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# Copyright (C) 2015 JWCrypto Project Contributors - see LICENSE file
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives.asymmetric import ec
from jwcrypto.common import base64url_decode
import json
# draft-ietf-jose-json-web-algorithms-24 - 7.4
JWKTypesRegistry = {'EC': 'Elliptic Curve',
'RSA': 'RSA',
'oct': 'Octet sequence'}
# draft-ietf-jose-json-web-algorithms-24 - 7.5
# It is part of the JWK Parameters Registry, but we want a more
# specific map for internal usage
JWKValuesRegistry = {'EC': {'crv': ('Curve', 'Public'),
'x': ('X Coordinate', 'Public'),
'y': ('Y Coordinate', 'Public'),
'd': ('ECC Private Key', 'Private')},
'RSA': {'n': ('Modulus', 'Public'),
'e': ('Exponent', 'Public'),
'd': ('Private Exponent', 'Private'),
'p': ('First Prime Factor', 'Private'),
'q': ('Second Prime Factor', 'Private'),
'dp': ('First Factor CRT Exponent', 'Private'),
'dq': ('Second Factor CRT Exponent', 'Private'),
'qi': ('First CRT Coefficient', 'Private')},
'oct': {'k': ('Key Value', 'Private')}}
JWKParamsRegistry = {'kty': ('Key Type', 'Public', ),
'use': ('Public Key Use', 'Public'),
'key_ops': ('Key Operations', 'Public'),
'alg': ('Algorithm', 'Public'),
'kid': ('Key ID', 'Public'),
'x5u': ('X.509 URL', 'Public'),
'x5c': ('X.509 Certificate Chain', 'Public'),
'x5t': ('X.509 Certificate SHA-1 Thumbprint', 'Public'),
'x5t#S256': ('X.509 Certificate SHA-256 Thumbprint',
'Public')}
# draft-ietf-jose-json-web-algorithms-24 - 7.6
JWKEllipticCurveRegistry = {'P-256': 'P-256 curve',
'P-384': 'P-384 curve',
'P-521': 'P-521 curve'}
# draft-ietf-jose-json-web-key-41 - 8.2
JWKUseRegistry = {'sig': 'Digital Signature or MAC',
'enc': 'Encryption'}
# draft-ietf-jose-json-web-key-41 - 8.2
JWKOperationsRegistry = {'sign': 'Compute digital Signature or MAC',
'verify': 'Verify digital signature or MAC',
'encrypt': 'Encrypt content',
'decrypt': 'Decrypt content and validate'
' decryption, if applicable',
'wrapKey': 'Encrypt key',
'unwrapKey': 'Decrypt key and validate'
' decryption, if applicable',
'deriveKey': 'Derive key',
'deriveBits': 'Derive bits not to be used as a key'}
class InvalidJWKType(Exception):
def __init__(self, value=None):
super(InvalidJWKType, self).__init__()
self.value = value
def __str__(self):
return 'Unknown type "%s", valid types are: %s' % (
self.value, JWKTypesRegistry.keys())
class InvalidJWKUsage(Exception):
def __init__(self, use, value):
super(InvalidJWKUsage, self).__init__()
self.value = value
self.use = use
def __str__(self):
if self.use in JWKUseRegistry.keys():
usage = JWKUseRegistry[self.use]
else:
usage = 'Unknown(%s)' % self.use
if self.value in JWKUseRegistry.keys():
valid = JWKUseRegistry[self.value]
else:
valid = 'Unknown(%s)' % self.value
return 'Invalid usage requested: "%s". Valid for: "%s"' % (usage,
valid)
class InvalidJWKOperation(Exception):
def __init__(self, operation, values):
super(InvalidJWKOperation, self).__init__()
self.op = operation
self.values = values
def __str__(self):
if self.op in JWKOperationsRegistry.keys():
op = JWKOperationsRegistry[self.op]
else:
op = 'Unknown(%s)' % self.op
valid = list()
for v in self.values:
if v in JWKOperationsRegistry.keys():
valid.append(JWKOperationsRegistry[v])
else:
valid.append('Unknown(%s)' % v)
return 'Invalid operation requested: "%s". Valid for: "%s"' % (op,
valid)
class InvalidJWKValue(Exception):
pass
class JWK(object):
def __init__(self, **kwargs):
names = kwargs.keys()
self._params = dict()
for name in JWKParamsRegistry.keys():
if name in kwargs:
self._params[name] = kwargs[name]
while name in names:
names.remove(name)
kty = self._params.get('kty', None)
if kty not in JWKTypesRegistry:
raise InvalidJWKType(kty)
self._key = dict()
