'] = self._string_to_key_types[data[0]]
336 if self['string-to-key-type'] == 'simple':
337 self['string-to-key-hash-algorithm'] = self._hash_algorithms[
340 elif self['string-to-key-type'] == 'salted':
341 self['string-to-key-hash-algorithm'] = self._hash_algorithms[
344 self['string-to-key-salt'] = data[offset: offset + 8]
346 elif self['string-to-key-type'] == 'iterated and salted':
347 self['string-to-key-hash-algorithm'] = self._hash_algorithms[
350 self['string-to-key-salt'] = data[offset: offset + 8]
352 self['string-to-key-coded-count'] = data[offset]
355 raise NotImplementedError(
356 'string-to-key type {}'.format(self['string-to-key-type']))
359 def _parse_public_key_packet(self, data):
360 self._parse_generic_public_key_packet(data=data)
362 def _parse_public_subkey_packet(self, data):
363 self._parse_generic_public_key_packet(data=data)
365 def _parse_generic_public_key_packet(self, data):
366 self['key-version'] = data[0]
368 if self['key-version'] != 4:
369 raise NotImplementedError(
370 'public (sub)key packet version {}'.format(
371 self['key-version']))
373 self['creation-time'], algorithm = _struct.unpack(
374 '>IB', data[offset: offset + length])
376 self['public-key-algorithm'] = self._public_key_algorithms[algorithm]
377 if self['public-key-algorithm'].startswith('rsa '):
378 o, self['public-modulus'] = self._parse_multiprecision_integer(
381 o, self['public-exponent'] = self._parse_multiprecision_integer(
384 elif self['public-key-algorithm'].startswith('dsa '):
385 o, self['prime'] = self._parse_multiprecision_integer(
388 o, self['group-order'] = self._parse_multiprecision_integer(
391 o, self['group-generator'] = self._parse_multiprecision_integer(
394 o, self['public-key'] = self._parse_multiprecision_integer(
397 elif self['public-key-algorithm'].startswith('elgamal '):
398 o, self['prime'] = self._parse_multiprecision_integer(
401 o, self['group-generator'] = self._parse_multiprecision_integer(
404 o, self['public-key'] = self._parse_multiprecision_integer(
408 raise NotImplementedError(
409 'algorithm-specific key fields for {}'.format(
410 self['public-key-algorithm']))
411 fingerprint = _hashlib.sha1()
412 fingerprint.update(b'\x99')
413 fingerprint.update(_struct.pack('>H', len(data)))
414 fingerprint.update(data)
415 self['fingerprint'] = fingerprint.hexdigest()
418 def _parse_secret_key_packet(self, data):
419 self._parse_generic_secret_key_packet(data=data)
421 def _parse_secret_subkey_packet(self, data):
422 self._parse_generic_secret_key_packet(data=data)
424 def _parse_generic_secret_key_packet(self, data):
425 offset = self._parse_generic_public_key_packet(data=data)
426 string_to_key_usage = data[offset]
428 if string_to_key_usage in [255, 254]:
429 self['symmetric-encryption-algorithm'] = (
430 self._symmetric_key_algorithms[data[offset]])
432 offset += self._parse_string_to_key_specifier(data=data[offset:])
434 self['symmetric-encryption-algorithm'] = (
435 self._symmetric_key_algorithms[string_to_key_usage])
436 if string_to_key_usage:
437 block_size_bits = self._cipher_block_size.get(
438 self['symmetric-encryption-algorithm'], None)
439 if block_size_bits % 8:
440 raise NotImplementedError(
441 ('{}-bit block size for {} is not an integer number of bytes'
443 block_size_bits, self['symmetric-encryption-algorithm']))
444 block_size = block_size_bits // 8
446 raise NotImplementedError(
447 'unknown block size for {}'.format(
448 self['symmetric-encryption-algorithm']))
449 self['initial-vector'] = data[offset: offset + block_size]
451 if string_to_key_usage in [0, 255]:
455 self['secret-key'] = data[offset:key_end]
