Python cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers() Examples

def write_private_key(self, file_obj, password=None):
        key = dsa.DSAPrivateNumbers(
            x=self.x,
            public_numbers=dsa.DSAPublicNumbers(
                y=self.y,
                parameter_numbers=dsa.DSAParameterNumbers(
                    p=self.p,
                    q=self.q,
                    g=self.g
                )
            )
        ).private_key(backend=default_backend())

        self._write_private_key(
            file_obj,
            key,
            serialization.PrivateFormat.TraditionalOpenSSL,
            password=password
        ) 

def write_private_key_file(self, filename, password=None):
        key = dsa.DSAPrivateNumbers(
            x=self.x,
            public_numbers=dsa.DSAPublicNumbers(
                y=self.y,
                parameter_numbers=dsa.DSAParameterNumbers(
                    p=self.p,
                    q=self.q,
                    g=self.g
                )
            )
        ).private_key(backend=default_backend())

        self._write_private_key_file(
            filename,
            key,
            serialization.PrivateFormat.TraditionalOpenSSL,
            password=password
        ) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def verify_ssh_sig(self, data, msg):
        if len(msg.asbytes()) == 40:
            # spies.com bug: signature has no header
            sig = msg.asbytes()
        else:
            kind = msg.get_text()
            if kind != 'ssh-dss':
                return 0
            sig = msg.get_binary()

        # pull out (r, s) which are NOT encoded as mpints
        sigR = util.inflate_long(sig[:20], 1)
        sigS = util.inflate_long(sig[20:], 1)

        signature = encode_dss_signature(sigR, sigS)

        key = dsa.DSAPublicNumbers(
            y=self.y,
            parameter_numbers=dsa.DSAParameterNumbers(
                p=self.p,
                q=self.q,
                g=self.g
            )
        ).public_key(backend=default_backend())
        verifier = key.verifier(signature, hashes.SHA1())
        verifier.update(data)
        try:
            verifier.verify()
        except InvalidSignature:
            return False
        else:
            return True 

def sign_ssh_data(self, data):
        key = dsa.DSAPrivateNumbers(
            x=self.x,
            public_numbers=dsa.DSAPublicNumbers(
                y=self.y,
                parameter_numbers=dsa.DSAParameterNumbers(
                    p=self.p,
                    q=self.q,
                    g=self.g
                )
            )
        ).private_key(backend=default_backend())
        signer = key.signer(hashes.SHA1())
        signer.update(data)
        r, s = decode_dss_signature(signer.finalize())

        m = Message()
        m.add_string('ssh-dss')
        # apparently, in rare cases, r or s may be shorter than 20 bytes!
        rstr = util.deflate_long(r, 0)
        sstr = util.deflate_long(s, 0)
        if len(rstr) < 20:
            rstr = zero_byte * (20 - len(rstr)) + rstr
        if len(sstr) < 20:
            sstr = zero_byte * (20 - len(sstr)) + sstr
        m.add_string(rstr + sstr)
        return m 

def __privkey__(self):
        params = dsa.DSAParameterNumbers(self.p, self.q, self.g)
        pn = dsa.DSAPublicNumbers(self.y, params)
        return dsa.DSAPrivateNumbers(self.x, pn).private_key(default_backend()) 

def __pubkey__(self):
        params = dsa.DSAParameterNumbers(self.p, self.q, self.g)
        return dsa.DSAPublicNumbers(self.y, params).public_key(default_backend()) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _read_next_mpint(decoded_data)
    q, rest = _read_next_mpint(rest)
    g, rest = _read_next_mpint(rest)
    y, rest = _read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _fromDSAComponents(cls, y, p, q, g, x=None):
        """
        Build a key from DSA numerical components.

        @type y: L{int}
        @param y: The 'y' DSA variable.

        @type p: L{int}
        @param p: The 'p' DSA variable.

        @type q: L{int}
        @param q: The 'q' DSA variable.

        @type g: L{int}
        @param g: The 'g' DSA variable.

        @type x: L{int} or L{None}
        @param x: The 'x' DSA variable (optional for a public key)

        @rtype: L{Key}
        @return: A DSA key constructed from the values as given.
        """
        publicNumbers = dsa.DSAPublicNumbers(
            y=y, parameter_numbers=dsa.DSAParameterNumbers(p=p, q=q, g=g))
        if x is None:
            # We have public components.
            keyObject = publicNumbers.public_key(default_backend())
        else:
            privateNumbers = dsa.DSAPrivateNumbers(
                x=x, public_numbers=publicNumbers)
            keyObject = privateNumbers.private_key(default_backend())

        return cls(keyObject) 

def _process_ssh_dss(self, data):
        """Parses ssh-dsa public keys."""
        data_fields = {}
        current_position = 0
        for item in ("p", "q", "g", "y"):
            current_position, value = self._unpack_by_int(data, current_position)
            data_fields[item] = self._parse_long(value)

