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- # coding: utf-8
- """
- ASN.1 type classes for public and private keys. Exports the following items:
- - DSAPrivateKey()
- - ECPrivateKey()
- - EncryptedPrivateKeyInfo()
- - PrivateKeyInfo()
- - PublicKeyInfo()
- - RSAPrivateKey()
- - RSAPublicKey()
- Other type classes are defined that help compose the types listed above.
- """
- from __future__ import unicode_literals, division, absolute_import, print_function
- import hashlib
- import math
- from ._elliptic_curve import (
- SECP192R1_BASE_POINT,
- SECP224R1_BASE_POINT,
- SECP256R1_BASE_POINT,
- SECP384R1_BASE_POINT,
- SECP521R1_BASE_POINT,
- PrimeCurve,
- PrimePoint,
- )
- from ._errors import unwrap
- from ._types import type_name, str_cls, byte_cls
- from .algos import _ForceNullParameters, DigestAlgorithm, EncryptionAlgorithm, RSAESOAEPParams
- from .core import (
- Any,
- Asn1Value,
- BitString,
- Choice,
- Integer,
- IntegerOctetString,
- Null,
- ObjectIdentifier,
- OctetBitString,
- OctetString,
- ParsableOctetString,
- ParsableOctetBitString,
- Sequence,
- SequenceOf,
- SetOf,
- )
- from .util import int_from_bytes, int_to_bytes
- class OtherPrimeInfo(Sequence):
- """
- Source: https://tools.ietf.org/html/rfc3447#page-46
- """
- _fields = [
- ('prime', Integer),
- ('exponent', Integer),
- ('coefficient', Integer),
- ]
- class OtherPrimeInfos(SequenceOf):
- """
- Source: https://tools.ietf.org/html/rfc3447#page-46
- """
- _child_spec = OtherPrimeInfo
- class RSAPrivateKeyVersion(Integer):
- """
- Original Name: Version
- Source: https://tools.ietf.org/html/rfc3447#page-45
- """
- _map = {
- 0: 'two-prime',
- 1: 'multi',
- }
- class RSAPrivateKey(Sequence):
- """
- Source: https://tools.ietf.org/html/rfc3447#page-45
- """
- _fields = [
- ('version', RSAPrivateKeyVersion),
- ('modulus', Integer),
- ('public_exponent', Integer),
- ('private_exponent', Integer),
- ('prime1', Integer),
- ('prime2', Integer),
- ('exponent1', Integer),
- ('exponent2', Integer),
- ('coefficient', Integer),
- ('other_prime_infos', OtherPrimeInfos, {'optional': True})
- ]
- class RSAPublicKey(Sequence):
- """
- Source: https://tools.ietf.org/html/rfc3447#page-44
- """
- _fields = [
- ('modulus', Integer),
- ('public_exponent', Integer)
- ]
- class DSAPrivateKey(Sequence):
- """
- The ASN.1 structure that OpenSSL uses to store a DSA private key that is
- not part of a PKCS#8 structure. Reversed engineered from english-language
- description on linked OpenSSL documentation page.
- Original Name: None
- Source: https://www.openssl.org/docs/apps/dsa.html
- """
- _fields = [
- ('version', Integer),
- ('p', Integer),
- ('q', Integer),
- ('g', Integer),
- ('public_key', Integer),
- ('private_key', Integer),
- ]
- class _ECPoint():
- """
- In both PublicKeyInfo and PrivateKeyInfo, the EC public key is a byte
- string that is encoded as a bit string. This class adds convenience
- methods for converting to and from the byte string to a pair of integers
- that are the X and Y coordinates.
