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openmedialibrary_platform_d.../lib/python3.7/site-packages/asn1crypto/algos.py
j 80c4a755da update to python3.7
2019-01-01 00:25:26 +01:00

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# coding: utf-8
"""
ASN.1 type classes for various algorithms using in various aspects of public
key cryptography. Exports the following items:
- AlgorithmIdentifier()
- AnyAlgorithmIdentifier()
- DigestAlgorithm()
- DigestInfo()
- DSASignature()
- EncryptionAlgorithm()
- HmacAlgorithm()
- KdfAlgorithm()
- Pkcs5MacAlgorithm()
- SignedDigestAlgorithm()
Other type classes are defined that help compose the types listed above.
"""
from __future__ import unicode_literals, division, absolute_import, print_function
from ._errors import unwrap
from ._int import fill_width
from .util import int_from_bytes, int_to_bytes
from .core import (
Any,
Choice,
Integer,
Null,
ObjectIdentifier,
OctetString,
Sequence,
Void,
)
# Structures and OIDs in this file are pulled from
# https://tools.ietf.org/html/rfc3279, https://tools.ietf.org/html/rfc4055,
# https://tools.ietf.org/html/rfc5758, https://tools.ietf.org/html/rfc7292,
# http://www.emc.com/collateral/white-papers/h11302-pkcs5v2-1-password-based-cryptography-standard-wp.pdf
class AlgorithmIdentifier(Sequence):
_fields = [
('algorithm', ObjectIdentifier),
('parameters', Any, {'optional': True}),
]
class _ForceNullParameters(object):
"""
Various structures based on AlgorithmIdentifier require that the parameters
field be core.Null() for certain OIDs. This mixin ensures that happens.
"""
# The following attribute, plus the parameters spec callback and custom
# __setitem__ are all to handle a situation where parameters should not be
# optional and must be Null for certain OIDs. More info at
# https://tools.ietf.org/html/rfc4055#page-15 and
# https://tools.ietf.org/html/rfc4055#section-2.1
_null_algos = set([
'1.2.840.113549.1.1.1', # rsassa_pkcs1v15 / rsaes_pkcs1v15 / rsa
'1.2.840.113549.1.1.11', # sha256_rsa
'1.2.840.113549.1.1.12', # sha384_rsa
'1.2.840.113549.1.1.13', # sha512_rsa
'1.2.840.113549.1.1.14', # sha224_rsa
'1.3.14.3.2.26', # sha1
'2.16.840.1.101.3.4.2.4', # sha224
'2.16.840.1.101.3.4.2.1', # sha256
'2.16.840.1.101.3.4.2.2', # sha384
'2.16.840.1.101.3.4.2.3', # sha512
])
def _parameters_spec(self):
if self._oid_pair == ('algorithm', 'parameters'):
algo = self['algorithm'].native
if algo in self._oid_specs:
return self._oid_specs[algo]
if self['algorithm'].dotted in self._null_algos:
