diff options
Diffstat (limited to 'pyecsca/ec/curve.py')
| -rw-r--r-- | pyecsca/ec/curve.py | 89 |
1 files changed, 61 insertions, 28 deletions
diff --git a/pyecsca/ec/curve.py b/pyecsca/ec/curve.py index 8a3c726..67feb60 100644 --- a/pyecsca/ec/curve.py +++ b/pyecsca/ec/curve.py @@ -1,4 +1,5 @@ """Provides an elliptic curve class.""" + from ast import Module from astunparse import unparse from copy import copy @@ -68,21 +69,21 @@ class EllipticCurve: """The neutral point on the curve.""" def __init__( - self, - model: CurveModel, - coordinate_model: CoordinateModel, - prime: int, - neutral: Point, - parameters: MutableMapping[str, Union[Mod, int]], + self, + model: CurveModel, + coordinate_model: CoordinateModel, + prime: int, + neutral: Point, + parameters: MutableMapping[str, Union[Mod, int]], ): if coordinate_model not in model.coordinates.values() and not isinstance( - coordinate_model, AffineCoordinateModel + coordinate_model, AffineCoordinateModel ): raise ValueError if ( - set(model.parameter_names) - .union(coordinate_model.parameters) - .symmetric_difference(parameters.keys()) + set(model.parameter_names) + .union(coordinate_model.parameters) + .symmetric_difference(parameters.keys()) ): raise ValueError self.model = model @@ -130,7 +131,7 @@ class EllipticCurve: if k.from_sympy(expr) != 0: raise_unsatisified_assumption( getconfig().ec.unsatisfied_coordinate_assumption_action, - f"Coordinate model {self.coordinate_model} has an unsatisifed assumption on the {param} parameter (0 = {expr})." + f"Coordinate model {self.coordinate_model} has an unsatisifed assumption on the {param} parameter (0 = {expr}).", ) def _execute_base_formulas(self, formulas: List[Module], *points: Point) -> Point: @@ -146,7 +147,9 @@ class EllipticCurve: } locls.update(self.parameters) for line in formulas: - exec(compile(line, "", mode="exec"), None, locls) # exec is OK here, skipcq: PYL-W0122 + exec( + compile(line, "", mode="exec"), None, locls + ) # exec is OK here, skipcq: PYL-W0122 if not isinstance(locls["x"], Mod): locls["x"] = mod(locls["x"], self.prime) if not isinstance(locls["y"], Mod): @@ -233,7 +236,9 @@ class EllipticCurve: return None locls = {**self.parameters} for line in self.model.base_neutral: - exec(compile(line, "", mode="exec"), None, locls) # exec is OK here, skipcq: PYL-W0122 + exec( + compile(line, "", mode="exec"), None, locls + ) # exec is OK here, skipcq: PYL-W0122 if not isinstance(locls["x"], Mod): locls["x"] = mod(locls["x"], self.prime) if not isinstance(locls["y"], Mod): @@ -269,7 +274,9 @@ class EllipticCurve: loc = {**self.parameters, **point.coords} else: loc = {**self.parameters, **point.to_affine().coords} - return eval(compile(self.model.equation, "", mode="eval"), loc) # eval is OK here, skipcq: PYL-W0123 + return eval( + compile(self.model.equation, "", mode="eval"), loc + ) # eval is OK here, skipcq: PYL-W0123 def to_coords(self, coordinate_model: CoordinateModel) -> "EllipticCurve": """ @@ -280,8 +287,13 @@ class EllipticCurve: """ if not isinstance(self.coordinate_model, AffineCoordinateModel): raise ValueError - return EllipticCurve(self.model, coordinate_model, self.prime, self.neutral.to_model(coordinate_model, self), - self.parameters) # type: ignore[arg-type] + return EllipticCurve( + self.model, + coordinate_model, + self.prime, + self.neutral.to_model(coordinate_model, self), + self.parameters, + ) # type: ignore[arg-type] def to_affine(self) -> "EllipticCurve": """ @@ -290,8 +302,13 @@ class EllipticCurve: :return: The transformed elliptic curve. """ coord_model = AffineCoordinateModel(self.model) - return EllipticCurve(self.model, coord_model, self.prime, self.neutral.to_affine(), - self.parameters) # type: ignore[arg-type] + return EllipticCurve( + self.model, + coord_model, + self.prime, + self.neutral.to_affine(), + self.parameters, + ) # type: ignore[arg-type] def decode_point(self, encoded: bytes) -> Point: """ @@ -325,7 +342,9 @@ class EllipticCurve: raise ValueError("Encoded point has bad length") x = mod(int.from_bytes(data, "big"), self.prime) loc = {**self.parameters, "x": x} - rhs = eval(compile(self.model.ysquared, "", mode="eval"), loc) # eval is OK here, skipcq: PYL-W0123 + rhs = eval( + compile(self.model.ysquared, "", mode="eval"), loc + ) # eval is OK here, skipcq: PYL-W0123 if not rhs.is_residue(): raise ValueError("Point not on curve") sqrt = rhs.sqrt() @@ -350,19 +369,25 @@ class EllipticCurve: :return: Lifted (affine) points, if any. """ loc = {**self.parameters, "x": x} - ysquared = eval(compile(self.model.ysquared, "", mode="eval"), loc) # eval is OK here, skipcq: PYL-W0123 + ysquared = eval( + compile(self.model.ysquared, "", mode="eval"), loc + ) # eval is OK here, skipcq: PYL-W0123 if not ysquared.is_residue(): return set() y = ysquared.sqrt() - return {Point(AffineCoordinateModel(self.model), x=x, y=y), - Point(AffineCoordinateModel(self.model), x=x, y=-y)} + return { + Point(AffineCoordinateModel(self.model), x=x, y=y), + Point(AffineCoordinateModel(self.model), x=x, y=-y), + } def affine_random(self) -> Point: """Generate a random affine point on the curve.""" while True: x = Mod.random(self.prime) loc = {**self.parameters, "x": x} - ysquared = eval(compile(self.model.ysquared, "", mode="eval"), loc) # eval is OK here, skipcq: PYL-W0123 + ysquared = eval( + compile(self.model.ysquared, "", mode="eval"), loc + ) # eval is OK here, skipcq: PYL-W0123 if ysquared.is_residue(): y = ysquared.sqrt() b = Mod.random(2) @@ -374,14 +399,22 @@ class EllipticCurve: if not isinstance(other, EllipticCurve): return False return ( - self.model == other.model - and self.coordinate_model == other.coordinate_model - and self.prime == other.prime - and self.parameters == other.parameters + self.model == other.model + and self.coordinate_model == other.coordinate_model + and self.prime == other.prime + and self.parameters == other.parameters ) def __hash__(self): - return hash((self.model, self.coordinate_model, self.prime, tuple(self.parameters.keys()), tuple(self.parameters.values()))) + return hash( + ( + self.model, + self.coordinate_model, + self.prime, + tuple(self.parameters.keys()), + tuple(self.parameters.values()), + ) + ) def __str__(self): return "EllipticCurve" |