- """
- @classmethod
- def from_coords(cls, x, y):
- """
- Creates an ECPoint object from the X and Y integer coordinates of the
- point
- :param x:
- The X coordinate, as an integer
- :param y:
- The Y coordinate, as an integer
- :return:
- An ECPoint object
- """
- x_bytes = int(math.ceil(math.log(x, 2) / 8.0))
- y_bytes = int(math.ceil(math.log(y, 2) / 8.0))
- num_bytes = max(x_bytes, y_bytes)
- byte_string = b'\x04'
- byte_string += int_to_bytes(x, width=num_bytes)
- byte_string += int_to_bytes(y, width=num_bytes)
- return cls(byte_string)
- def to_coords(self):
- """
- Returns the X and Y coordinates for this EC point, as native Python
- integers
- :return:
- A 2-element tuple containing integers (X, Y)
- """
- data = self.native
- first_byte = data[0:1]
- # Uncompressed
- if first_byte == b'\x04':
- remaining = data[1:]
- field_len = len(remaining) // 2
- x = int_from_bytes(remaining[0:field_len])
- y = int_from_bytes(remaining[field_len:])
- return (x, y)
- if first_byte not in set([b'\x02', b'\x03']):
- raise ValueError(unwrap(
- '''
- Invalid EC public key - first byte is incorrect
- '''
- ))
- raise ValueError(unwrap(
- '''
- Compressed representations of EC public keys are not supported due
- to patent US6252960
- '''
- ))
- class ECPoint(OctetString, _ECPoint):
- pass
- class ECPointBitString(OctetBitString, _ECPoint):
- pass
- class SpecifiedECDomainVersion(Integer):
- """
- Source: http://www.secg.org/sec1-v2.pdf page 104
- """
- _map = {
- 1: 'ecdpVer1',
- 2: 'ecdpVer2',
- 3: 'ecdpVer3',
- }
- class FieldType(ObjectIdentifier):
- """
- Original Name: None
- Source: http://www.secg.org/sec1-v2.pdf page 101
- """
- _map = {
- '1.2.840.10045.1.1': 'prime_field',
- '1.2.840.10045.1.2': 'characteristic_two_field',
- }
- class CharacteristicTwoBasis(ObjectIdentifier):
- """
- Original Name: None
- Source: http://www.secg.org/sec1-v2.pdf page 102
- """
- _map = {
- '1.2.840.10045.1.2.1.1': 'gn_basis',
- '1.2.840.10045.1.2.1.2': 'tp_basis',
- '1.2.840.10045.1.2.1.3': 'pp_basis',
- }
- class Pentanomial(Sequence):
- """
- Source: http://www.secg.org/sec1-v2.pdf page 102
- """
- _fields = [
- ('k1', Integer),
- ('k2', Integer),
- ('k3', Integer),
- ]
- class CharacteristicTwo(Sequence):
- """
- Original Name: Characteristic-two
- Source: http://www.secg.org/sec1-v2.pdf page 101
- """
- _fields = [
- ('m', Integer),
- ('basis', CharacteristicTwoBasis),
- ('parameters', Any),
- ]
- _oid_pair = ('basis', 'parameters')
- _oid_specs = {
- 'gn_basis': Null,
- 'tp_basis': Integer,
- 'pp_basis': Pentanomial,
- }
- class FieldID(Sequence):
- """
- Source: http://www.secg.org/sec1-v2.pdf page 100
- """
- _fields = [
- ('field_type', FieldType),
- ('parameters', Any),
- ]
- _oid_pair = ('field_type', 'parameters')
- _oid_specs = {
- 'prime_field': Integer,
- 'characteristic_two_field': CharacteristicTwo,
- }
- class Curve(Sequence):
- """
- Source: http://www.secg.org/sec1-v2.pdf page 104
- """
- _fields = [
- ('a', OctetString),
- ('b', OctetString),
- ('seed', OctetBitString, {'optional': True}),
- ]
- class SpecifiedECDomain(Sequence):
- """
- Source: http://www.secg.org/sec1-v2.pdf page 103
- """
- _fields = [
- ('version', SpecifiedECDomainVersion),
- ('field_id', FieldID),
- ('curve', Curve),
- ('base', ECPoint),
- ('order', Integer),
- ('cofactor', Integer, {'optional': True}),