        q_bits = self._bits_in_number(data_fields["q"])
        p_bits = self._bits_in_number(data_fields["p"])
        if q_bits != self.DSA_N_LENGTH:
            raise InvalidKeyError("Incorrect DSA key parameters: bits(p)=%s, q=%s" % (self.bits, q_bits))
        if self.strict_mode:
            min_length = self.DSA_MIN_LENGTH_STRICT
            max_length = self.DSA_MAX_LENGTH_STRICT
        else:
            min_length = self.DSA_MIN_LENGTH_LOOSE
            max_length = self.DSA_MAX_LENGTH_LOOSE
        if p_bits < min_length:
            raise TooShortKeyError("%s key can not be shorter than %s bits (was %s)" % (self.key_type.decode(), min_length, p_bits))
        if p_bits > max_length:
            raise TooLongKeyError(
                "%s key data can not be longer than %s bits (was %s)" % (self.key_type.decode(), max_length, p_bits)
            )

        dsa_parameters = DSAParameterNumbers(data_fields["p"], data_fields["q"], data_fields["g"])
        self.dsa = DSAPublicNumbers(data_fields["y"], dsa_parameters).public_key(default_backend())
        self.bits = self.dsa.key_size

        return current_position 

def create_pubkey(pubkey_info):
  """
  <Purpose>
    Create and return a DSAPublicKey object from the passed pubkey_info
    using pyca/cryptography.

  <Arguments>
    pubkey_info:
            The DSA pubkey info dictionary as specified by
            securesystemslib.formats.GPG_DSA_PUBKEY_SCHEMA

  <Exceptions>
    securesystemslib.exceptions.FormatError if
      pubkey_info does not match securesystemslib.formats.GPG_DSA_PUBKEY_SCHEMA

    securesystemslib.exceptions.UnsupportedLibraryError if
      the cryptography module is not available

  <Returns>
    A cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey based on the
    passed pubkey_info.

  """
  if not CRYPTO: # pragma: no cover
    raise securesystemslib.exceptions.UnsupportedLibraryError(NO_CRYPTO_MSG)

  securesystemslib.formats.GPG_DSA_PUBKEY_SCHEMA.check_match(pubkey_info)

  y = int(pubkey_info['keyval']['public']['y'], 16)
  g = int(pubkey_info['keyval']['public']['g'], 16)
  p = int(pubkey_info['keyval']['public']['p'], 16)
  q = int(pubkey_info['keyval']['public']['q'], 16)
  parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
  pubkey = dsa.DSAPublicNumbers(y, parameter_numbers).public_key(
      backends.default_backend())

  return pubkey 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _load_ssh_dss_public_key(key_type, decoded_data, backend):
    p, rest = _ssh_read_next_mpint(decoded_data)
    q, rest = _ssh_read_next_mpint(rest)
    g, rest = _ssh_read_next_mpint(rest)
    y, rest = _ssh_read_next_mpint(rest)

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

    parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
    public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)

    return public_numbers.public_key(backend) 

def _fromDSAComponents(cls, y, p, q, g, x=None):
        """
        Build a key from DSA numerical components.

        @type y: L{int}
        @param y: The 'y' DSA variable.

        @type p: L{int}
        @param p: The 'p' DSA variable.

        @type q: L{int}
        @param q: The 'q' DSA variable.

        @type g: L{int}
        @param g: The 'g' DSA variable.

        @type x: L{int} or L{None}
        @param x: The 'x' DSA variable (optional for a public key)

        @rtype: L{Key}
        @return: A DSA key constructed from the values as given.
        """
        publicNumbers = dsa.DSAPublicNumbers(
            y=y, parameter_numbers=dsa.DSAParameterNumbers(p=p, q=q, g=g))
        if x is None:
            # We have public components.
            keyObject = publicNumbers.public_key(default_backend())
        else:
            privateNumbers = dsa.DSAPrivateNumbers(
                x=x, public_numbers=publicNumbers)
            keyObject = privateNumbers.private_key(default_backend())

        return cls(keyObject) 

