Python cryptography.hazmat.primitives.asymmetric.ec.SECP256R1 Examples

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    numbers = ec.EllipticCurvePublicNumbers.from_encoded_point(curve, data)
    return numbers.public_key(backend) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    return ec.EllipticCurvePublicKey.from_encoded_point(curve, data) 

def generate_signature(self, pri_key: str, msg: bytes) -> str:
        if self.__scheme == SignatureScheme.SHA224withECDSA:
            private_key = ec.derive_private_key(int(pri_key, 16), ec.SECP224R1(), default_backend())
            signature = private_key.sign(
                msg,
                ec.ECDSA(hashes.SHA224())
            )
        elif self.__scheme == SignatureScheme.SHA256withECDSA:
            private_key = ec.derive_private_key(int(pri_key, 16), ec.SECP256R1(), default_backend())
            signature = private_key.sign(
                msg,
                ec.ECDSA(hashes.SHA256())
            )
        elif self.__scheme == SignatureScheme.SHA384withECDSA:
            private_key = ec.derive_private_key(int(pri_key, 16), ec.SECP384R1(), default_backend())
            signature = private_key.sign(
                msg,
                ec.ECDSA(hashes.SHA384())
            )
        else:
            raise SDKException(ErrorCode.other_error('Invalid signature scheme.'))
        sign = SignatureHandler.dsa_der_to_plain(signature)
        return sign 

def generate(cls, curve=ec.SECP256R1(), progress_func=None, bits=None):
        """
        Generate a new private ECDSA key.  This factory function can be used to
        generate a new host key or authentication key.

        :param function progress_func: Not used for this type of key.
        :returns: A new private key (`.ECDSAKey`) object
        """
        if bits is not None:
            curve = cls._ECDSA_CURVES.get_by_key_length(bits)
            if curve is None:
                raise ValueError("Unsupported key length: %d"%(bits))
            curve = curve.curve_class()

        private_key = ec.generate_private_key(curve, backend=default_backend())
        return ECDSAKey(vals=(private_key, private_key.public_key()))

    ###  internals... 

def test_fromPrivateBlobECDSA(self):
        """
        A private EC key is correctly generated from a private key blob.
        """
        from cryptography.hazmat.backends import default_backend
        from cryptography.hazmat.primitives.asymmetric import ec
        from cryptography.hazmat.primitives import serialization
        publicNumbers = ec.EllipticCurvePublicNumbers(
            x=keydata.ECDatanistp256['x'], y=keydata.ECDatanistp256['y'],
            curve=ec.SECP256R1())
        ecblob = (
            common.NS(keydata.ECDatanistp256['curve']) +
            common.NS(keydata.ECDatanistp256['curve'][-8:]) +
            common.NS(publicNumbers.public_key(default_backend()).public_bytes(
                serialization.Encoding.X962,
                serialization.PublicFormat.UncompressedPoint
            )) +
            common.MP(keydata.ECDatanistp256['privateValue'])
        )

        eckey = keys.Key._fromString_PRIVATE_BLOB(ecblob)

        self.assertFalse(eckey.isPublic())
        self.assertEqual(keydata.ECDatanistp256, eckey.data()) 

def _process_jwk(self, jwk_dict):
        if not jwk_dict.get('kty') == 'EC':
            raise JWKError("Incorrect key type. Expected: 'EC', Received: %s" % jwk_dict.get('kty'))

        if not all(k in jwk_dict for k in ['x', 'y', 'crv']):
            raise JWKError('Mandatory parameters are missing')

        x = base64_to_long(jwk_dict.get('x'))
        y = base64_to_long(jwk_dict.get('y'))
        curve = {
            'P-256': ec.SECP256R1,
            'P-384': ec.SECP384R1,
            'P-521': ec.SECP521R1,
        }[jwk_dict['crv']]

        public = ec.EllipticCurvePublicNumbers(x, y, curve())

        if 'd' in jwk_dict:
            d = base64_to_long(jwk_dict.get('d'))
            private = ec.EllipticCurvePrivateNumbers(d, public)