- ('hash', DigestAlgorithm, {'optional': True}),
- ]
- class NamedCurve(ObjectIdentifier):
- """
- Various named curves
- Original Name: None
- Source: https://tools.ietf.org/html/rfc3279#page-23,
- https://tools.ietf.org/html/rfc5480#page-5
- """
- _map = {
- # https://tools.ietf.org/html/rfc3279#page-23
- '1.2.840.10045.3.0.1': 'c2pnb163v1',
- '1.2.840.10045.3.0.2': 'c2pnb163v2',
- '1.2.840.10045.3.0.3': 'c2pnb163v3',
- '1.2.840.10045.3.0.4': 'c2pnb176w1',
- '1.2.840.10045.3.0.5': 'c2tnb191v1',
- '1.2.840.10045.3.0.6': 'c2tnb191v2',
- '1.2.840.10045.3.0.7': 'c2tnb191v3',
- '1.2.840.10045.3.0.8': 'c2onb191v4',
- '1.2.840.10045.3.0.9': 'c2onb191v5',
- '1.2.840.10045.3.0.10': 'c2pnb208w1',
- '1.2.840.10045.3.0.11': 'c2tnb239v1',
- '1.2.840.10045.3.0.12': 'c2tnb239v2',
- '1.2.840.10045.3.0.13': 'c2tnb239v3',
- '1.2.840.10045.3.0.14': 'c2onb239v4',
- '1.2.840.10045.3.0.15': 'c2onb239v5',
- '1.2.840.10045.3.0.16': 'c2pnb272w1',
- '1.2.840.10045.3.0.17': 'c2pnb304w1',
- '1.2.840.10045.3.0.18': 'c2tnb359v1',
- '1.2.840.10045.3.0.19': 'c2pnb368w1',
- '1.2.840.10045.3.0.20': 'c2tnb431r1',
- '1.2.840.10045.3.1.2': 'prime192v2',
- '1.2.840.10045.3.1.3': 'prime192v3',
- '1.2.840.10045.3.1.4': 'prime239v1',
- '1.2.840.10045.3.1.5': 'prime239v2',
- '1.2.840.10045.3.1.6': 'prime239v3',
- # https://tools.ietf.org/html/rfc5480#page-5
- '1.3.132.0.1': 'sect163k1',
- '1.3.132.0.15': 'sect163r2',
- '1.2.840.10045.3.1.1': 'secp192r1',
- '1.3.132.0.33': 'secp224r1',
- '1.3.132.0.26': 'sect233k1',
- '1.2.840.10045.3.1.7': 'secp256r1',
- '1.3.132.0.27': 'sect233r1',
- '1.3.132.0.16': 'sect283k1',
- '1.3.132.0.17': 'sect283r1',
- '1.3.132.0.34': 'secp384r1',
- '1.3.132.0.36': 'sect409k1',
- '1.3.132.0.37': 'sect409r1',
- '1.3.132.0.35': 'secp521r1',
- '1.3.132.0.38': 'sect571k1',
- '1.3.132.0.39': 'sect571r1',
- }
- class ECDomainParameters(Choice):
- """
- Source: http://www.secg.org/sec1-v2.pdf page 102
- """
- _alternatives = [
- ('specified', SpecifiedECDomain),
- ('named', NamedCurve),
- ('implicit_ca', Null),
- ]
- class ECPrivateKeyVersion(Integer):
- """
- Original Name: None
- Source: http://www.secg.org/sec1-v2.pdf page 108
- """
- _map = {
- 1: 'ecPrivkeyVer1',
- }
- class ECPrivateKey(Sequence):
- """
- Source: http://www.secg.org/sec1-v2.pdf page 108
- """
- _fields = [
- ('version', ECPrivateKeyVersion),
- ('private_key', IntegerOctetString),
- ('parameters', ECDomainParameters, {'explicit': 0, 'optional': True}),
- ('public_key', ECPointBitString, {'explicit': 1, 'optional': True}),
- ]
- class DSAParams(Sequence):
- """
- Parameters for a DSA public or private key
- Original Name: Dss-Parms
- Source: https://tools.ietf.org/html/rfc3279#page-9
- """
- _fields = [
- ('p', Integer),
- ('q', Integer),
- ('g', Integer),
- ]
- class Attribute(Sequence):
- """
- Source: https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-X.501-198811-S!!PDF-E&type=items page 8
- """
- _fields = [
- ('type', ObjectIdentifier),
- ('values', SetOf, {'spec': Any}),
- ]
- class Attributes(SetOf):
- """
- Source: https://tools.ietf.org/html/rfc5208#page-3
- """
- _child_spec = Attribute
- class PrivateKeyAlgorithmId(ObjectIdentifier):
- """
- These OIDs for various public keys are reused when storing private keys
- inside of a PKCS#8 structure
- Original Name: None
- Source: https://tools.ietf.org/html/rfc3279
- """
- _map = {
