From 8b9bf1bcbc963b432bcd44c781b60a7267007d96 Mon Sep 17 00:00:00 2001
From: J08nY
Date: Sat, 18 Oct 2025 21:21:27 +0200
Subject: Add point blinding countermeasure.

---
 test/ec/test_countermeasures.py | 30 +++++++++++++++++++++++++++++-
 test/sca/test_rpa.py            |  2 +-
 2 files changed, 30 insertions(+), 2 deletions(-)

(limited to 'test')

diff --git a/test/ec/test_countermeasures.py b/test/ec/test_countermeasures.py
index 946261c..c3a6ee3 100644
--- a/test/ec/test_countermeasures.py
+++ b/test/ec/test_countermeasures.py
@@ -9,6 +9,7 @@ from pyecsca.ec.countermeasures import (
     MultiplicativeSplitting,
     EuclideanSplitting,
     BrumleyTuveri,
+    PointBlinding,
 )
 from pyecsca.ec.mod import mod
 from pyecsca.ec.mult import *
@@ -246,6 +247,27 @@ def test_brumley_tuveri(mults, secp128r1, num):
         assert raw.equals(masked)
 
 
+@pytest.mark.parametrize(
+    "num",
+    [
+        3253857902090173296443513219124437746,
+        1234567893141592653589793238464338327,
+    ],
+)
+def test_point_blinding(mults, secp128r1, num):
+    mult = copy(mults[0])
+    mult.init(secp128r1, secp128r1.generator)
+    raw = mult.multiply(num)
+
+    neg = secp128r1.curve.coordinate_model.formulas["neg"]
+
+    for mult in mults:
+        pb = PointBlinding(mult, mult, neg=neg)
+        pb.init(secp128r1, secp128r1.generator)
+        masked = pb.multiply(num)
+        assert raw.equals(masked)
+
+
 @pytest.mark.parametrize(
     "scalar",
     [
@@ -264,6 +286,7 @@ def test_brumley_tuveri(mults, secp128r1, num):
             MultiplicativeSplitting,
             EuclideanSplitting,
             BrumleyTuveri,
+            PointBlinding,
         ),
         repeat=2,
     ),
@@ -279,15 +302,20 @@ def test_combination(scalar, one, two, secp128r1):
     mult.init(secp128r1, secp128r1.generator)
     raw = mult.multiply(scalar)
 
-    add = mult.formulas["add"]
+    add = secp128r1.curve.coordinate_model.formulas["add-2015-rcb"]
+    neg = secp128r1.curve.coordinate_model.formulas["neg"]
 
     if one in (AdditiveSplitting, EuclideanSplitting):
         layer_one = one.from_single(mult, add=add)
+    elif one == PointBlinding:
+        layer_one = one.from_single(mult, neg=neg)
     else:
         layer_one = one.from_single(mult)
 
     if two in (AdditiveSplitting, EuclideanSplitting):
         kws = {"add": add}
+    elif two == PointBlinding:
+        kws = {"neg": neg}
     else:
         kws = {}
 
diff --git a/test/sca/test_rpa.py b/test/sca/test_rpa.py
index 01293af..e92ec44 100644
--- a/test/sca/test_rpa.py
+++ b/test/sca/test_rpa.py
@@ -153,7 +153,7 @@ def test_multiples_kind(rpa_params):
 
 
 def test_multiples_additive(rpa_params):
-    mults = multiples_computed(1454656138887897564, rpa_params, LTRMultiplier, lambda *args, **kwargs: AdditiveSplitting(LTRMultiplier(*args, **kwargs)), True, True, kind="precomp+necessary")
+    mults = multiples_computed(1454656138887897564, rpa_params, LTRMultiplier, lambda *args, **kwargs: AdditiveSplitting.from_single(LTRMultiplier(*args, **kwargs)), True, True, kind="precomp+necessary")
     assert mults is not None
 
 
-- 
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