            return private.private_key(self.cryptography_backend())
        else:
            return public.public_key(self.cryptography_backend()) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    return ec.EllipticCurvePublicKey.from_encoded_point(curve, data) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    numbers = ec.EllipticCurvePublicNumbers.from_encoded_point(curve, data)
    return numbers.public_key(backend) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    numbers = ec.EllipticCurvePublicNumbers.from_encoded_point(curve, data)
    return numbers.public_key(backend) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    return ec.EllipticCurvePublicKey.from_encoded_point(curve, data) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    return ec.EllipticCurvePublicKey.from_encoded_point(curve, data) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _ssh_read_next_string(decoded_data)
    data, rest = _ssh_read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    return ec.EllipticCurvePublicKey.from_encoded_point(curve, data) 

def __init__(self, security_level=CURVE_P_256_Size, hash_algorithm=SHA2):
        """ Init curve and hash function.

        :param security_level: security level
        :param hash_algorithm: hash function
        :return: an instance of Ecies
        """
        if security_level == CURVE_P_256_Size:
            # order = openssl.backend._lib.BN_new()
            # curve = openssl.backend._lib.EC_GROUP_new_by_curve_name(
            #     openssl.backend._lib.NID_X9_62_prime256v1)
            # openssl.backend._lib.EC_GROUP_get_order(
            #     curve, order, openssl.backend._ffi.NULL)
            self.order = int("115792089210356248762697446949407573529"
                             "996955224135760342422259061068512044369")
            self.half_order = self.order >> 1
            self.curve = ec.SECP256R1
            self.sign_hash_algorithm = hashes.SHA256()
        else:
            # order = openssl.backend._lib.BN_new()
            # curve = openssl.backend._lib.EC_GROUP_new_by_curve_name(
            #     openssl.backend._lib.NID_secp384r1)
            # openssl.backend._lib.EC_GROUP_get_order(
            #     curve, order, openssl.backend._ffi.NULL)
            self.order = int("39402006196394479212279040100"
                             "14361380507973927046544666794"
                             "69052796276593991132635693989"
                             "56308152294913554433653942643")
            self.half_order = self.order >> 1
            self.curve = ec.SECP384R1
            self.sign_hash_algorithm = hashes.SHA384()

        if hash_algorithm == SHA2:
            self._hash = hashlib.sha256
        elif hash_algorithm == SHA3 and security_level == CURVE_P_256_Size:
            self._hash = hashlib.sha3_256
        else:
            self._hash = hashlib.sha3_384 

def _openssh_public_key_bytes(self, key):
        if isinstance(key, rsa.RSAPublicKey):
            public_numbers = key.public_numbers()
            return b"ssh-rsa " + base64.b64encode(
                serialization._ssh_write_string(b"ssh-rsa") +
                serialization._ssh_write_mpint(public_numbers.e) +
                serialization._ssh_write_mpint(public_numbers.n)
            )
        elif isinstance(key, dsa.DSAPublicKey):
            public_numbers = key.public_numbers()
            parameter_numbers = public_numbers.parameter_numbers
            return b"ssh-dss " + base64.b64encode(
                serialization._ssh_write_string(b"ssh-dss") +
                serialization._ssh_write_mpint(parameter_numbers.p) +
                serialization._ssh_write_mpint(parameter_numbers.q) +
                serialization._ssh_write_mpint(parameter_numbers.g) +
                serialization._ssh_write_mpint(public_numbers.y)
            )
        else:
            assert isinstance(key, ec.EllipticCurvePublicKey)
            public_numbers = key.public_numbers()
            try:
                curve_name = {
                    ec.SECP256R1: b"nistp256",
                    ec.SECP384R1: b"nistp384",
                    ec.SECP521R1: b"nistp521",
                }[type(public_numbers.curve)]
            except KeyError:
                raise ValueError(
                    "Only SECP256R1, SECP384R1, and SECP521R1 curves are "
                    "supported by the SSH public key format"
                )
            return b"ecdsa-sha2-" + curve_name + b" " + base64.b64encode(
                serialization._ssh_write_string(b"ecdsa-sha2-" + curve_name) +
                serialization._ssh_write_string(curve_name) +
                serialization._ssh_write_string(public_numbers.encode_point())
            ) 

def push_subscription_generate_keys(self):
        """
        Generates a private key, public key and shared secret for use in webpush subscriptions.
        