- # https://tools.ietf.org/html/rfc3279#page-19
- '1.2.840.113549.1.1.1': 'rsa',
- # https://tools.ietf.org/html/rfc3279#page-18
- '1.2.840.10040.4.1': 'dsa',
- # https://tools.ietf.org/html/rfc3279#page-13
- '1.2.840.10045.2.1': 'ec',
- }
- class PrivateKeyAlgorithm(_ForceNullParameters, Sequence):
- """
- Original Name: PrivateKeyAlgorithmIdentifier
- Source: https://tools.ietf.org/html/rfc5208#page-3
- """
- _fields = [
- ('algorithm', PrivateKeyAlgorithmId),
- ('parameters', Any, {'optional': True}),
- ]
- _oid_pair = ('algorithm', 'parameters')
- _oid_specs = {
- 'dsa': DSAParams,
- 'ec': ECDomainParameters,
- }
- class PrivateKeyInfo(Sequence):
- """
- Source: https://tools.ietf.org/html/rfc5208#page-3
- """
- _fields = [
- ('version', Integer),
- ('private_key_algorithm', PrivateKeyAlgorithm),
- ('private_key', ParsableOctetString),
- ('attributes', Attributes, {'implicit': 0, 'optional': True}),
- ]
- def _private_key_spec(self):
- algorithm = self['private_key_algorithm']['algorithm'].native
- return {
- 'rsa': RSAPrivateKey,
- 'dsa': Integer,
- 'ec': ECPrivateKey,
- }[algorithm]
- _spec_callbacks = {
- 'private_key': _private_key_spec
- }
- _algorithm = None
- _bit_size = None
- _public_key = None
- _fingerprint = None
- @classmethod
- def wrap(cls, private_key, algorithm):
- """
- Wraps a private key in a PrivateKeyInfo structure
- :param private_key:
- A byte string or Asn1Value object of the private key
- :param algorithm:
- A unicode string of "rsa", "dsa" or "ec"
- :return:
- A PrivateKeyInfo object
- """
- if not isinstance(private_key, byte_cls) and not isinstance(private_key, Asn1Value):
- raise TypeError(unwrap(
- '''
- private_key must be a byte string or Asn1Value, not %s
- ''',
- type_name(private_key)
- ))
- if algorithm == 'rsa':
- if not isinstance(private_key, RSAPrivateKey):
- private_key = RSAPrivateKey.load(private_key)
- params = Null()
- elif algorithm == 'dsa':
- if not isinstance(private_key, DSAPrivateKey):
- private_key = DSAPrivateKey.load(private_key)
- params = DSAParams()
- params['p'] = private_key['p']
- params['q'] = private_key['q']
- params['g'] = private_key['g']
- public_key = private_key['public_key']
- private_key = private_key['private_key']
- elif algorithm == 'ec':
- if not isinstance(private_key, ECPrivateKey):
- private_key = ECPrivateKey.load(private_key)
- else:
- private_key = private_key.copy()
- params = private_key['parameters']
- del private_key['parameters']
- else:
- raise ValueError(unwrap(
- '''
- algorithm must be one of "rsa", "dsa", "ec", not %s
- ''',
- repr(algorithm)
- ))
- private_key_algo = PrivateKeyAlgorithm()
- private_key_algo['algorithm'] = PrivateKeyAlgorithmId(algorithm)
- private_key_algo['parameters'] = params
- container = cls()
- container._algorithm = algorithm
- container['version'] = Integer(0)
- container['private_key_algorithm'] = private_key_algo
- container['private_key'] = private_key
- # Here we save the DSA public key if possible since it is not contained
- # within the PKCS#8 structure for a DSA key
- if algorithm == 'dsa':
- container._public_key = public_key
- return container
- def _compute_public_key(self):
- """
- Computes the public key corresponding to the current private key.
- :return:
- For RSA keys, an RSAPublicKey object. For DSA keys, an Integer
- object. For EC keys, an ECPointBitString.
