2 files changed, 39 insertions, 6 deletions

diff --git a/pyecsca/ec/divpoly.py b/pyecsca/ec/divpoly.py
index 460b861..c92ef64 100644
--- a/pyecsca/ec/divpoly.py
+++ b/pyecsca/ec/divpoly.py
@@ -1,3 +1,6 @@
+"""
+Provides functions for computing division polynomials and the multiplication-by-n map on an elliptic curve.
+"""
 from typing import Tuple, Dict, Set, Mapping
 
 from sympy import symbols, FF, Poly
@@ -167,10 +170,10 @@ def divpoly(curve: EllipticCurve, n: int, two_torsion_multiplicity: int = 2) ->
     """
     Compute the n-th division polynomial.
 
-    :param curve:
-    :param n:
-    :param two_torsion_multiplicity:
-    :return:
+    :param curve: Curve to compute on.
+    :param n: Scalar.
+    :param two_torsion_multiplicity: Same as sagemath.
+    :return: The division polynomial.
     """
     f: Poly = divpoly0(curve, n)[n]
     a1, a2, a3, a4, a6 = a_invariants(curve)
@@ -199,7 +202,7 @@ def mult_by_n(curve: EllipticCurve, n: int) -> Tuple[Tuple[Poly, Poly], Tuple[Po
 
     :param curve: Curve to compute on.
     :param n: Scalar.
-    :return:
+    :return: A tuple (mx, my) where each is a tuple (numerator, denominator).
     """
     xs, ys = symbols("x y")
     K = FF(curve.prime)
@@ -208,7 +211,7 @@ def mult_by_n(curve: EllipticCurve, n: int) -> Tuple[Tuple[Poly, Poly], Tuple[Po
     Kxy = lambda r: Poly(r, xs, ys, domain=K)  # noqa
 
     if n == 1:
-        return x
+        return x, y
 
     a1, a2, a3, a4, a6 = a_invariants(curve)
 
diff --git a/test/ec/perf_divpoly.py b/test/ec/perf_divpoly.py
new file mode 100755
index 0000000..2937af1
--- /dev/null
+++ b/test/ec/perf_divpoly.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+import click
+
+from pyecsca.ec.divpoly import mult_by_n
+from pyecsca.ec.params import get_params
+from datetime import datetime
+
+
+@click.command()
+@click.option("-n", type=click.INT, default=21)
+def main(n):
+    p256 = get_params("secg", "secp256r1", "projective")
+
+    ns = []
+    durs = []
+    mems = []
+    for i in range(2, n):
+        start = datetime.now()
+        mx, my = mult_by_n(p256.curve, i)
+        end = datetime.now()
+        duration = (end - start).total_seconds()
+        memory = (mx[0].degree() + mx[1].degree() + my[0].degree() + my[1].degree()) * 32
+        ns.append(i)
+        durs.append((end - start).total_seconds())
+        mems.append(memory)
+        print(i, duration, memory, sep=",")
+
+
+if __name__ == "__main__":
+    main()