# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
import abc
import six
from cryptography import utils
@six.add_metaclass(abc.ABCMeta)
class EllipticCurve(object):
@abc.abstractproperty
def name(self):
"""
The name of the curve. e.g. secp256r1.
"""
@abc.abstractproperty
def key_size(self):
"""
Bit size of a secret scalar for the curve.
"""
@six.add_metaclass(abc.ABCMeta)
class EllipticCurveSignatureAlgorithm(object):
@abc.abstractproperty
def algorithm(self):
"""
The digest algorithm used with this signature.
"""
@six.add_metaclass(abc.ABCMeta)
class EllipticCurvePrivateKey(object):
@abc.abstractmethod
def signer(self, signature_algorithm):
"""
Returns an AsymmetricSignatureContext used for signing data.
"""
@abc.abstractmethod
def exchange(self, algorithm, peer_public_key):
"""
Performs a key exchange operation using the provided algorithm with the
provided peer's public key.
"""
@abc.abstractmethod
def public_key(self):
"""
The EllipticCurvePublicKey for this private key.
"""
@abc.abstractproperty
def curve(self):
"""
The EllipticCurve that this key is on.
"""
@abc.abstractproperty
def key_size(self):
"""
Bit size of a secret scalar for the curve.
"""
@abc.abstractproperty
def sign(self, data, signature_algorithm):
"""
Signs the data
"""
@six.add_metaclass(abc.ABCMeta)
class EllipticCurvePrivateKeyWithSerialization(EllipticCurvePrivateKey):
@abc.abstractmethod
def private_numbers(self):
"""
Returns an EllipticCurvePrivateNumbers.
"""
@abc.abstractmethod
def private_bytes(self, encoding, format, encryption_algorithm):
"""
Returns the key serialized as bytes.
"""
@six.add_metaclass(abc.ABCMeta)
class EllipticCurvePublicKey(object):
@abc.abstractmethod
def verifier(self, signature, signature_algorithm):
"""
Returns an AsymmetricVerificationContext used for signing data.
"""
@abc.abstractproperty
def curve(self):
"""
The EllipticCurve that this key is on.
"""
@abc.abstractproperty
def key_size(self):
"""
Bit size of a secret scalar for the curve.
"""
@abc.abstractmethod
def public_numbers(self):
"""
Returns an EllipticCurvePublicNumbers.
"""
@abc.abstractmethod
def public_bytes(self, encoding, format):
"""
Returns the key serialized as bytes.
"""
@abc.abstractmethod
def verify(self, signature, data, signature_algorithm):
"""
Verifies the signature of the data.
"""
EllipticCurvePublicKeyWithSerialization = EllipticCurvePublicKey
@utils.register_interface(EllipticCurve)
class SECT571R1(object):
name = "sect571r1"
key_size = 571
@utils.register_interface(EllipticCurve)
class SECT409R1(object):
name = "sect409r1"
key_size = 409
@utils.register_interface(EllipticCurve)
class SECT283R1(object):
name = "sect283r1"
key_size = 283
@utils.register_interface(EllipticCurve)
class SECT233R1(object):
name = "sect233r1"
key_size = 233
@utils.register_interface(EllipticCurve)
class SECT163R2(object):
name = "sect163r2"
key_size = 163
@utils.register_interface(EllipticCurve)
class SECT571K1(object):
name = "sect571k1"
key_size = 571
@utils.register_interface(EllipticCurve)
class SECT409K1(object):
name = "sect409k1"
key_size = 409
@utils.register_interface(EllipticCurve)
class SECT283K1(object):
name = "sect283k1"
key_size = 283
@utils.register_interface(EllipticCurve)
class SECT233K1(object):
name = "sect233k1"
key_size = 233
@utils.register_interface(EllipticCurve)
class SECT163K1(object):
name = "sect163k1"
key_size = 163
@utils.register_interface(EllipticCurve)
class SECP521R1(object):
name = "secp521r1"
key_size = 521
@utils.register_interface(EllipticCurve)
class SECP384R1(object):
name = "secp384r1"
key_size = 384
@utils.register_interface(EllipticCurve)
class SECP256R1(object):
name = "secp256r1"
key_size = 256
@utils.register_interface(EllipticCurve)
class SECP256K1(object):
name = "secp256k1"
key_size = 256
@utils.register_interface(EllipticCurve)
class SECP224R1(object):
name = "secp224r1"
key_size = 224
@utils.register_interface(EllipticCurve)
class SECP192R1(object):
name = "secp192r1"
key_size = 192
_CURVE_TYPES = {
"prime192v1": SECP192R1,
"prime256v1": SECP256R1,
"secp192r1": SECP192R1,
"secp224r1": SECP224R1,
"secp256r1": SECP256R1,
"secp384r1": SECP384R1,
"secp521r1": SECP521R1,
"secp256k1": SECP256K1,
"sect163k1": SECT163K1,
"sect233k1": SECT233K1,
"sect283k1": SECT283K1,
"sect409k1": SECT409K1,
"sect571k1": SECT571K1,
"sect163r2": SECT163R2,
"sect233r1": SECT233R1,
"sect283r1": SECT283R1,
"sect409r1": SECT409R1,
"sect571r1": SECT571R1,
}
@utils.register_interface(EllipticCurveSignatureAlgorithm)
class ECDSA(object):
def __init__(self, algorithm):
self._algorithm = algorithm
algorithm = utils.read_only_property("_algorithm")
def generate_private_key(curve, backend):
return backend.generate_elliptic_curve_private_key(curve)
def derive_private_key(private_value, curve, backend):
if not isinstance(private_value, six.integer_types):
raise TypeError("private_value must be an integer type.")