- """
- if self.algorithm == 'dsa':
- params = self['private_key_algorithm']['parameters']
- return Integer(pow(
- params['g'].native,
- self['private_key'].parsed.native,
- params['p'].native
- ))
- if self.algorithm == 'rsa':
- key = self['private_key'].parsed
- return RSAPublicKey({
- 'modulus': key['modulus'],
- 'public_exponent': key['public_exponent'],
- })
- if self.algorithm == 'ec':
- curve_type, details = self.curve
- if curve_type == 'implicit_ca':
- raise ValueError(unwrap(
- '''
- Unable to compute public key for EC key using Implicit CA
- parameters
- '''
- ))
- if curve_type == 'specified':
- if details['field_id']['field_type'] == 'characteristic_two_field':
- raise ValueError(unwrap(
- '''
- Unable to compute public key for EC key over a
- characteristic two field
- '''
- ))
- curve = PrimeCurve(
- details['field_id']['parameters'],
- int_from_bytes(details['curve']['a']),
- int_from_bytes(details['curve']['b'])
- )
- base_x, base_y = self['private_key_algorithm']['parameters'].chosen['base'].to_coords()
- base_point = PrimePoint(curve, base_x, base_y)
- elif curve_type == 'named':
- if details not in ('secp192r1', 'secp224r1', 'secp256r1', 'secp384r1', 'secp521r1'):
- raise ValueError(unwrap(
- '''
- Unable to compute public key for EC named curve %s,
- parameters not currently included
- ''',
- details
- ))
- base_point = {
- 'secp192r1': SECP192R1_BASE_POINT,
- 'secp224r1': SECP224R1_BASE_POINT,
- 'secp256r1': SECP256R1_BASE_POINT,
- 'secp384r1': SECP384R1_BASE_POINT,
- 'secp521r1': SECP521R1_BASE_POINT,
- }[details]
- public_point = base_point * self['private_key'].parsed['private_key'].native
- return ECPointBitString.from_coords(public_point.x, public_point.y)
- def unwrap(self):
- """
- Unwraps the private key into an RSAPrivateKey, DSAPrivateKey or
- ECPrivateKey object
- :return:
- An RSAPrivateKey, DSAPrivateKey or ECPrivateKey object
- """
- if self.algorithm == 'rsa':
- return self['private_key'].parsed
- if self.algorithm == 'dsa':
- params = self['private_key_algorithm']['parameters']
- return DSAPrivateKey({
- 'version': 0,
- 'p': params['p'],
- 'q': params['q'],
- 'g': params['g'],
- 'public_key': self.public_key,
- 'private_key': self['private_key'].parsed,
- })
- if self.algorithm == 'ec':
- output = self['private_key'].parsed
- output['parameters'] = self['private_key_algorithm']['parameters']
- output['public_key'] = self.public_key
- return output
- @property
- def curve(self):
- """
- Returns information about the curve used for an EC key
- :raises:
- ValueError - when the key is not an EC key
- :return:
- A two-element tuple, with the first element being a unicode string
- of "implicit_ca", "specified" or "named". If the first element is
- "implicit_ca", the second is None. If "specified", the second is
- an OrderedDict that is the native version of SpecifiedECDomain. If
- "named", the second is a unicode string of the curve name.
- """
- if self.algorithm != 'ec':
- raise ValueError(unwrap(
- '''
- Only EC keys have a curve, this key is %s
- ''',
- self.algorithm.upper()
- ))
- params = self['private_key_algorithm']['parameters']
- chosen = params.chosen
- if params.name == 'implicit_ca':
- value = None
- else:
- value = chosen.native
- return (params.name, value)
- @property
- def hash_algo(self):
- """
- Returns the name of the family of hash algorithms used to generate a
- DSA key
- :raises:
- ValueError - when the key is not a DSA key
- :return:
- A unicode string of "sha1" or "sha2"
- """
- if self.algorithm != 'dsa':
- raise ValueError(unwrap(
- '''
- Only DSA keys are generated using a hash algorithm, this key is
- %s
- ''',
- self.algorithm.upper()
- ))
- byte_len = math.log(self['private_key_algorithm']['parameters']['q'].native, 2) / 8
- return 'sha1' if byte_len <= 20 else 'sha2'
- @property
- def algorithm(self):
- """
- :return:
- A unicode string of "rsa", "dsa" or "ec"
- """
- if self._algorithm is None:
- self._algorithm = self['private_key_algorithm']['algorithm'].native
- return self._algorithm
- @property
- def bit_size(self):
- """
- :return:
- The bit size of the private key, as an integer
- """
- if self._bit_size is None:
- if self.algorithm == 'rsa':
- prime = self['private_key'].parsed['modulus'].native
- elif self.algorithm == 'dsa':
- prime = self['private_key_algorithm']['parameters']['p'].native
- elif self.algorithm == 'ec':
- prime = self['private_key'].parsed['private_key'].native
- self._bit_size = int(math.ceil(math.log(prime, 2)))
- modulus = self._bit_size % 8
- if modulus != 0:
- self._bit_size += 8 - modulus
- return self._bit_size
- @property
- def byte_size(self):
- """
- :return:
- The byte size of the private key, as an integer
- """
- return int(math.ceil(self.bit_size / 8))
- @property
- def public_key(self):
- """
- :return:
- If an RSA key, an RSAPublicKey object. If a DSA key, an Integer
- object. If an EC key, an ECPointBitString object.