return Null
return None
_spec_callbacks = {
'parameters': _parameters_spec
}
# We have to override this since the spec callback uses the value of
# algorithm to determine the parameter spec, however default values are
# assigned before setting a field, so a default value can't be based on
# another field value (unless it is a default also). Thus we have to
# manually check to see if the algorithm was set and parameters is unset,
# and then fix the value as appropriate.
def __setitem__(self, key, value):
res = super(_ForceNullParameters, self).__setitem__(key, value)
if key != 'algorithm':
return res
if self['algorithm'].dotted not in self._null_algos:
return res
if self['parameters'].__class__ != Void:
return res
self['parameters'] = Null()
return res
class HmacAlgorithmId(ObjectIdentifier):
_map = {
'1.3.14.3.2.10': 'des_mac',
'1.2.840.113549.2.7': 'sha1',
'1.2.840.113549.2.8': 'sha224',
'1.2.840.113549.2.9': 'sha256',
'1.2.840.113549.2.10': 'sha384',
'1.2.840.113549.2.11': 'sha512',
'1.2.840.113549.2.12': 'sha512_224',
'1.2.840.113549.2.13': 'sha512_256',
}
class HmacAlgorithm(Sequence):
_fields = [
('algorithm', HmacAlgorithmId),
('parameters', Any, {'optional': True}),
]
class DigestAlgorithmId(ObjectIdentifier):
_map = {
'1.2.840.113549.2.2': 'md2',
'1.2.840.113549.2.5': 'md5',
'1.3.14.3.2.26': 'sha1',
'2.16.840.1.101.3.4.2.4': 'sha224',
'2.16.840.1.101.3.4.2.1': 'sha256',
'2.16.840.1.101.3.4.2.2': 'sha384',
'2.16.840.1.101.3.4.2.3': 'sha512',
'2.16.840.1.101.3.4.2.5': 'sha512_224',
'2.16.840.1.101.3.4.2.6': 'sha512_256',
}
class DigestAlgorithm(_ForceNullParameters, Sequence):
_fields = [
('algorithm', DigestAlgorithmId),
('parameters', Any, {'optional': True}),
]
# This structure is what is signed with a SignedDigestAlgorithm
class DigestInfo(Sequence):
_fields = [
('digest_algorithm', DigestAlgorithm),
('digest', OctetString),
]
class MaskGenAlgorithmId(ObjectIdentifier):
_map = {
'1.2.840.113549.1.1.8': 'mgf1',
}
class MaskGenAlgorithm(Sequence):
_fields = [
('algorithm', MaskGenAlgorithmId),
('parameters', Any, {'optional': True}),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {
'mgf1': DigestAlgorithm
}
class TrailerField(Integer):
_map = {
1: 'trailer_field_bc',
}
class RSASSAPSSParams(Sequence):
_fields = [
(
'hash_algorithm',
DigestAlgorithm,
{
'explicit': 0,
'default': {'algorithm': 'sha1'},
}
),
(
'mask_gen_algorithm',
MaskGenAlgorithm,
{
'explicit': 1,
'default': {
'algorithm': 'mgf1',
'parameters': {'algorithm': 'sha1'},
},
}
),
(
'salt_length',
Integer,
{
'explicit': 2,
'default': 20,
}
),
(
'trailer_field',
TrailerField,
{
'explicit': 3,
'default': 'trailer_field_bc',
}
),
]
class SignedDigestAlgorithmId(ObjectIdentifier):
_map = {
'1.3.14.3.2.3': 'md5_rsa',
'1.3.14.3.2.29': 'sha1_rsa',
'1.3.14.7.2.3.1': 'md2_rsa',
'1.2.840.113549.1.1.2': 'md2_rsa',
'1.2.840.113549.1.1.4': 'md5_rsa',
'1.2.840.113549.1.1.5': 'sha1_rsa',
'1.2.840.113549.1.1.14': 'sha224_rsa',
'1.2.840.113549.1.1.11': 'sha256_rsa',
'1.2.840.113549.1.1.12': 'sha384_rsa',
'1.2.840.113549.1.1.13': 'sha512_rsa',
'1.2.840.113549.1.1.10': 'rsassa_pss',
