diff options
Diffstat (limited to 'frozen_deps/ecdsa/curves.py')
| -rw-r--r-- | frozen_deps/ecdsa/curves.py | 329 |
1 files changed, 324 insertions, 5 deletions
diff --git a/frozen_deps/ecdsa/curves.py b/frozen_deps/ecdsa/curves.py index 9a10380..1119ee5 100644 --- a/frozen_deps/ecdsa/curves.py +++ b/frozen_deps/ecdsa/curves.py @@ -1,7 +1,9 @@ from __future__ import division -from . import der, ecdsa -from .util import orderlen +from six import PY2 +from . import der, ecdsa, ellipticcurve, eddsa +from .util import orderlen, number_to_string, string_to_number +from ._compat import normalise_bytes, bit_length # orderlen was defined in this module previously, so keep it in __all__, @@ -10,6 +12,10 @@ __all__ = [ "UnknownCurveError", "orderlen", "Curve", + "SECP112r1", + "SECP112r2", + "SECP128r1", + "SECP160r1", "NIST192p", "NIST224p", "NIST256p", @@ -17,6 +23,7 @@ __all__ = [ "NIST521p", "curves", "find_curve", + "curve_by_name", "SECP256k1", "BRAINPOOLP160r1", "BRAINPOOLP192r1", @@ -25,9 +32,17 @@ __all__ = [ "BRAINPOOLP320r1", "BRAINPOOLP384r1", "BRAINPOOLP512r1", + "PRIME_FIELD_OID", + "CHARACTERISTIC_TWO_FIELD_OID", + "Ed25519", + "Ed448", ] +PRIME_FIELD_OID = (1, 2, 840, 10045, 1, 1) +CHARACTERISTIC_TWO_FIELD_OID = (1, 2, 840, 10045, 1, 2) + + class UnknownCurveError(Exception): pass @@ -39,15 +54,262 @@ class Curve: self.curve = curve self.generator = generator self.order = generator.order() - self.baselen = orderlen(self.order) - self.verifying_key_length = 2 * self.baselen + if isinstance(curve, ellipticcurve.CurveEdTw): + # EdDSA keys are special in that both private and public + # are the same size (as it's defined only with compressed points) + + # +1 for the sign bit and then round up + self.baselen = (bit_length(curve.p()) + 1 + 7) // 8 + self.verifying_key_length = self.baselen + else: + self.baselen = orderlen(self.order) + self.verifying_key_length = 2 * orderlen(curve.p()) self.signature_length = 2 * self.baselen self.oid = oid - self.encoded_oid = der.encode_oid(*oid) + if oid: + self.encoded_oid = der.encode_oid(*oid) + + def __eq__(self, other): + if isinstance(other, Curve): + return ( + self.curve == other.curve and self.generator == other.generator + ) + return NotImplemented + + def __ne__(self, other): + return not self == other def __repr__(self): return self.name + def to_der(self, encoding=None, point_encoding="uncompressed"): + """Serialise the curve parameters to binary string. + + :param str encoding: the format to save the curve parameters in. + Default is ``named_curve``, with fallback being the ``explicit`` + if the OID is not set for the curve. + :param str point_encoding: the point encoding of the generator when + explicit curve encoding is used. Ignored for ``named_curve`` + format. + + :return: DER encoded ECParameters structure + :rtype: bytes + """ + if encoding is None: + if self.oid: + encoding = "named_curve" + else: + encoding = "explicit" + + if encoding not in ("named_curve", "explicit"): + raise ValueError( + "Only 'named_curve' and 'explicit' encodings supported" + ) + + if encoding == "named_curve": + if not self.oid: + raise UnknownCurveError( + "Can't encode curve using named_curve encoding without " + "associated curve OID" + ) + return der.encode_oid(*self.oid) + elif isinstance(self.curve, ellipticcurve.CurveEdTw): + assert encoding == "explicit" + raise UnknownCurveError( + "Twisted Edwards curves don't support explicit encoding" + ) + + # encode the ECParameters sequence + curve_p = self.curve.p() + version = der.encode_integer(1) + field_id = der.encode_sequence( + der.encode_oid(*PRIME_FIELD_OID), der.encode_integer(curve_p) + ) + curve = der.encode_sequence( + der.encode_octet_string( + number_to_string(self.curve.a() % curve_p, curve_p) + ), + der.encode_octet_string( + number_to_string(self.curve.b() % curve_p, curve_p) + ), + ) + base = der.encode_octet_string(self.generator.to_bytes(point_encoding)) + order = der.encode_integer(self.generator.order()) + seq_elements = [version, field_id, curve, base, order] + if self.curve.cofactor(): + cofactor = der.encode_integer(self.curve.cofactor()) + seq_elements.append(cofactor) + + return der.encode_sequence(*seq_elements) + + def to_pem(self, encoding=None, point_encoding="uncompressed"): + """ + Serialise the curve parameters to the :term:`PEM` format. + + :param str encoding: the format to save the curve parameters in. + Default is ``named_curve``, with fallback being the ``explicit`` + if the OID is not set for the curve. + :param str point_encoding: the point encoding of the generator when + explicit curve encoding is used. Ignored for ``named_curve`` + format. + + :return: PEM encoded ECParameters structure + :rtype: str + """ + return der.topem( + self.to_der(encoding, point_encoding), "EC PARAMETERS" + ) + + @staticmethod + def from_der(data, valid_encodings=None): + """Decode the curve parameters from DER file. + + :param data: the binary string to decode the parameters from + :type data: :term:`bytes-like object` + :param valid_encodings: set of names of allowed encodings, by default + all (set by passing ``None``), supported ones are ``named_curve`` + and ``explicit`` + :type valid_encodings: :term:`set-like object` + """ + if not valid_encodings: + valid_encodings = set(("named_curve", "explicit")) + if not all(i in ["named_curve", "explicit"] for i in valid_encodings): + raise ValueError( + "Only named_curve and explicit encodings supported" + ) + data = normalise_bytes(data) + if not der.is_sequence(data): + if "named_curve" not in valid_encodings: + raise der.UnexpectedDER( + "named_curve curve parameters not allowed" + ) + oid, empty = der.remove_object(data) + if empty: + raise der.UnexpectedDER("Unexpected data after OID") + return find_curve(oid) + + if "explicit" not in valid_encodings: + raise der.UnexpectedDER("explicit curve parameters not allowed") + + seq, empty = der.remove_sequence(data) + if empty: + raise der.UnexpectedDER( + "Unexpected data after ECParameters structure" + ) + # decode the ECParameters sequence + version, rest = der.remove_integer(seq) + if version != 1: + raise der.UnexpectedDER("Unknown parameter encoding format") + field_id, rest = der.remove_sequence(rest) + curve, rest = der.remove_sequence(rest) + base_bytes, rest = der.remove_octet_string(rest) + order, rest = der.remove_integer(rest) + cofactor = None + if rest: + # the ASN.1 specification of ECParameters allows for future + # extensions of the sequence, so ignore the remaining bytes + cofactor, _ = der.remove_integer(rest) + + # decode the ECParameters.fieldID sequence + field_type, rest = der.remove_object(field_id) + if field_type == CHARACTERISTIC_TWO_FIELD_OID: + raise UnknownCurveError("Characteristic 2 curves unsupported") + if field_type != PRIME_FIELD_OID: + raise UnknownCurveError( + "Unknown field type: {0}".format(field_type) + ) + prime, empty = der.remove_integer(rest) + if empty: + raise der.UnexpectedDER( + "Unexpected data after ECParameters.fieldID.Prime-p element" + ) + + # decode the ECParameters.curve sequence + curve_a_bytes, rest = der.remove_octet_string(curve) + curve_b_bytes, rest = der.remove_octet_string(rest) + # seed can be defined here, but we don't parse it, so ignore `rest` + + curve_a = string_to_number(curve_a_bytes) + curve_b = string_to_number(curve_b_bytes) + + curve_fp = ellipticcurve.CurveFp(prime, curve_a, curve_b, cofactor) + + # decode the ECParameters.base point + + base = ellipticcurve.PointJacobi.from_bytes( + curve_fp, + base_bytes, + valid_encodings=("uncompressed", "compressed", "hybrid"), + order=order, + generator=True, + ) + tmp_curve = Curve("unknown", curve_fp, base, None) + + # if the curve matches one of the well-known ones, use the well-known + # one in preference, as it will have the OID and name associated + for i in curves: + if tmp_curve == i: + return i + return tmp_curve + + @classmethod + def from_pem(cls, string, valid_encodings=None): + """Decode the curve parameters from PEM file. + + :param str string: the text string to decode the parameters from + :param valid_encodings: set of names of allowed encodings, by default + all (set by passing ``None``), supported ones are ``named_curve`` + and ``explicit`` + :type valid_encodings: :term:`set-like object` + """ + if not PY2 and isinstance(string, str): # pragma: no branch + string = string.encode() + + ec_param_index = string.find(b"-----BEGIN EC PARAMETERS-----") + if ec_param_index == -1: + raise der.UnexpectedDER("EC PARAMETERS PEM header not found") + + return cls.from_der( + der.unpem(string[ec_param_index:]), valid_encodings + ) + + +# the SEC curves +SECP112r1 = Curve( + "SECP112r1", + ecdsa.curve_112r1, + ecdsa.generator_112r1, + (1, 3, 132, 0, 6), + "secp112r1", +) + + +SECP112r2 = Curve( + "SECP112r2", + ecdsa.curve_112r2, + ecdsa.generator_112r2, + (1, 3, 132, 0, 7), + "secp112r2", +) + + +SECP128r1 = Curve( + "SECP128r1", + ecdsa.curve_128r1, + ecdsa.generator_128r1, + (1, 3, 132, 0, 28), + "secp128r1", +) + + +SECP160r1 = Curve( + "SECP160r1", + ecdsa.curve_160r1, + ecdsa.generator_160r1, + (1, 3, 132, 0, 8), + "secp160r1", +) + # the NIST curves NIST192p = Curve( @@ -167,6 +429,23 @@ BRAINPOOLP512r1 = Curve( ) +Ed25519 = Curve( + "Ed25519", + eddsa.curve_ed25519, + eddsa.generator_ed25519, + (1, 3, 101, 112), +) + + +Ed448 = Curve( + "Ed448", + eddsa.curve_ed448, + eddsa.generator_ed448, + (1, 3, 101, 113), +) + + +# no order in particular, but keep previously added curves first curves = [ NIST192p, NIST224p, @@ -181,10 +460,26 @@ curves = [ BRAINPOOLP320r1, BRAINPOOLP384r1, BRAINPOOLP512r1, + SECP112r1, + SECP112r2, + SECP128r1, + SECP160r1, + Ed25519, + Ed448, ] def find_curve(oid_curve): + """Select a curve based on its OID + + :param tuple[int,...] oid_curve: ASN.1 Object Identifier of the + curve to return, like ``(1, 2, 840, 10045, 3, 1, 7)`` for ``NIST256p``. + + :raises UnknownCurveError: When the oid doesn't match any of the supported + curves + + :rtype: ~ecdsa.curves.Curve + """ for c in curves: if c.oid == oid_curve: return c @@ -192,3 +487,27 @@ def find_curve(oid_curve): "I don't know about the curve with oid %s." "I only know about these: %s" % (oid_curve, [c.name for c in curves]) ) + + +def curve_by_name(name): + """Select a curve based on its name. + + Returns a :py:class:`~ecdsa.curves.Curve` object with a ``name`` name. + Note that ``name`` is case-sensitve. + + :param str name: Name of the curve to return, like ``NIST256p`` or + ``prime256v1`` + + :raises UnknownCurveError: When the name doesn't match any of the supported + curves + + :rtype: ~ecdsa.curves.Curve + """ + for c in curves: + if name == c.name or (c.openssl_name and name == c.openssl_name): + return c + raise UnknownCurveError( + "Curve with name {0!r} unknown, only curves supported: {1}".format( + name, [c.name for c in curves] + ) + ) |