def _verify_signature_with_pubkey(self, signed_info_c14n, raw_signature, key_value, der_encoded_key_value,
                                      signature_alg):
        if der_encoded_key_value is not None:
            key = load_der_public_key(b64decode(der_encoded_key_value.text), backend=default_backend())
        if "ecdsa-" in signature_alg:
            if key_value is not None:
                ec_key_value = self._find(key_value, "ECKeyValue", namespace="dsig11")
                named_curve = self._find(ec_key_value, "NamedCurve", namespace="dsig11")
                public_key = self._find(ec_key_value, "PublicKey", namespace="dsig11")
                key_data = b64decode(public_key.text)[1:]
                x = bytes_to_long(key_data[:len(key_data)//2])
                y = bytes_to_long(key_data[len(key_data)//2:])
                curve_class = self.known_ecdsa_curves[named_curve.get("URI")]
                key = ec.EllipticCurvePublicNumbers(x=x, y=y, curve=curve_class()).public_key(backend=default_backend())
            elif not isinstance(key, ec.EllipticCurvePublicKey):
                raise InvalidInput("DER encoded key value does not match specified signature algorithm")
            dss_signature = self._encode_dss_signature(raw_signature, key.key_size)
            key.verify(
                dss_signature,
                data=signed_info_c14n,
                signature_algorithm=ec.ECDSA(
                    self._get_signature_digest_method(signature_alg)
                ),
            )
        elif "dsa-" in signature_alg:
            if key_value is not None:
                dsa_key_value = self._find(key_value, "DSAKeyValue")
                p = self._get_long(dsa_key_value, "P")
                q = self._get_long(dsa_key_value, "Q")
                g = self._get_long(dsa_key_value, "G", require=False)
                y = self._get_long(dsa_key_value, "Y")
                pn = dsa.DSAPublicNumbers(y=y, parameter_numbers=dsa.DSAParameterNumbers(p=p, q=q, g=g))
                key = pn.public_key(backend=default_backend())
            elif not isinstance(key, dsa.DSAPublicKey):
                raise InvalidInput("DER encoded key value does not match specified signature algorithm")
            # TODO: supply meaningful key_size_bits for signature length assertion
            dss_signature = self._encode_dss_signature(raw_signature, len(raw_signature) * 8 / 2)
            key.verify(dss_signature,
                       data=signed_info_c14n,
                       algorithm=self._get_signature_digest_method(signature_alg))
        elif "rsa-" in signature_alg:
            if key_value is not None:
                rsa_key_value = self._find(key_value, "RSAKeyValue")
                modulus = self._get_long(rsa_key_value, "Modulus")
                exponent = self._get_long(rsa_key_value, "Exponent")
                key = rsa.RSAPublicNumbers(e=exponent, n=modulus).public_key(backend=default_backend())
            elif not isinstance(key, rsa.RSAPublicKey):
                raise InvalidInput("DER encoded key value does not match specified signature algorithm")
            key.verify(raw_signature,
                       data=signed_info_c14n,
                       padding=PKCS1v15(),
                       algorithm=self._get_signature_digest_method(signature_alg))
        else:
            raise NotImplementedError() 

def _fromString_BLOB(cls, blob):
        """
        Return a public key object corresponding to this public key blob.
        The format of a RSA public key blob is::
            string 'ssh-rsa'
            integer e
            integer n

        The format of a DSA public key blob is::
            string 'ssh-dss'
            integer p
            integer q
            integer g
            integer y

        The format of ECDSA-SHA2-* public key blob is::
            string 'ecdsa-sha2-[identifier]'
            integer x
            integer y

            identifier is the standard NIST curve name.

        @type blob: L{bytes}
        @param blob: The key data.

        @return: A new key.
        @rtype: L{twisted.conch.ssh.keys.Key}
        @raises BadKeyError: if the key type (the first string) is unknown.
        """
        keyType, rest = common.getNS(blob)
        if keyType == b'ssh-rsa':
            e, n, rest = common.getMP(rest, 2)
            return cls(
                rsa.RSAPublicNumbers(e, n).public_key(default_backend()))
        elif keyType == b'ssh-dss':
            p, q, g, y, rest = common.getMP(rest, 4)
            return cls(
                dsa.DSAPublicNumbers(
                    y=y,
                    parameter_numbers=dsa.DSAParameterNumbers(
                        p=p,
                        q=q,
                        g=g
                    )
                ).public_key(default_backend())
            )
        elif keyType in _curveTable:
            return cls(
                ec.EllipticCurvePublicKey.from_encoded_point(
                    _curveTable[keyType], common.getNS(rest, 2)[1]
                )
            )
        else:
            raise BadKeyError('unknown blob type: %s' % (keyType,)) 

def _fromString_BLOB(cls, blob):
        """
        Return a public key object corresponding to this public key blob.
        The format of a RSA public key blob is::
            string 'ssh-rsa'
            integer e
            integer n

        The format of a DSA public key blob is::
            string 'ssh-dss'
            integer p
            integer q
            integer g
            integer y

        The format of ECDSA-SHA2-* public key blob is::
            string 'ecdsa-sha2-[identifier]'
            integer x
            integer y

            identifier is the standard NIST curve name.

        @type blob: L{bytes}
        @param blob: The key data.

        @return: A new key.
        @rtype: L{twisted.conch.ssh.keys.Key}
        @raises BadKeyError: if the key type (the first string) is unknown.
        """
        keyType, rest = common.getNS(blob)
        if keyType == b'ssh-rsa':
            e, n, rest = common.getMP(rest, 2)
            return cls(
                rsa.RSAPublicNumbers(e, n).public_key(default_backend()))
        elif keyType == b'ssh-dss':
            p, q, g, y, rest = common.getMP(rest, 4)
            return cls(
                dsa.DSAPublicNumbers(
                    y=y,
                    parameter_numbers=dsa.DSAParameterNumbers(
                        p=p,
                        q=q,
                        g=g
                    )
                ).public_key(default_backend())
            )
        elif keyType in _curveTable:
            # First we have to make an EllipticCuvePublicNumbers from the
            # provided curve and points,
            # then turn it into a public key object.
            return cls(
                ec.EllipticCurvePublicNumbers.from_encoded_point(
                      _curveTable[keyType],
                       common.getNS(rest, 2)[1]).public_key(default_backend()))
        else:
            raise BadKeyError('unknown blob type: %s' % (keyType,))