'1.2.840.10040.4.3': 'sha1_dsa',
'1.3.14.3.2.13': 'sha1_dsa',
'1.3.14.3.2.27': 'sha1_dsa',
'2.16.840.1.101.3.4.3.1': 'sha224_dsa',
'2.16.840.1.101.3.4.3.2': 'sha256_dsa',
'1.2.840.10045.4.1': 'sha1_ecdsa',
'1.2.840.10045.4.3.1': 'sha224_ecdsa',
'1.2.840.10045.4.3.2': 'sha256_ecdsa',
'1.2.840.10045.4.3.3': 'sha384_ecdsa',
'1.2.840.10045.4.3.4': 'sha512_ecdsa',
# For when the digest is specified elsewhere in a Sequence
'1.2.840.113549.1.1.1': 'rsassa_pkcs1v15',
'1.2.840.10040.4.1': 'dsa',
'1.2.840.10045.4': 'ecdsa',
}
_reverse_map = {
'dsa': '1.2.840.10040.4.1',
'ecdsa': '1.2.840.10045.4',
'md2_rsa': '1.2.840.113549.1.1.2',
'md5_rsa': '1.2.840.113549.1.1.4',
'rsassa_pkcs1v15': '1.2.840.113549.1.1.1',
'rsassa_pss': '1.2.840.113549.1.1.10',
'sha1_dsa': '1.2.840.10040.4.3',
'sha1_ecdsa': '1.2.840.10045.4.1',
'sha1_rsa': '1.2.840.113549.1.1.5',
'sha224_dsa': '2.16.840.1.101.3.4.3.1',
'sha224_ecdsa': '1.2.840.10045.4.3.1',
'sha224_rsa': '1.2.840.113549.1.1.14',
'sha256_dsa': '2.16.840.1.101.3.4.3.2',
'sha256_ecdsa': '1.2.840.10045.4.3.2',
'sha256_rsa': '1.2.840.113549.1.1.11',
'sha384_ecdsa': '1.2.840.10045.4.3.3',
'sha384_rsa': '1.2.840.113549.1.1.12',
'sha512_ecdsa': '1.2.840.10045.4.3.4',
'sha512_rsa': '1.2.840.113549.1.1.13',
}
class SignedDigestAlgorithm(_ForceNullParameters, Sequence):
_fields = [
('algorithm', SignedDigestAlgorithmId),
('parameters', Any, {'optional': True}),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {
'rsassa_pss': RSASSAPSSParams,
}
@property
def signature_algo(self):
"""
:return:
A unicode string of "rsassa_pkcs1v15", "rsassa_pss", "dsa" or
"ecdsa"
"""
algorithm = self['algorithm'].native
algo_map = {
'md2_rsa': 'rsassa_pkcs1v15',
'md5_rsa': 'rsassa_pkcs1v15',
'sha1_rsa': 'rsassa_pkcs1v15',
'sha224_rsa': 'rsassa_pkcs1v15',
'sha256_rsa': 'rsassa_pkcs1v15',
'sha384_rsa': 'rsassa_pkcs1v15',
'sha512_rsa': 'rsassa_pkcs1v15',
'rsassa_pkcs1v15': 'rsassa_pkcs1v15',
'rsassa_pss': 'rsassa_pss',
'sha1_dsa': 'dsa',
'sha224_dsa': 'dsa',
'sha256_dsa': 'dsa',
'dsa': 'dsa',
'sha1_ecdsa': 'ecdsa',
'sha224_ecdsa': 'ecdsa',
'sha256_ecdsa': 'ecdsa',
'sha384_ecdsa': 'ecdsa',
'sha512_ecdsa': 'ecdsa',
'ecdsa': 'ecdsa',
}
if algorithm in algo_map:
return algo_map[algorithm]
raise ValueError(unwrap(
'''
Signature algorithm not known for %s
''',
algorithm
))
@property
def hash_algo(self):
"""
:return:
A unicode string of "md2", "md5", "sha1", "sha224", "sha256",
"sha384", "sha512", "sha512_224", "sha512_256"
"""
algorithm = self['algorithm'].native
algo_map = {
'md2_rsa': 'md2',
'md5_rsa': 'md5',
'sha1_rsa': 'sha1',
'sha224_rsa': 'sha224',
'sha256_rsa': 'sha256',
'sha384_rsa': 'sha384',
'sha512_rsa': 'sha512',
'sha1_dsa': 'sha1',
'sha224_dsa': 'sha224',
'sha256_dsa': 'sha256',
'sha1_ecdsa': 'sha1',
'sha224_ecdsa': 'sha224',
'sha256_ecdsa': 'sha256',
'sha384_ecdsa': 'sha384',
'sha512_ecdsa': 'sha512',
}
if algorithm in algo_map:
return algo_map[algorithm]
if algorithm == 'rsassa_pss':
return self['parameters']['hash_algorithm']['algorithm'].native
raise ValueError(unwrap(
'''
Hash algorithm not known for %s
''',