457 self['secret-key-checksum'] = data[key_end:]
459 def _parse_signature_subpackets(self, data):
461 while offset < len(data):
462 o, subpacket = self._parse_signature_subpacket(data=data[offset:])
466 def _parse_signature_subpacket(self, data):
472 elif first >= 192 and first < 255:
473 second = data[offset]
475 length = ((first - 192) << 8) + second + 192
477 length = _struct.unpack(
478 '>I', data[offset: offset + 4])[0]
480 subpacket['type'] = self._signature_subpacket_types[data[offset]]
482 subpacket['data'] = data[offset: offset + length - 1]
483 offset += len(subpacket['data'])
484 return (offset, subpacket)
486 def _parse_signature_packet(self, data):
487 self['signature-version'] = data[0]
489 if self['signature-version'] != 4:
490 raise NotImplementedError(
491 'signature packet version {}'.format(
492 self['signature-version']))
493 self['signature-type'] = self._signature_types[data[offset]]
495 self['public-key-algorithm'] = self._public_key_algorithms[
498 self['hash-algorithm'] = self._hash_algorithms[data[offset]]
500 hashed_count = _struct.unpack('>H', data[offset: offset + 2])[0]
502 self['hashed-subpackets'] = data[offset: offset + hashed_count]
503 offset += hashed_count
504 unhashed_count = _struct.unpack('>H', data[offset: offset + 2])[0]
506 self['unhashed-subpackets'] = list(self._parse_signature_subpackets(
507 data=data[offset: offset + unhashed_count]))
508 offset += unhashed_count
509 self['signed-hash-word'] = data[offset: offset + 2]
511 self['signature'] = data[offset:]
513 def _parse_user_id_packet(self, data):
514 self['user'] = str(data, 'utf-8')
520 def packets_from_bytes(data):
522 while offset < len(data):
524 offset += packet.from_bytes(data=data[offset:])
528 class PGPKey (object):
529 def __init__(self, fingerprint):
530 self.fingerprint = fingerprint
531 self.public_packets = None
532 self.secret_packets = None
535 lines = ['key: {}'.format(self.fingerprint)]
536 if self.public_packets:
537 lines.append(' public:')
538 for packet in self.public_packets:
539 lines.extend(self._str_packet(packet=packet, prefix=' '))
540 if self.secret_packets:
541 lines.append(' secret:')
542 for packet in self.secret_packets:
543 lines.extend(self._str_packet(packet=packet, prefix=' '))
544 return '\n'.join(lines)
546 def _str_packet(self, packet, prefix):
547 lines = str(packet).split('\n')
548 return [prefix + line for line in lines]
550 def import_from_gpg(self):
551 key_export = _get_stdout(
552 ['gpg', '--export', self.fingerprint])
553 self.public_packets = list(
554 packets_from_bytes(data=key_export))
555 if self.public_packets[0]['type'] != 'public-key packet':
557 '{} does not start with a public-key packet'.format(
559 key_secret_export = _get_stdout(
560 ['gpg', '--export-secret-keys', self.fingerprint])
561 self.secret_packets = list(
562 packets_from_bytes(data=key_secret_export))
564 def export_to_gpg(self):
565 raise NotImplemetedError('export to gpg')
567 def import_from_key(self, key):
568 """Migrate the (sub)keys into this key"""
572 def migrate(old_key, new_key):
573 """Add the old key and sub-keys to the new key
575 For example, to upgrade your master key, while preserving old
576 signatures you'd made. You will lose signature *on* your old key
577 though, since sub-keys can't be signed (I don't think).
579 old_key = PGPKey(fingerprint=old_key)
580 old_key.import_from_gpg()
581 new_key = PGPKey(fingerprint=new_key)
582 new_key.import_from_gpg()
583 new_key.import_from_key(key=old_key)
589 if __name__ == '__main__':
592 old_key, new_key = _sys.argv[1:3]
593 migrate(old_key=old_key, new_key=new_key)