- """
- if self._public_key is None:
- if self.algorithm == 'ec':
- key = self['private_key'].parsed
- if key['public_key']:
- self._public_key = key['public_key'].untag()
- else:
- self._public_key = self._compute_public_key()
- else:
- self._public_key = self._compute_public_key()
- return self._public_key
- @property
- def public_key_info(self):
- """
- :return:
- A PublicKeyInfo object derived from this private key.
- """
- return PublicKeyInfo({
- 'algorithm': {
- 'algorithm': self.algorithm,
- 'parameters': self['private_key_algorithm']['parameters']
- },
- 'public_key': self.public_key
- })
- @property
- def fingerprint(self):
- """
- Creates a fingerprint that can be compared with a public key to see if
- the two form a pair.
- This fingerprint is not compatible with fingerprints generated by any
- other software.
- :return:
- A byte string that is a sha256 hash of selected components (based
- on the key type)
- """
- if self._fingerprint is None:
- params = self['private_key_algorithm']['parameters']
- key = self['private_key'].parsed
- if self.algorithm == 'rsa':
- to_hash = '%d:%d' % (
- key['modulus'].native,
- key['public_exponent'].native,
- )
- elif self.algorithm == 'dsa':
- public_key = self.public_key
- to_hash = '%d:%d:%d:%d' % (
- params['p'].native,
- params['q'].native,
- params['g'].native,
- public_key.native,
- )
- elif self.algorithm == 'ec':
- public_key = key['public_key'].native
- if public_key is None:
- public_key = self.public_key.native
- if params.name == 'named':
- to_hash = '%s:' % params.chosen.native
- to_hash = to_hash.encode('utf-8')
- to_hash += public_key
- elif params.name == 'implicit_ca':
- to_hash = public_key
- elif params.name == 'specified':
- to_hash = '%s:' % params.chosen['field_id']['parameters'].native
- to_hash = to_hash.encode('utf-8')
- to_hash += b':' + params.chosen['curve']['a'].native
- to_hash += b':' + params.chosen['curve']['b'].native
- to_hash += public_key
- if isinstance(to_hash, str_cls):
- to_hash = to_hash.encode('utf-8')
- self._fingerprint = hashlib.sha256(to_hash).digest()
- return self._fingerprint
- class EncryptedPrivateKeyInfo(Sequence):
- """
- Source: https://tools.ietf.org/html/rfc5208#page-4
- """
- _fields = [
- ('encryption_algorithm', EncryptionAlgorithm),
- ('encrypted_data', OctetString),
- ]
- # These structures are from https://tools.ietf.org/html/rfc3279
- class ValidationParms(Sequence):
- """
- Source: https://tools.ietf.org/html/rfc3279#page-10
- """
- _fields = [
- ('seed', BitString),
- ('pgen_counter', Integer),
- ]
- class DomainParameters(Sequence):
- """
- Source: https://tools.ietf.org/html/rfc3279#page-10
- """
- _fields = [
- ('p', Integer),
- ('g', Integer),
- ('q', Integer),
- ('j', Integer, {'optional': True}),
- ('validation_params', ValidationParms, {'optional': True}),
- ]
- class PublicKeyAlgorithmId(ObjectIdentifier):
- """
- Original Name: None
- Source: https://tools.ietf.org/html/rfc3279
- """
- _map = {
- # https://tools.ietf.org/html/rfc3279#page-19
- '1.2.840.113549.1.1.1': 'rsa',
- # https://tools.ietf.org/html/rfc3447#page-47
- '1.2.840.113549.1.1.7': 'rsaes_oaep',
- # https://tools.ietf.org/html/rfc3279#page-18
- '1.2.840.10040.4.1': 'dsa',