algorithm
))
class Pbkdf2Salt(Choice):
_alternatives = [
('specified', OctetString),
('other_source', AlgorithmIdentifier),
]
class Pbkdf2Params(Sequence):
_fields = [
('salt', Pbkdf2Salt),
('iteration_count', Integer),
('key_length', Integer, {'optional': True}),
('prf', HmacAlgorithm, {'default': {'algorithm': 'sha1'}}),
]
class KdfAlgorithmId(ObjectIdentifier):
_map = {
'1.2.840.113549.1.5.12': 'pbkdf2'
}
class KdfAlgorithm(Sequence):
_fields = [
('algorithm', KdfAlgorithmId),
('parameters', Any, {'optional': True}),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {
'pbkdf2': Pbkdf2Params
}
class DHParameters(Sequence):
"""
Original Name: DHParameter
Source: ftp://ftp.rsasecurity.com/pub/pkcs/ascii/pkcs-3.asc section 9
"""
_fields = [
('p', Integer),
('g', Integer),
('private_value_length', Integer, {'optional': True}),
]
class KeyExchangeAlgorithmId(ObjectIdentifier):
_map = {
'1.2.840.113549.1.3.1': 'dh',
}
class KeyExchangeAlgorithm(Sequence):
_fields = [
('algorithm', KeyExchangeAlgorithmId),
('parameters', Any, {'optional': True}),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {
'dh': DHParameters,
}
class Rc2Params(Sequence):
_fields = [
('rc2_parameter_version', Integer, {'optional': True}),
('iv', OctetString),
]
class Rc5ParamVersion(Integer):
_map = {
16: 'v1-0'
}
class Rc5Params(Sequence):
_fields = [
('version', Rc5ParamVersion),
('rounds', Integer),
('block_size_in_bits', Integer),
('iv', OctetString, {'optional': True}),
]
class Pbes1Params(Sequence):
_fields = [
('salt', OctetString),
('iterations', Integer),
]
class PSourceAlgorithmId(ObjectIdentifier):
_map = {
'1.2.840.113549.1.1.9': 'p_specified',
}
class PSourceAlgorithm(Sequence):
_fields = [
('algorithm', PSourceAlgorithmId),
('parameters', Any, {'optional': True}),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {
'p_specified': OctetString
}
class RSAESOAEPParams(Sequence):
_fields = [
(
'hash_algorithm',
DigestAlgorithm,
{
'explicit': 0,
'default': {'algorithm': 'sha1'}
}
),
(
'mask_gen_algorithm',
MaskGenAlgorithm,
{
'explicit': 1,
'default': {
'algorithm': 'mgf1',
'parameters': {'algorithm': 'sha1'}
}
}
),
(
'p_source_algorithm',
PSourceAlgorithm,
{
'explicit': 2,
'default': {
'algorithm': 'p_specified',
'parameters': b''
}
}
),
]
class DSASignature(Sequence):
"""
An ASN.1 class for translating between the OS crypto library's
representation of an (EC)DSA signature and the ASN.1 structure that is part
of various RFCs.
Original Name: DSS-Sig-Value
Source: https://tools.ietf.org/html/rfc3279#section-2.2.2
"""
_fields = [
('r', Integer),
('s', Integer),
]
@classmethod
def from_p1363(cls, data):
"""
Reads a signature from a byte string encoding accordint to IEEE P1363,
which is used by Microsoft's BCryptSignHash() function.
:param data:
A byte string from BCryptSignHash()
:return:
A DSASignature object
"""
r = int_from_bytes(data[0:len(data) // 2])
s = int_from_bytes(data[len(data) // 2:])
return cls({'r': r, 's': s})
def to_p1363(self):
"""
Dumps a signature to a byte string compatible with Microsoft's
BCryptVerifySignature() function.