        Returns two dicts: One with the private key and shared secret and another with the 
        public key and shared secret.
        """
        if not IMPL_HAS_CRYPTO:
            raise NotImplementedError('To use the crypto tools, please install the webpush feature dependencies.')
        
        push_key_pair = ec.generate_private_key(ec.SECP256R1(), default_backend())
        push_key_priv = push_key_pair.private_numbers().private_value
        
        crypto_ver = cryptography.__version__
        if len(crypto_ver) < 5:
            crypto_ver += ".0"
        if bigger_version(crypto_ver, "2.5.0") == crypto_ver:
            push_key_pub = push_key_pair.public_key().public_bytes(serialization.Encoding.X962, serialization.PublicFormat.UncompressedPoint)
        else:
            push_key_pub = push_key_pair.public_key().public_numbers().encode_point() 
        push_shared_secret = os.urandom(16)
        
        priv_dict = {
            'privkey': push_key_priv,
            'auth': push_shared_secret
        }
        
        pub_dict = {
            'pubkey': push_key_pub,
            'auth': push_shared_secret
        }
        
        return priv_dict, pub_dict 

def push_subscription_decrypt_push(self, data, decrypt_params, encryption_header, crypto_key_header):
        """
        Decrypts `data` received in a webpush request. Requires the private key dict 
        from `push_subscription_generate_keys()`_ (`decrypt_params`) as well as the 
        Encryption and server Crypto-Key headers from the received webpush
        
        Returns the decoded webpush as a `push notification dict`_.
        """
        if (not IMPL_HAS_ECE) or (not IMPL_HAS_CRYPTO):
            raise NotImplementedError('To use the crypto tools, please install the webpush feature dependencies.')
        
        salt = self.__decode_webpush_b64(encryption_header.split("salt=")[1].strip())
        dhparams = self.__decode_webpush_b64(crypto_key_header.split("dh=")[1].split(";")[0].strip())
        p256ecdsa = self.__decode_webpush_b64(crypto_key_header.split("p256ecdsa=")[1].strip())
        dec_key = ec.derive_private_key(decrypt_params['privkey'], ec.SECP256R1(), default_backend())
        decrypted = http_ece.decrypt(
            data,
            salt = salt,
            key = p256ecdsa,
            private_key = dec_key, 
            dh = dhparams, 
            auth_secret=decrypt_params['auth'],
            keylabel = "P-256",
            version = "aesgcm"
        )
        
        return json.loads(decrypted.decode('utf-8'), object_hook = Mastodon.__json_hooks)
   
    ###
    # Blurhash utilities
    ### 

def fill_and_store(self, curve=None):
        curve = curve or ec.SECP256R1
        self.key = ec.generate_private_key(curve(), default_backend())
        self.pubkey = self.key.public_key() 

def validate_key_parameters(key_size=None, key_type='RSA', ecc_curve=None):
    """Validate parameters for private key generation and return sanitized values.

    This function can be used to fail early if invalid parameters are passed, before the private key is
    generated.

    >>> validate_key_parameters()  # defaults
    (1024, 'RSA', None)
    >>> validate_key_parameters(4096, 'ECC', None)  # doctest: +ELLIPSIS
    (None, 'ECC', <cryptography.hazmat.primitives.asymmetric.ec.SECP256R1 object at ...>)
    >>> validate_key_parameters(4000, 'RSA', None)
    Traceback (most recent call last):
        ...
    ValueError: 4000: Key size must be a power of two
    """
    if key_type is None:
        key_type = 'RSA'

    if key_type == 'ECC':
        key_size = None
        ecc_curve = parse_key_curve(ecc_curve)
    elif key_type in ['DSA', 'RSA']:
        if key_size is None:
            key_size = ca_settings.CA_DEFAULT_KEY_SIZE

        if not is_power2(key_size):
            raise ValueError("%s: Key size must be a power of two" % key_size)
        elif key_size < ca_settings.CA_MIN_KEY_SIZE:
            raise ValueError("%s: Key size must be least %s bits" % (
                key_size, ca_settings.CA_MIN_KEY_SIZE))
    else:
        raise ValueError('%s: Unknown key type' % key_type)