for name in JWKValuesRegistry[kty].keys():
if name in kwargs:
self._key[name] = kwargs[name]
while name in names:
names.remove(name)
if len(names) != 0:
raise InvalidJWKValue('Unknown key parameters: %s' % names)
if len(self._key) == 0:
raise InvalidJWKValue('No Key Values found')
def export(self):
d = dict()
d.update(self._params)
d.update(self._key)
return json.dumps(d)
@property
def key_type(self):
return self._params.get('kty', None)
@property
def key_id(self):
return self._params.get('kid', None)
def get_curve(self, arg):
k = self._key
if self._params['kty'] != 'EC':
raise InvalidJWKType('Not an EC key')
if arg and k['crv'] != arg:
raise InvalidJWKValue('Curve requested is "%s", but '
'key curve is "%s"' % (arg, k['crv']))
if k['crv'] == 'P-256':
return ec.SECP256R1()
elif k['crv'] == 'P-384':
return ec.SECP384R1()
elif k['crv'] == 'P-521':
return ec.SECP521R1()
else:
raise InvalidJWKValue('Unknown Elliptic Curve Type')
def _check_constraints(self, usage, operation):
use = self._params.get('use', None)
if use and use != usage:
raise InvalidJWKUsage(usage, use)
ops = self._params.get('key_ops', None)
if ops:
if not isinstance(ops, list):
ops = [ops]
if operation not in ops:
raise InvalidJWKOperation(operation, ops)
# TODO: check alg ?
def _decode_int(self, n):
return int(base64url_decode(n).encode('hex'), 16)
def _rsa_pub(self, k):
return rsa.RSAPublicNumbers(self._decode_int(k['e']),
self._decode_int(k['n']))
def _rsa_pri(self, k):
return rsa.RSAPrivateNumbers(self._decode_int(k['p']),
self._decode_int(k['q']),
self._decode_int(k['d']),
self._decode_int(k['dp']),
self._decode_int(k['dq']),
self._decode_int(k['qi']),
self._rsa_pub(k))
def _ec_pub(self, k, curve):
return ec.EllipticCurvePublicNumbers(self._decode_int(k['x']),
self._decode_int(k['y']),
self.get_curve(curve))
def _ec_pri(self, k, curve):
return ec.EllipticCurvePrivateNumbers(self._decode_int(k['d']),
self._ec_pub(k, curve))
def sign_key(self, arg=None):
self._check_constraints('sig', 'sign')
if self._params['kty'] == 'oct':
return self._key['k']
elif self._params['kty'] == 'RSA':
return self._rsa_pri(self._key).private_key(default_backend())
elif self._params['kty'] == 'EC':
return self._ec_pri(self._key, arg).private_key(default_backend())
else:
raise NotImplementedError
def verify_key(self, arg=None):
self._check_constraints('sig', 'verify')
if self._params['kty'] == 'oct':
return self._key['k']
elif self._params['kty'] == 'RSA':
return self._rsa_pub(self._key).public_key(default_backend())
elif self._params['kty'] == 'EC':
return self._ec_pub(self._key, arg).public_key(default_backend())
else:
raise NotImplementedError
def encrypt_key(self, arg=None):
self._check_constraints('enc', 'encrypt')
if self._params['kty'] == 'oct':
return self._key['k']
elif self._params['kty'] == 'RSA':
return self._rsa_pub(self._key).public_key(default_backend())
elif self._params['kty'] == 'EC':
return self._ec_pub(self._key, arg).public_key(default_backend())
else:
raise NotImplementedError
def decrypt_key(self, arg=None):
self._check_constraints('enc', 'decrypt')
if self._params['kty'] == 'oct':
return self._key['k']
elif self._params['kty'] == 'RSA':
return self._rsa_pri(self._key).private_key(default_backend())
elif self._params['kty'] == 'EC':
return self._ec_pri(self._key, arg).private_key(default_backend())
else:
raise NotImplementedError
class JWKSet(set):
def add(self, elem):
if not isinstance(elem, JWK):
raise TypeError('Only JWK objects are valid elements')
set.add(self, elem)
def export(self):
keys = list()
for jwk in self:
keys.append(json.loads(jwk.export()))
return json.dumps({'keys': keys})
def get_key(self, kid):
for jwk in self:
if jwk.key_id == kid:
return jwk
return None
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