:return:
A byte string compatible with BCryptVerifySignature()
"""
r_bytes = int_to_bytes(self['r'].native)
s_bytes = int_to_bytes(self['s'].native)
int_byte_length = max(len(r_bytes), len(s_bytes))
r_bytes = fill_width(r_bytes, int_byte_length)
s_bytes = fill_width(s_bytes, int_byte_length)
return r_bytes + s_bytes
class EncryptionAlgorithmId(ObjectIdentifier):
_map = {
'1.3.14.3.2.7': 'des',
'1.2.840.113549.3.7': 'tripledes_3key',
'1.2.840.113549.3.2': 'rc2',
'1.2.840.113549.3.9': 'rc5',
# From http://csrc.nist.gov/groups/ST/crypto_apps_infra/csor/algorithms.html#AES
'2.16.840.1.101.3.4.1.1': 'aes128_ecb',
'2.16.840.1.101.3.4.1.2': 'aes128_cbc',
'2.16.840.1.101.3.4.1.3': 'aes128_ofb',
'2.16.840.1.101.3.4.1.4': 'aes128_cfb',
'2.16.840.1.101.3.4.1.5': 'aes128_wrap',
'2.16.840.1.101.3.4.1.6': 'aes128_gcm',
'2.16.840.1.101.3.4.1.7': 'aes128_ccm',
'2.16.840.1.101.3.4.1.8': 'aes128_wrap_pad',
'2.16.840.1.101.3.4.1.21': 'aes192_ecb',
'2.16.840.1.101.3.4.1.22': 'aes192_cbc',
'2.16.840.1.101.3.4.1.23': 'aes192_ofb',
'2.16.840.1.101.3.4.1.24': 'aes192_cfb',
'2.16.840.1.101.3.4.1.25': 'aes192_wrap',
'2.16.840.1.101.3.4.1.26': 'aes192_gcm',
'2.16.840.1.101.3.4.1.27': 'aes192_ccm',
'2.16.840.1.101.3.4.1.28': 'aes192_wrap_pad',
'2.16.840.1.101.3.4.1.41': 'aes256_ecb',
'2.16.840.1.101.3.4.1.42': 'aes256_cbc',
'2.16.840.1.101.3.4.1.43': 'aes256_ofb',
'2.16.840.1.101.3.4.1.44': 'aes256_cfb',
'2.16.840.1.101.3.4.1.45': 'aes256_wrap',
'2.16.840.1.101.3.4.1.46': 'aes256_gcm',
'2.16.840.1.101.3.4.1.47': 'aes256_ccm',
'2.16.840.1.101.3.4.1.48': 'aes256_wrap_pad',
# From PKCS#5
'1.2.840.113549.1.5.13': 'pbes2',
'1.2.840.113549.1.5.1': 'pbes1_md2_des',
'1.2.840.113549.1.5.3': 'pbes1_md5_des',
'1.2.840.113549.1.5.4': 'pbes1_md2_rc2',
'1.2.840.113549.1.5.6': 'pbes1_md5_rc2',
'1.2.840.113549.1.5.10': 'pbes1_sha1_des',
'1.2.840.113549.1.5.11': 'pbes1_sha1_rc2',
# From PKCS#12
'1.2.840.113549.1.12.1.1': 'pkcs12_sha1_rc4_128',
'1.2.840.113549.1.12.1.2': 'pkcs12_sha1_rc4_40',
'1.2.840.113549.1.12.1.3': 'pkcs12_sha1_tripledes_3key',
'1.2.840.113549.1.12.1.4': 'pkcs12_sha1_tripledes_2key',
'1.2.840.113549.1.12.1.5': 'pkcs12_sha1_rc2_128',
'1.2.840.113549.1.12.1.6': 'pkcs12_sha1_rc2_40',
# PKCS#1 v2.2
'1.2.840.113549.1.1.1': 'rsaes_pkcs1v15',
'1.2.840.113549.1.1.7': 'rsaes_oaep',
}
class EncryptionAlgorithm(_ForceNullParameters, Sequence):
_fields = [
('algorithm', EncryptionAlgorithmId),
('parameters', Any, {'optional': True}),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {
'des': OctetString,
'tripledes_3key': OctetString,
'rc2': Rc2Params,
'rc5': Rc5Params,
'aes128_cbc': OctetString,
'aes192_cbc': OctetString,
'aes256_cbc': OctetString,
'aes128_ofb': OctetString,
'aes192_ofb': OctetString,
'aes256_ofb': OctetString,
# From PKCS#5
'pbes1_md2_des': Pbes1Params,
'pbes1_md5_des': Pbes1Params,
'pbes1_md2_rc2': Pbes1Params,
'pbes1_md5_rc2': Pbes1Params,
'pbes1_sha1_des': Pbes1Params,
'pbes1_sha1_rc2': Pbes1Params,
# From PKCS#12
'pkcs12_sha1_rc4_128': Pbes1Params,
'pkcs12_sha1_rc4_40': Pbes1Params,
'pkcs12_sha1_tripledes_3key': Pbes1Params,
'pkcs12_sha1_tripledes_2key': Pbes1Params,
'pkcs12_sha1_rc2_128': Pbes1Params,
'pkcs12_sha1_rc2_40': Pbes1Params,
# PKCS#1 v2.2
'rsaes_oaep': RSAESOAEPParams,
}
@property
def kdf(self):
"""
Returns the name of the key derivation function to use.