    return key_size, key_type, ecc_curve 

def test_key_pem(enclave_keys_dir):
    private_key = load_private_key(enclave_keys_dir / 'key.pem')
    assert isinstance(private_key, ec.EllipticCurvePrivateKey)
    assert private_key.key_size == 256

    public_key = private_key.public_key()
    assert isinstance(public_key.curve, ec.SECP256R1)
    assert public_key.key_size == 256 

def test_cryptography_sig_component_length(algorithm, expected_length):
    # Put mapping inside here to avoid more complex handling for test runs that do not have pyca/cryptography
    mapping = {
        ALGORITHMS.ES256: CryptographyEc.SECP256R1,
        ALGORITHMS.ES384: CryptographyEc.SECP384R1,
        ALGORITHMS.ES512: CryptographyEc.SECP521R1,
    }
    key = CryptographyECKey(
        CryptographyEc.generate_private_key(mapping[algorithm](), backend=CryptographyBackend()),
        algorithm
    )
    assert key._sig_component_length() == expected_length 

def generate_cert(device_id):
    private_key = ec.generate_private_key(
        ec.SECP256R1(), default_backend()
    )
    builder = x509.CertificateSigningRequestBuilder()

    builder = builder.subject_name(x509.Name([
        x509.NameAttribute(NameOID.COMMON_NAME, u'{}'.format(device_id)),
        x509.NameAttribute(NameOID.COUNTRY_NAME, u'UK'),
        x509.NameAttribute(NameOID.STATE_OR_PROVINCE_NAME, u'London'),
        x509.NameAttribute(NameOID.ORGANIZATION_NAME, u'Web of Trusted Things, Ltd'),
    ]))

    builder = builder.add_extension(
        x509.SubjectAlternativeName(
            [x509.DNSName(u'{}'.format(device_id))]
        ),
        critical=False
    )

    csr = builder.sign(private_key, hashes.SHA256(), default_backend())

    serialized_private_key = private_key.private_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PrivateFormat.PKCS8,
        encryption_algorithm=serialization.NoEncryption(),
    )
    serialized_csr = csr.public_bytes(serialization.Encoding.PEM)

    return {
        'csr': serialized_csr.decode(),
        'key': serialized_private_key.decode()
    } 

def _get_curve_by_name(self, name):
        if name == 'P-256':
            return ec.SECP256R1()
        elif name == 'P-384':
            return ec.SECP384R1()
        elif name == 'P-521':
            return ec.SECP521R1()
        elif name == 'secp256k1':
            return ec.SECP256K1()
        elif name in _OKP_CURVES_TABLE:
            return name
        else:
            raise InvalidJWKValue('Unknown Elliptic Curve Type') 

def get_new_private_key_in_pem_format(self):
        private_key = ec.generate_private_key(
            ec.SECP256R1(), default_backend())
        return private_key.private_bytes(
            encoding=serialization.Encoding.PEM,
            format=serialization.PrivateFormat.TraditionalOpenSSL,
            encryption_algorithm=serialization.NoEncryption()
        ) 

def fill_and_store(self, curve=None):
        curve = curve or ec.SECP256R1
        private_key = ec.generate_private_key(curve(), default_backend())
        self.pubkey = private_key.public_key() 

def _openssh_public_key_bytes(self, key):
        if isinstance(key, rsa.RSAPublicKey):
            public_numbers = key.public_numbers()
            return b"ssh-rsa " + base64.b64encode(
                serialization._ssh_write_string(b"ssh-rsa") +
                serialization._ssh_write_mpint(public_numbers.e) +
                serialization._ssh_write_mpint(public_numbers.n)
            )
        elif isinstance(key, dsa.DSAPublicKey):
            public_numbers = key.public_numbers()
            parameter_numbers = public_numbers.parameter_numbers
            return b"ssh-dss " + base64.b64encode(
                serialization._ssh_write_string(b"ssh-dss") +
                serialization._ssh_write_mpint(parameter_numbers.p) +
                serialization._ssh_write_mpint(parameter_numbers.q) +
                serialization._ssh_write_mpint(parameter_numbers.g) +
                serialization._ssh_write_mpint(public_numbers.y)
            )
        else:
            assert isinstance(key, ec.EllipticCurvePublicKey)
            public_numbers = key.public_numbers()
            try:
                curve_name = {
                    ec.SECP256R1: b"nistp256",
                    ec.SECP384R1: b"nistp384",
                    ec.SECP521R1: b"nistp521",
                }[type(public_numbers.curve)]
            except KeyError:
                raise ValueError(
                    "Only SECP256R1, SECP384R1, and SECP521R1 curves are "
                    "supported by the SSH public key format"
                )
            return b"ecdsa-sha2-" + curve_name + b" " + base64.b64encode(
                serialization._ssh_write_string(b"ecdsa-sha2-" + curve_name) +
                serialization._ssh_write_string(curve_name) +
                serialization._ssh_write_string(public_numbers.encode_point())
            ) 