- # https://tools.ietf.org/html/rfc3279#page-13
- '1.2.840.10045.2.1': 'ec',
- # https://tools.ietf.org/html/rfc3279#page-10
- '1.2.840.10046.2.1': 'dh',
- }
- class PublicKeyAlgorithm(_ForceNullParameters, Sequence):
- """
- Original Name: AlgorithmIdentifier
- Source: https://tools.ietf.org/html/rfc5280#page-18
- """
- _fields = [
- ('algorithm', PublicKeyAlgorithmId),
- ('parameters', Any, {'optional': True}),
- ]
- _oid_pair = ('algorithm', 'parameters')
- _oid_specs = {
- 'dsa': DSAParams,
- 'ec': ECDomainParameters,
- 'dh': DomainParameters,
- 'rsaes_oaep': RSAESOAEPParams,
- }
- class PublicKeyInfo(Sequence):
- """
- Original Name: SubjectPublicKeyInfo
- Source: https://tools.ietf.org/html/rfc5280#page-17
- """
- _fields = [
- ('algorithm', PublicKeyAlgorithm),
- ('public_key', ParsableOctetBitString),
- ]
- def _public_key_spec(self):
- algorithm = self['algorithm']['algorithm'].native
- return {
- 'rsa': RSAPublicKey,
- 'rsaes_oaep': RSAPublicKey,
- 'dsa': Integer,
- # We override the field spec with ECPoint so that users can easily
- # decompose the byte string into the constituent X and Y coords
- 'ec': (ECPointBitString, None),
- 'dh': Integer,
- }[algorithm]
- _spec_callbacks = {
- 'public_key': _public_key_spec
- }
- _algorithm = None
- _bit_size = None
- _fingerprint = None
- _sha1 = None
- _sha256 = None
- @classmethod
- def wrap(cls, public_key, algorithm):
- """
- Wraps a public key in a PublicKeyInfo structure
- :param public_key:
- A byte string or Asn1Value object of the public key
- :param algorithm:
- A unicode string of "rsa"
- :return:
- A PublicKeyInfo object
- """
- if not isinstance(public_key, byte_cls) and not isinstance(public_key, Asn1Value):
- raise TypeError(unwrap(
- '''
- public_key must be a byte string or Asn1Value, not %s
- ''',
- type_name(public_key)
- ))
- if algorithm != 'rsa':
- raise ValueError(unwrap(
- '''
- algorithm must "rsa", not %s
- ''',
- repr(algorithm)
- ))
- algo = PublicKeyAlgorithm()
- algo['algorithm'] = PublicKeyAlgorithmId(algorithm)
- algo['parameters'] = Null()
- container = cls()
- container['algorithm'] = algo
- if isinstance(public_key, Asn1Value):
- public_key = public_key.untag().dump()
- container['public_key'] = ParsableOctetBitString(public_key)
- return container
- def unwrap(self):
- """
- Unwraps an RSA public key into an RSAPublicKey object. Does not support
- DSA or EC public keys since they do not have an unwrapped form.
- :return:
- An RSAPublicKey object
- """
- if self.algorithm == 'rsa':
- return self['public_key'].parsed
- key_type = self.algorithm.upper()
- a_an = 'an' if key_type == 'EC' else 'a'
- raise ValueError(unwrap(
- '''
- Only RSA public keys may be unwrapped - this key is %s %s public
- key
- ''',
- a_an,
- key_type
- ))
- @property
- def curve(self):
- """
- Returns information about the curve used for an EC key
- :raises:
- ValueError - when the key is not an EC key
- :return:
- A two-element tuple, with the first element being a unicode string
- of "implicit_ca", "specified" or "named". If the first element is
- "implicit_ca", the second is None. If "specified", the second is
- an OrderedDict that is the native version of SpecifiedECDomain. If
- "named", the second is a unicode string of the curve name.