:return:
A unicode from of one of the following: "pbkdf1", "pbkdf2",
"pkcs12_kdf"
"""
encryption_algo = self['algorithm'].native
if encryption_algo == 'pbes2':
return self['parameters']['key_derivation_func']['algorithm'].native
if encryption_algo.find('.') == -1:
if encryption_algo.find('_') != -1:
encryption_algo, _ = encryption_algo.split('_', 1)
if encryption_algo == 'pbes1':
return 'pbkdf1'
if encryption_algo == 'pkcs12':
return 'pkcs12_kdf'
raise ValueError(unwrap(
'''
Encryption algorithm "%s" does not have a registered key
derivation function
''',
encryption_algo
))
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s", can not determine key
derivation function
''',
encryption_algo
))
@property
def kdf_hmac(self):
"""
Returns the HMAC algorithm to use with the KDF.
:return:
A unicode string of one of the following: "md2", "md5", "sha1",
"sha224", "sha256", "sha384", "sha512"
"""
encryption_algo = self['algorithm'].native
if encryption_algo == 'pbes2':
return self['parameters']['key_derivation_func']['parameters']['prf']['algorithm'].native
if encryption_algo.find('.') == -1:
if encryption_algo.find('_') != -1:
_, hmac_algo, _ = encryption_algo.split('_', 2)
return hmac_algo
raise ValueError(unwrap(
'''
Encryption algorithm "%s" does not have a registered key
derivation function
''',
encryption_algo
))
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s", can not determine key
derivation hmac algorithm
''',
encryption_algo
))
@property
def kdf_salt(self):
"""
Returns the byte string to use as the salt for the KDF.
:return:
A byte string
"""
encryption_algo = self['algorithm'].native
if encryption_algo == 'pbes2':
salt = self['parameters']['key_derivation_func']['parameters']['salt']
if salt.name == 'other_source':
raise ValueError(unwrap(
'''
Can not determine key derivation salt - the
reserved-for-future-use other source salt choice was
specified in the PBKDF2 params structure
'''
))
return salt.native
if encryption_algo.find('.') == -1:
if encryption_algo.find('_') != -1:
return self['parameters']['salt'].native
raise ValueError(unwrap(
'''
Encryption algorithm "%s" does not have a registered key
derivation function
''',
encryption_algo
))
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s", can not determine key
derivation salt
''',
encryption_algo
))
@property
def kdf_iterations(self):
"""
Returns the number of iterations that should be run via the KDF.
:return:
An integer
"""
encryption_algo = self['algorithm'].native
if encryption_algo == 'pbes2':
return self['parameters']['key_derivation_func']['parameters']['iteration_count'].native
if encryption_algo.find('.') == -1:
if encryption_algo.find('_') != -1:
return self['parameters']['iterations'].native
raise ValueError(unwrap(
'''
Encryption algorithm "%s" does not have a registered key
derivation function
''',
encryption_algo
))
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s", can not determine key
derivation iterations
''',
encryption_algo
))
@property
def key_length(self):
"""
Returns the key length to pass to the cipher/kdf. The PKCS#5 spec does
not specify a way to store the RC5 key length, however this tends not
to be a problem since OpenSSL does not support RC5 in PKCS#8 and OS X
does not provide an RC5 cipher for use in the Security Transforms
library.