def _openssh_public_key_bytes(self, key):
        if isinstance(key, rsa.RSAPublicKey):
            public_numbers = key.public_numbers()
            return b"ssh-rsa " + base64.b64encode(
                serialization._ssh_write_string(b"ssh-rsa") +
                serialization._ssh_write_mpint(public_numbers.e) +
                serialization._ssh_write_mpint(public_numbers.n)
            )
        elif isinstance(key, dsa.DSAPublicKey):
            public_numbers = key.public_numbers()
            parameter_numbers = public_numbers.parameter_numbers
            return b"ssh-dss " + base64.b64encode(
                serialization._ssh_write_string(b"ssh-dss") +
                serialization._ssh_write_mpint(parameter_numbers.p) +
                serialization._ssh_write_mpint(parameter_numbers.q) +
                serialization._ssh_write_mpint(parameter_numbers.g) +
                serialization._ssh_write_mpint(public_numbers.y)
            )
        else:
            assert isinstance(key, ec.EllipticCurvePublicKey)
            public_numbers = key.public_numbers()
            try:
                curve_name = {
                    ec.SECP256R1: b"nistp256",
                    ec.SECP384R1: b"nistp384",
                    ec.SECP521R1: b"nistp521",
                }[type(public_numbers.curve)]
            except KeyError:
                raise ValueError(
                    "Only SECP256R1, SECP384R1, and SECP521R1 curves are "
                    "supported by the SSH public key format"
                )
            return b"ecdsa-sha2-" + curve_name + b" " + base64.b64encode(
                serialization._ssh_write_string(b"ecdsa-sha2-" + curve_name) +
                serialization._ssh_write_string(curve_name) +
                serialization._ssh_write_string(public_numbers.encode_point())
            ) 

def test_disconnectKEX_ECDH_REPLYBadSignature(self):
        """
        Test that KEX_ECDH_REPLY disconnects if the signature is bad.
        """
        kexmsg = (
            b"\xAA" * 16 +
            common.NS(b'ecdh-sha2-nistp256') +
            common.NS(b'ssh-rsa') +
            common.NS(b'aes256-ctr') +
            common.NS(b'aes256-ctr') +
            common.NS(b'hmac-sha1') +
            common.NS(b'hmac-sha1') +
            common.NS(b'none') +
            common.NS(b'none') +
            common.NS(b'') +
            common.NS(b'') +
            b'\x00' + b'\x00\x00\x00\x00')

        self.proto.ssh_KEXINIT(kexmsg)

        self.proto.dataReceived(b"SSH-2.0-OpenSSH\r\n")

        self.proto.ecPriv = ec.generate_private_key(ec.SECP256R1(),
                                                    default_backend())
        self.proto.ecPub = self.proto.ecPriv.public_key()

