1 files changed, 29 insertions, 2 deletions
diff --git a/pyecsca/ec/curve.py b/pyecsca/ec/curve.py
index b161f7b..b9a4770 100644
--- a/pyecsca/ec/curve.py
+++ b/pyecsca/ec/curve.py
@@ -1,8 +1,9 @@
-from typing import MutableMapping, Union
+from ast import Module
+from typing import MutableMapping, Union, List
 
 from public import public
 
-from .coordinates import CoordinateModel
+from .coordinates import CoordinateModel, AffineCoordinateModel
 from .mod import Mod
 from .model import CurveModel
 from .point import Point
@@ -33,6 +34,32 @@ class EllipticCurve(object):
                 value = Mod(value, prime)
             self.parameters[name] = value
 
+    def _execute_base_formulas(self, formulas: List[Module], *points: Point) -> Point:
+        for point in points:
+            if point.coordinate_model.curve_model != self.model:
+                raise ValueError
+            if not isinstance(point.coordinate_model, AffineCoordinateModel):
+                raise ValueError
+        locals = {var + str(i + 1): point.coords[var]
+                  for i, point in enumerate(points) for var in point.coords}
+        locals.update(self.parameters)
+        for line in formulas:
+            exec(compile(line, "", mode="exec"), None, locals)
+        return Point(AffineCoordinateModel(self), x=locals["x"], y=locals["y"])
+
+    def affine_add(self, one: Point, other: Point) -> Point:
+        return self._execute_base_formulas(self.model.base_addition, one, other)
+
+    def affine_double(self, one: Point) -> Point:
+        return self._execute_base_formulas(self.model.base_doubling, one)
+
+    def affine_negate(self, one: Point) -> Point:
+        return self._execute_base_formulas(self.model.base_negation, one)
+
+    @property
+    def neutral_is_affine(self):
+        return bool(self.model.base_neutral)
+
     def is_on_curve(self, point: Point) -> bool:
         if point.coordinate_model.curve_model != self.model:
             return False