if private_value <= 0:
raise ValueError("private_value must be a positive integer.")
if not isinstance(curve, EllipticCurve):
raise TypeError("curve must provide the EllipticCurve interface.")
return backend.derive_elliptic_curve_private_key(private_value, curve)
class EllipticCurvePublicNumbers(object):
def __init__(self, x, y, curve):
if (
not isinstance(x, six.integer_types) or
not isinstance(y, six.integer_types)
):
raise TypeError("x and y must be integers.")
if not isinstance(curve, EllipticCurve):
raise TypeError("curve must provide the EllipticCurve interface.")
self._y = y
self._x = x
self._curve = curve
def public_key(self, backend):
return backend.load_elliptic_curve_public_numbers(self)
def encode_point(self):
# key_size is in bits. Convert to bytes and round up
byte_length = (self.curve.key_size + 7) // 8
return (
b'\x04' + utils.int_to_bytes(self.x, byte_length) +
utils.int_to_bytes(self.y, byte_length)
)
@classmethod
def from_encoded_point(cls, curve, data):
if not isinstance(curve, EllipticCurve):
raise TypeError("curve must be an EllipticCurve instance")
if data.startswith(b'\x04'):
# key_size is in bits. Convert to bytes and round up
byte_length = (curve.key_size + 7) // 8
if len(data) == 2 * byte_length + 1:
x = utils.int_from_bytes(data[1:byte_length + 1], 'big')
y = utils.int_from_bytes(data[byte_length + 1:], 'big')
return cls(x, y, curve)
else:
raise ValueError('Invalid elliptic curve point data length')
else:
raise ValueError('Unsupported elliptic curve point type')
curve = utils.read_only_property("_curve")
x = utils.read_only_property("_x")
y = utils.read_only_property("_y")
def __eq__(self, other):
if not isinstance(other, EllipticCurvePublicNumbers):
return NotImplemented
return (
self.x == other.x and
self.y == other.y and
self.curve.name == other.curve.name and
self.curve.key_size == other.curve.key_size
)
def __ne__(self, other):
return not self == other
def __hash__(self):
return hash((self.x, self.y, self.curve.name, self.curve.key_size))
def __repr__(self):
return (
"<EllipticCurvePublicNumbers(curve={0.curve.name}, x={0.x}, "
"y={0.y}>".format(self)
)
class EllipticCurvePrivateNumbers(object):
def __init__(self, private_value, public_numbers):
if not isinstance(private_value, six.integer_types):
raise TypeError("private_value must be an integer.")
if not isinstance(public_numbers, EllipticCurvePublicNumbers):
raise TypeError(
"public_numbers must be an EllipticCurvePublicNumbers "
"instance."
)
self._private_value = private_value
self._public_numbers = public_numbers
def private_key(self, backend):
return backend.load_elliptic_curve_private_numbers(self)
private_value = utils.read_only_property("_private_value")
public_numbers = utils.read_only_property("_public_numbers")
def __eq__(self, other):
if not isinstance(other, EllipticCurvePrivateNumbers):
return NotImplemented
return (
self.private_value == other.private_value and
self.public_numbers == other.public_numbers
)
def __ne__(self, other):
return not self == other
def __hash__(self):
return hash((self.private_value, self.public_numbers))
class ECDH(object):
pass