        # Generate the private key
        thisPriv = ec.generate_private_key(ec.SECP256R1(), default_backend())
        # Get the public key
        thisPub = thisPriv.public_key()
        encPub = thisPub.public_numbers().encode_point()
        self.proto.curve = ec.SECP256R1()

        self.proto.kexAlg = b'ecdh-sha2-nistp256'

        self.proto._ssh_KEX_ECDH_REPLY(
            common.NS(MockFactory().getPublicKeys()[b'ssh-rsa'].blob()) +
            common.NS(encPub) + common.NS(b'bad-signature'))

        self.checkDisconnected(transport.DISCONNECT_KEY_EXCHANGE_FAILED) 

def test_disconnectKEX_ECDH_REPLYBadSignature(self):
        """
        Test that KEX_ECDH_REPLY disconnects if the signature is bad.
        """
        kexmsg = (
            b"\xAA" * 16 +
            common.NS(b'ecdh-sha2-nistp256') +
            common.NS(b'ssh-rsa') +
            common.NS(b'aes256-ctr') +
            common.NS(b'aes256-ctr') +
            common.NS(b'hmac-sha1') +
            common.NS(b'hmac-sha1') +
            common.NS(b'none') +
            common.NS(b'none') +
            common.NS(b'') +
            common.NS(b'') +
            b'\x00' + b'\x00\x00\x00\x00')

        self.proto.ssh_KEXINIT(kexmsg)

        self.proto.dataReceived(b"SSH-2.0-OpenSSH\r\n")

        self.proto.ecPriv = ec.generate_private_key(ec.SECP256R1(),
                                                    default_backend())
        self.proto.ecPub = self.proto.ecPriv.public_key()

        # Generate the private key
        thisPriv = ec.generate_private_key(ec.SECP256R1(), default_backend())
        # Get the public key
        thisPub = thisPriv.public_key()
        encPub = thisPub.public_numbers().encode_point()
        self.proto.curve = ec.SECP256R1()

        self.proto.kexAlg = b'ecdh-sha2-nistp256'

        self.proto._ssh_KEX_ECDH_REPLY(
             common.NS(MockFactory().getPublicKeys()[b'ssh-rsa'].blob()) +
                       common.NS(encPub) + common.NS(b'bad-signature'))

        self.checkDisconnected(transport.DISCONNECT_KEY_EXCHANGE_FAILED) 

def _load_ssh_ecdsa_public_key(expected_key_type, decoded_data, backend):
    curve_name, rest = _read_next_string(decoded_data)
    data, rest = _read_next_string(rest)

    if expected_key_type != b"ecdsa-sha2-" + curve_name:
        raise ValueError(
            'Key header and key body contain different key type values.'
        )

    if rest:
        raise ValueError('Key body contains extra bytes.')

    curve = {
        b"nistp256": ec.SECP256R1,
        b"nistp384": ec.SECP384R1,
        b"nistp521": ec.SECP521R1,
    }[curve_name]()

    if six.indexbytes(data, 0) != 4:
        raise NotImplementedError(
            "Compressed elliptic curve points are not supported"
        )

    # key_size is in bits, and sometimes it's not evenly divisible by 8, so we
    # add 7 to round up the number of bytes.
    if len(data) != 1 + 2 * ((curve.key_size + 7) // 8):
        raise ValueError("Malformed key bytes")

    x = utils.int_from_bytes(
        data[1:1 + (curve.key_size + 7) // 8], byteorder='big'
    )
    y = utils.int_from_bytes(
        data[1 + (curve.key_size + 7) // 8:], byteorder='big'
    )
    return ec.EllipticCurvePublicNumbers(x, y, curve).public_key(backend) 

def dummy_generate_key_pair(obj):
    private_key_value = 94761803665136558137557783047955027733968423115106677159790289642479432803037
    public_key_numbers = "042bdab212fa8ba1b7c843301682a4db424d307246c7e1e6083c41d9ca7b098bf30b3d63e2ec6278488c135360456cc054b3444ecc45998c08894cbc1370f5f989"
    public_key_numbers_obj = ec.EllipticCurvePublicNumbers.from_encoded_point(ec.SECP256R1(), unhexlify(public_key_numbers))
    obj.P = ec.EllipticCurvePrivateNumbers(private_value=private_key_value, public_numbers=public_key_numbers_obj).private_key(default_backend())
    if obj.transport.server_mode:
        obj.Q_S = ec.EllipticCurvePublicNumbers.from_encoded_point(ec.SECP256R1(), unhexlify(public_key_numbers)).public_key(default_backend())
        return
    obj.Q_C = ec.EllipticCurvePublicNumbers.from_encoded_point(ec.SECP256R1(), unhexlify(public_key_numbers)).public_key(default_backend())