- """
- if self.algorithm != 'ec':
- raise ValueError(unwrap(
- '''
- Only EC keys have a curve, this key is %s
- ''',
- self.algorithm.upper()
- ))
- params = self['algorithm']['parameters']
- chosen = params.chosen
- if params.name == 'implicit_ca':
- value = None
- else:
- value = chosen.native
- return (params.name, value)
- @property
- def hash_algo(self):
- """
- Returns the name of the family of hash algorithms used to generate a
- DSA key
- :raises:
- ValueError - when the key is not a DSA key
- :return:
- A unicode string of "sha1" or "sha2" or None if no parameters are
- present
- """
- if self.algorithm != 'dsa':
- raise ValueError(unwrap(
- '''
- Only DSA keys are generated using a hash algorithm, this key is
- %s
- ''',
- self.algorithm.upper()
- ))
- parameters = self['algorithm']['parameters']
- if parameters.native is None:
- return None
- byte_len = math.log(parameters['q'].native, 2) / 8
- return 'sha1' if byte_len <= 20 else 'sha2'
- @property
- def algorithm(self):
- """
- :return:
- A unicode string of "rsa", "dsa" or "ec"
- """
- if self._algorithm is None:
- self._algorithm = self['algorithm']['algorithm'].native
- return self._algorithm
- @property
- def bit_size(self):
- """
- :return:
- The bit size of the public key, as an integer
- """
- if self._bit_size is None:
- if self.algorithm == 'ec':
- self._bit_size = ((len(self['public_key'].native) - 1) / 2) * 8
- else:
- if self.algorithm == 'rsa':
- prime = self['public_key'].parsed['modulus'].native
- elif self.algorithm == 'dsa':
- prime = self['algorithm']['parameters']['p'].native
- self._bit_size = int(math.ceil(math.log(prime, 2)))
- modulus = self._bit_size % 8
- if modulus != 0:
- self._bit_size += 8 - modulus
- return self._bit_size
- @property
- def byte_size(self):
- """
- :return:
- The byte size of the public key, as an integer
- """
- return int(math.ceil(self.bit_size / 8))
- @property
- def sha1(self):
- """
- :return:
- The SHA1 hash of the DER-encoded bytes of this public key info
- """
- if self._sha1 is None:
- self._sha1 = hashlib.sha1(byte_cls(self['public_key'])).digest()
- return self._sha1
- @property
- def sha256(self):
- """
- :return:
- The SHA-256 hash of the DER-encoded bytes of this public key info
- """
- if self._sha256 is None:
- self._sha256 = hashlib.sha256(byte_cls(self['public_key'])).digest()
- return self._sha256
- @property
- def fingerprint(self):
- """
- Creates a fingerprint that can be compared with a private key to see if
- the two form a pair.
- This fingerprint is not compatible with fingerprints generated by any
- other software.
- :return:
- A byte string that is a sha256 hash of selected components (based
- on the key type)
- """
- if self._fingerprint is None:
- key_type = self['algorithm']['algorithm'].native
- params = self['algorithm']['parameters']
- if key_type == 'rsa':
- key = self['public_key'].parsed
- to_hash = '%d:%d' % (
- key['modulus'].native,
- key['public_exponent'].native,
- )
- elif key_type == 'dsa':
- key = self['public_key'].parsed
- to_hash = '%d:%d:%d:%d' % (
- params['p'].native,
- params['q'].native,
- params['g'].native,
- key.native,
- )
- elif key_type == 'ec':
- key = self['public_key']
- if params.name == 'named':
- to_hash = '%s:' % params.chosen.native
- to_hash = to_hash.encode('utf-8')
- to_hash += key.native
- elif params.name == 'implicit_ca':
- to_hash = key.native
- elif params.name == 'specified':
- to_hash = '%s:' % params.chosen['field_id']['parameters'].native
- to_hash = to_hash.encode('utf-8')
- to_hash += b':' + params.chosen['curve']['a'].native
- to_hash += b':' + params.chosen['curve']['b'].native
- to_hash += key.native
- if isinstance(to_hash, str_cls):
- to_hash = to_hash.encode('utf-8')
- self._fingerprint = hashlib.sha256(to_hash).digest()
- return self._fingerprint
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