diff options
Diffstat (limited to 'pyecsca/ec')
| -rw-r--r-- | pyecsca/ec/countermeasures.py | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/pyecsca/ec/countermeasures.py b/pyecsca/ec/countermeasures.py index ee07c2b..d6af799 100644 --- a/pyecsca/ec/countermeasures.py +++ b/pyecsca/ec/countermeasures.py @@ -20,9 +20,10 @@ class ScalarMultiplierCountermeasure(ABC): This class behaves like a scalar multiplier, in fact it wraps one and provides some scalar-splitting countermeasure. """ + mult: ScalarMultiplier params: Optional[DomainParameters] - point: Optional[Point] + point: Optional[Point] def __init__(self, mult: ScalarMultiplier): self.mult = mult @@ -45,12 +46,15 @@ class GroupScalarRandomization(ScalarMultiplierCountermeasure): self.rand_bits = rand_bits def multiply(self, scalar: int) -> Point: + if self.params is None or self.point is None: + raise ValueError("Not initialized.") self.mult.init(self.params, self.point) order = self.params.order mask = int(Mod.random(1 << self.rand_bits)) masked_scalar = scalar + mask * order return self.mult.multiply(masked_scalar) + @public class AdditiveSplitting(ScalarMultiplierCountermeasure): add: Optional[AdditionFormula] @@ -60,6 +64,8 @@ class AdditiveSplitting(ScalarMultiplierCountermeasure): self.add = add def multiply(self, scalar: int) -> Point: + if self.params is None or self.point is None: + raise ValueError("Not initialized.") self.mult.init(self.params, self.point) order = self.params.order @@ -70,7 +76,9 @@ class AdditiveSplitting(ScalarMultiplierCountermeasure): if self.add is None: return self.mult._add(R, S) # noqa: This is OK. else: - return self.add(self.params.curve.prime, R, S, **self.params.curve.parameters)[0] + return self.add( + self.params.curve.prime, R, S, **self.params.curve.parameters + )[0] @public @@ -82,6 +90,8 @@ class MultiplicativeSplitting(ScalarMultiplierCountermeasure): self.rand_bits = rand_bits def multiply(self, scalar: int) -> Point: + if self.params is None or self.point is None: + raise ValueError("Not initialized.") self.mult.init(self.params, self.point) r = Mod.random(1 << self.rand_bits) R = self.mult.multiply(int(r)) @@ -90,6 +100,7 @@ class MultiplicativeSplitting(ScalarMultiplierCountermeasure): kr_inv = scalar * mod(int(r), self.params.order).inverse() return self.mult.multiply(int(kr_inv)) + @public class EuclideanSplitting(ScalarMultiplierCountermeasure): add: Optional[AdditionFormula] @@ -99,6 +110,8 @@ class EuclideanSplitting(ScalarMultiplierCountermeasure): self.add = add def multiply(self, scalar: int) -> Point: + if self.params is None or self.point is None: + raise ValueError("Not initialized.") order = self.params.order half_bits = order.bit_length() // 2 r = Mod.random(1 << half_bits) @@ -115,4 +128,6 @@ class EuclideanSplitting(ScalarMultiplierCountermeasure): if self.add is None: return self.mult._add(S, T) # noqa: This is OK. else: - return self.add(self.params.curve.prime, S, T, **self.params.curve.parameters)[0]
\ No newline at end of file + return self.add( + self.params.curve.prime, S, T, **self.params.curve.parameters + )[0] |