diff options
Diffstat (limited to 'pyecsca/ec/mult.py')
| -rw-r--r-- | pyecsca/ec/mult.py | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/pyecsca/ec/mult.py b/pyecsca/ec/mult.py index 7a8e23e..5804eef 100644 --- a/pyecsca/ec/mult.py +++ b/pyecsca/ec/mult.py @@ -27,6 +27,7 @@ class ScalarMultiplicationAction(ResultAction): return f"{self.__class__.__name__}({self.point}, {self.scalar})" +@public class ScalarMultiplier(ABC): """ A scalar multiplication algorithm. @@ -36,7 +37,9 @@ class ScalarMultiplier(ABC): :param formulas: Formulas this instance will use. """ requires: ClassVar[Set[Type]] # Type[Formula] but mypy has a false positive + """The set of formulas that the multiplier requires.""" optionals: ClassVar[Set[Type]] # Type[Formula] but mypy has a false positive + """The optional set of formulas that the multiplier can use.""" short_circuit: bool formulas: Mapping[str, Formula] _params: DomainParameters @@ -99,7 +102,15 @@ class ScalarMultiplier(ABC): return self.formulas["neg"](point, **self._params.curve.parameters)[0] def init(self, params: DomainParameters, point: Point): - """Initialize the scalar multiplier with params and a point.""" + """ + Initialize the scalar multiplier with params and a point. + + .. warning:: + The point is not verified to be on the curve represented in the domain parameters. + + :param params: The domain parameters to initialize the multiplier with. + :param point: The point to initialize the multiplier with. + """ coord_model = set(self.formulas.values()).pop().coordinate_model if params.curve.coordinate_model != coord_model or point.coordinate_model != coord_model: raise ValueError @@ -109,14 +120,22 @@ class ScalarMultiplier(ABC): @abstractmethod def multiply(self, scalar: int) -> Point: - """Multiply the point with the scalar.""" + """ + Multiply the point with the scalar. + + .. note:: + The multiplier needs to be initialized by a call to the :py:meth:`.init` method. + + :param scalar: The scalar to use. + :return: The resulting multiple. + """ ... @public class LTRMultiplier(ScalarMultiplier): """ - Classic double and add scalar multiplication algorithm, that scans the scalar left-to-right (msb to lsb) + Classic double and add scalar multiplication algorithm, that scans the scalar left-to-right (msb to lsb). The `always` parameter determines whether the double and add always method is used. """ @@ -161,7 +180,7 @@ class LTRMultiplier(ScalarMultiplier): @public class RTLMultiplier(ScalarMultiplier): """ - Classic double and add scalar multiplication algorithm, that scans the scalar right-to-left (lsb to msb) + Classic double and add scalar multiplication algorithm, that scans the scalar right-to-left (lsb to msb). The `always` parameter determines whether the double and add always method is used. """ @@ -195,6 +214,7 @@ class RTLMultiplier(ScalarMultiplier): return action.exit(r) +@public class CoronMultiplier(ScalarMultiplier): """ Coron's double and add resistant against SPA, from: @@ -407,7 +427,7 @@ class WindowNAFMultiplier(ScalarMultiplier): self._points_neg = {} current_point = point double_point = self._dbl(point) - for i in range(0, 2**(self.width - 2)): + for i in range(0, 2 ** (self.width - 2)): self._points[2 * i + 1] = current_point if self.precompute_negation: self._points_neg[2 * i + 1] = self._neg(current_point) |