:raises:
ValueError - when the key length can not be determined
:return:
An integer representing the length in bytes
"""
encryption_algo = self['algorithm'].native
if encryption_algo[0:3] == 'aes':
return {
'aes128_': 16,
'aes192_': 24,
'aes256_': 32,
}[encryption_algo[0:7]]
cipher_lengths = {
'des': 8,
'tripledes_3key': 24,
}
if encryption_algo in cipher_lengths:
return cipher_lengths[encryption_algo]
if encryption_algo == 'rc2':
rc2_params = self['parameters'].parsed['encryption_scheme']['parameters'].parsed
rc2_parameter_version = rc2_params['rc2_parameter_version'].native
# See page 24 of
# http://www.emc.com/collateral/white-papers/h11302-pkcs5v2-1-password-based-cryptography-standard-wp.pdf
encoded_key_bits_map = {
160: 5, # 40-bit
120: 8, # 64-bit
58: 16, # 128-bit
}
if rc2_parameter_version in encoded_key_bits_map:
return encoded_key_bits_map[rc2_parameter_version]
if rc2_parameter_version >= 256:
return rc2_parameter_version
if rc2_parameter_version is None:
return 4 # 32-bit default
raise ValueError(unwrap(
'''
Invalid RC2 parameter version found in EncryptionAlgorithm
parameters
'''
))
if encryption_algo == 'pbes2':
key_length = self['parameters']['key_derivation_func']['parameters']['key_length'].native
if key_length is not None:
return key_length
# If the KDF params don't specify the key size, we can infer it from
# the encryption scheme for all schemes except for RC5. However, in
# practical terms, neither OpenSSL or OS X support RC5 for PKCS#8
# so it is unlikely to be an issue that is run into.
return self['parameters']['encryption_scheme'].key_length
if encryption_algo.find('.') == -1:
return {
'pbes1_md2_des': 8,
'pbes1_md5_des': 8,
'pbes1_md2_rc2': 8,
'pbes1_md5_rc2': 8,
'pbes1_sha1_des': 8,
'pbes1_sha1_rc2': 8,
'pkcs12_sha1_rc4_128': 16,
'pkcs12_sha1_rc4_40': 5,
'pkcs12_sha1_tripledes_3key': 24,
'pkcs12_sha1_tripledes_2key': 16,
'pkcs12_sha1_rc2_128': 16,
'pkcs12_sha1_rc2_40': 5,
}[encryption_algo]
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s"
''',
encryption_algo
))
@property
def encryption_mode(self):
"""
Returns the name of the encryption mode to use.
:return:
A unicode string from one of the following: "cbc", "ecb", "ofb",
"cfb", "wrap", "gcm", "ccm", "wrap_pad"
"""
encryption_algo = self['algorithm'].native
if encryption_algo[0:7] in set(['aes128_', 'aes192_', 'aes256_']):
return encryption_algo[7:]
if encryption_algo[0:6] == 'pbes1_':
return 'cbc'
if encryption_algo[0:7] == 'pkcs12_':
return 'cbc'
if encryption_algo in set(['des', 'tripledes_3key', 'rc2', 'rc5']):
return 'cbc'
if encryption_algo == 'pbes2':
return self['parameters']['encryption_scheme'].encryption_mode
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s"
''',
encryption_algo
))
@property
def encryption_cipher(self):
"""
Returns the name of the symmetric encryption cipher to use. The key
length can be retrieved via the .key_length property to disabiguate
between different variations of TripleDES, AES, and the RC* ciphers.
:return:
A unicode string from one of the following: "rc2", "rc5", "des",
"tripledes", "aes"
"""
encryption_algo = self['algorithm'].native
if encryption_algo[0:7] in set(['aes128_', 'aes192_', 'aes256_']):
return 'aes'
if encryption_algo in set(['des', 'rc2', 'rc5']):
return encryption_algo
if encryption_algo == 'tripledes_3key':
return 'tripledes'
if encryption_algo == 'pbes2':
return self['parameters']['encryption_scheme'].encryption_cipher
if encryption_algo.find('.') == -1:
return {
'pbes1_md2_des': 'des',
'pbes1_md5_des': 'des',
'pbes1_md2_rc2': 'rc2',
'pbes1_md5_rc2': 'rc2',
'pbes1_sha1_des': 'des',
'pbes1_sha1_rc2': 'rc2',
'pkcs12_sha1_rc4_128': 'rc4',
'pkcs12_sha1_rc4_40': 'rc4',
'pkcs12_sha1_tripledes_3key': 'tripledes',
'pkcs12_sha1_tripledes_2key': 'tripledes',
'pkcs12_sha1_rc2_128': 'rc2',
'pkcs12_sha1_rc2_40': 'rc2',
}[encryption_algo]
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s"
''',
encryption_algo
))
@property
def encryption_block_size(self):
"""
Returns the block size of the encryption cipher, in bytes.
