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from public import public
from typing import MutableMapping, Union
from .coordinates import CoordinateModel
from .mod import Mod
from .model import CurveModel
from .point import Point
@public
class EllipticCurve(object):
model: CurveModel
coordinate_model: CoordinateModel
prime: int
parameters: MutableMapping[str, Mod]
neutral: Point
def __init__(self, model: CurveModel, coordinate_model: CoordinateModel,
prime: int, parameters: MutableMapping[str, Union[Mod, int]], neutral: Point):
# TODO: Add base_point arg, order arg, cofactor arg.
if coordinate_model not in model.coordinates.values():
raise ValueError
if set(model.parameter_names).symmetric_difference(parameters.keys()):
raise ValueError
if neutral.coordinate_model != coordinate_model:
raise ValueError
self.model = model
self.coordinate_model = coordinate_model
self.prime = prime
self.parameters = {}
for name, value in parameters.items():
if isinstance(value, Mod):
if value.n != prime:
raise ValueError
else:
value = Mod(value, prime)
self.parameters[name] = value
self.neutral = neutral
def is_on_curve(self, point: Point) -> bool:
if point.coordinate_model != self.coordinate_model:
return False
loc = {**self.parameters, **point.to_affine().coords}
return eval(compile(self.model.equation, "", mode="eval"), loc)
def is_neutral(self, point: Point) -> bool:
return self.neutral == point
def __repr__(self):
params = ", ".join((f"{key}={val}" for key, val in self.parameters.items()))
return f"EllipticCurve([{params}] on {self.model} using {self.coordinate_model})"
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