diff options
Diffstat (limited to 'pyecsca/ec/curves.py')
| -rw-r--r-- | pyecsca/ec/curves.py | 92 |
1 files changed, 51 insertions, 41 deletions
diff --git a/pyecsca/ec/curves.py b/pyecsca/ec/curves.py index 1bb2161..d490b74 100644 --- a/pyecsca/ec/curves.py +++ b/pyecsca/ec/curves.py @@ -1,15 +1,18 @@ -from public import public +import json +from os.path import join from typing import Mapping, Any +from pkg_resources import resource_listdir, resource_isdir, resource_stream +from public import public + from .coordinates import AffineCoordinateModel from .curve import EllipticCurve -from .params import DomainParameters from .mod import Mod from .model import (ShortWeierstrassModel, MontgomeryModel, TwistedEdwardsModel, EdwardsModel, CurveModel) +from .params import DomainParameters from .point import Point, InfinityPoint - SHORT_WEIERSTRASS: Mapping[str, Mapping[str, Any]] = { "brainpoolP160r1": { "p": 0xE95E4A5F737059DC60DFC7AD95B3D8139515620F, @@ -167,11 +170,12 @@ MONTGOMERY: Mapping[str, Mapping[str, Any]] = { EDWARDS: Mapping[str, Mapping[str, Any]] = { "ed448": { - "p": 2**448 - 2**224 - 1, + "p": 2 ** 448 - 2 ** 224 - 1, "c": 1, "d": 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffeffffffffffffffffffffffffffffffffffffffffffffffffffff6756, - "g": (0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa955555555555555555555555555555555555555555555555555555555, - 0xae05e9634ad7048db359d6205086c2b0036ed7a035884dd7b7e36d728ad8c4b80d6565833a2a3098bbbcb2bed1cda06bdaeafbcdea9386ed), + "g": ( + 0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa955555555555555555555555555555555555555555555555555555555, + 0xae05e9634ad7048db359d6205086c2b0036ed7a035884dd7b7e36d728ad8c4b80d6565833a2a3098bbbcb2bed1cda06bdaeafbcdea9386ed), "n": 0x3fffffffffffffffffffffffffffffffffffffffffffffffffffffff7cca23e9c44edb49aed63690216cc2728dc58f552378c292ab5844f3, "h": 4 } @@ -191,49 +195,55 @@ TWISTED_EDWARDS: Mapping[str, Mapping[str, Any]] = { @public -def get_curve(name: str, coords: str) -> DomainParameters: +def get_params(category: str, name: str, coords: str) -> DomainParameters: """ - Retrieve a curve from a set of stored parameters. + Retrieve a curve from a set of stored parameters. Uses the std-curves database at + https://github.com/J08nY/std-curves. + :param category: The category of the curve. :param name: The name of the curve. :param coords: The name of the coordinate system to use. :return: The curve. """ + listing = resource_listdir(__name__, "std") + categories = list(entry for entry in listing if resource_isdir(__name__, join("std", entry))) + if category not in categories: + raise ValueError("Category {} not found.".format(category)) + json_path = join("std", category, "curves.json") + with resource_stream(__name__, json_path) as f: + category_json = json.load(f) + for curve in category_json["curves"]: + if curve["name"] == name: + break + else: + raise ValueError("Curve {} not found in category {}.".format(name, category)) + if curve["field"]["type"] == "Binary": + raise ValueError("Binary field curves are currently not supported.") + model: CurveModel - if name in SHORT_WEIERSTRASS: - params = SHORT_WEIERSTRASS[name] + field = int(curve["field"]["p"], 16) + order = int(curve["order"], 16) + cofactor = int(curve["cofactor"], 16) + if curve["form"] == "Weierstrass": model = ShortWeierstrassModel() - coord_model = model.coordinates[coords] - curve = EllipticCurve(model, coord_model, params["p"], dict(a=params["a"], b=params["b"])) - affine = Point(AffineCoordinateModel(model), x=Mod(params["g"][0], params["p"]), - y=Mod(params["g"][1], params["p"])) - generator = Point.from_affine(coord_model, affine) - return DomainParameters(curve, generator, InfinityPoint(coord_model), params["n"], params["h"]) - elif name in MONTGOMERY: - params = MONTGOMERY[name] + param_names = ["a", "b"] + elif curve["form"] == "Montgomery": model = MontgomeryModel() - coord_model = model.coordinates[coords] - curve = EllipticCurve(model, coord_model, params["p"], dict(a=params["a"], b=params["b"])) - generator = Point(coord_model, X=Mod(params["x"], params["p"]), - Z=Mod(params["z"], params["p"])) - return DomainParameters(curve, generator, InfinityPoint(coord_model), params["n"], params["h"]) - elif name in TWISTED_EDWARDS: - params = TWISTED_EDWARDS[name] - model = TwistedEdwardsModel() - coord_model = model.coordinates[coords] - curve = EllipticCurve(model, coord_model, params["p"], dict(a=params["a"], d=params["d"])) - affine = Point(AffineCoordinateModel(model), x=Mod(params["g"][0], params["p"]), - y=Mod(params["g"][1], params["p"])) - generator = Point.from_affine(coord_model, affine) - return DomainParameters(curve, generator, InfinityPoint(coord_model), params["n"], params["h"]) - elif name in EDWARDS: - params = EDWARDS[name] + param_names = ["a", "b"] + elif curve["form"] == "Edwards": model = EdwardsModel() - coord_model = model.coordinates[coords] - curve = EllipticCurve(model, coord_model, params["p"], dict(c=params["c"], d=params["d"])) - affine = Point(AffineCoordinateModel(model), x=Mod(params["g"][0], params["p"]), - y=Mod(params["g"][1], params["p"])) - generator = Point.from_affine(coord_model, affine) - return DomainParameters(curve, generator, InfinityPoint(coord_model), params["n"], params["h"]) + param_names = ["c", "d"] + elif curve["form"] == "TwistedEdwards": + model = TwistedEdwardsModel() + param_names = ["a", "d"] else: - raise ValueError("Unknown curve: {}".format(name)) + raise ValueError("Unknown curve model.") + if coords not in model.coordinates: + raise ValueError("Coordinate model not supported for curve.") + coord_model = model.coordinates[coords] + params = {name: int(curve["params"][name], 16) for name in param_names} + elliptic_curve = EllipticCurve(model, coord_model, field, params) + affine = Point(AffineCoordinateModel(model), x=Mod(int(curve["generator"]["x"], 16), field), + y=Mod(int(curve["generator"]["y"], 16), field)) + generator = Point.from_affine(coord_model, affine) + return DomainParameters(elliptic_curve, generator, InfinityPoint(coord_model), order, cofactor) |