:return:
An integer that is the block size in bytes
"""
encryption_algo = self['algorithm'].native
if encryption_algo[0:7] in set(['aes128_', 'aes192_', 'aes256_']):
return 16
cipher_map = {
'des': 8,
'tripledes_3key': 8,
'rc2': 8,
}
if encryption_algo in cipher_map:
return cipher_map[encryption_algo]
if encryption_algo == 'rc5':
return self['parameters'].parsed['block_size_in_bits'].native / 8
if encryption_algo == 'pbes2':
return self['parameters']['encryption_scheme'].encryption_block_size
if encryption_algo.find('.') == -1:
return {
'pbes1_md2_des': 8,
'pbes1_md5_des': 8,
'pbes1_md2_rc2': 8,
'pbes1_md5_rc2': 8,
'pbes1_sha1_des': 8,
'pbes1_sha1_rc2': 8,
'pkcs12_sha1_rc4_128': 0,
'pkcs12_sha1_rc4_40': 0,
'pkcs12_sha1_tripledes_3key': 8,
'pkcs12_sha1_tripledes_2key': 8,
'pkcs12_sha1_rc2_128': 8,
'pkcs12_sha1_rc2_40': 8,
}[encryption_algo]
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s"
''',
encryption_algo
))
@property
def encryption_iv(self):
"""
Returns the byte string of the initialization vector for the encryption
scheme. Only the PBES2 stores the IV in the params. For PBES1, the IV
is derived from the KDF and this property will return None.
:return:
A byte string or None
"""
encryption_algo = self['algorithm'].native
if encryption_algo in set(['rc2', 'rc5']):
return self['parameters'].parsed['iv'].native
# For DES/Triple DES and AES the IV is the entirety of the parameters
octet_string_iv_oids = set([
'des',
'tripledes_3key',
'aes128_cbc',
'aes192_cbc',
'aes256_cbc',
'aes128_ofb',
'aes192_ofb',
'aes256_ofb',
])
if encryption_algo in octet_string_iv_oids:
return self['parameters'].native
if encryption_algo == 'pbes2':
return self['parameters']['encryption_scheme'].encryption_iv
# All of the PBES1 algos use their KDF to create the IV. For the pbkdf1,
# the KDF is told to generate a key that is an extra 8 bytes long, and
# that is used for the IV. For the PKCS#12 KDF, it is called with an id
# of 2 to generate the IV. In either case, we can't return the IV
# without knowing the user's password.
if encryption_algo.find('.') == -1:
return None
raise ValueError(unwrap(
'''
Unrecognized encryption algorithm "%s"
''',
encryption_algo
))
class Pbes2Params(Sequence):
_fields = [
('key_derivation_func', KdfAlgorithm),
('encryption_scheme', EncryptionAlgorithm),
]
class Pbmac1Params(Sequence):
_fields = [
('key_derivation_func', KdfAlgorithm),
('message_auth_scheme', HmacAlgorithm),
]
class Pkcs5MacId(ObjectIdentifier):
_map = {
'1.2.840.113549.1.5.14': 'pbmac1',
}
class Pkcs5MacAlgorithm(Sequence):
_fields = [
('algorithm', Pkcs5MacId),
('parameters', Any),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {
'pbmac1': Pbmac1Params,
}
EncryptionAlgorithm._oid_specs['pbes2'] = Pbes2Params
class AnyAlgorithmId(ObjectIdentifier):
_map = {}
def _setup(self):
_map = self.__class__._map
for other_cls in (EncryptionAlgorithmId, SignedDigestAlgorithmId, DigestAlgorithmId):
for oid, name in other_cls._map.items():
_map[oid] = name
class AnyAlgorithmIdentifier(_ForceNullParameters, Sequence):
_fields = [
('algorithm', AnyAlgorithmId),
('parameters', Any, {'optional': True}),
]
_oid_pair = ('algorithm', 'parameters')
_oid_specs = {}
def _setup(self):
Sequence._setup(self)
specs = self.__class__._oid_specs
for other_cls in (EncryptionAlgorithm, SignedDigestAlgorithm):
for oid, spec in other_cls._oid_specs.items():
specs[oid] = spec
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