Handle always in Binary NAF mult.

1 files changed, 50 insertions, 10 deletions

diff --git a/pyecsca/codegen/templates/mult_bnaf.c b/pyecsca/codegen/templates/mult_bnaf.c
index 68d1569..d0cafdf 100644
--- a/pyecsca/codegen/templates/mult_bnaf.c
+++ b/pyecsca/codegen/templates/mult_bnaf.c
@@ -2,35 +2,73 @@
 #include "point.h"
 
 point_t *scalar_mult_ltr(point_t *point, point_t *neg, curve_t *curve, wnaf_t *naf) {
+    {% if scalarmult.always %}
+        point_t *q_copy = point_new();
+        point_t *dummy = point_new();
+    {% endif %}
+
     point_t *q = point_copy(curve->neutral);
 	for (long i = naf->length - 1; i >= 0; i--) {
 		point_dbl(q, curve, q);
+		{% if scalarmult.always %}
+            point_set(q, q_copy);
+        {% endif %}
+
 		if (naf->data[i] == 1) {
 			point_accumulate(q, point, curve, q);
+			{% if scalarmult.always %}
+                point_accumulate(q_copy, neg, curve, dummy);
+            {% endif %}
 		} else if (naf->data[i] == -1) {
 			point_accumulate(q, neg, curve, q);
+			{% if scalarmult.always %}
+                point_accumulate(q_copy, point, curve, dummy);
+            {% endif %}
 		}
 	}
+	{% if scalarmult.always %}
+        point_free(q_copy);
+        point_free(dummy);
+    {% endif %}
     return q;
 }
 
 point_t* scalar_mult_rtl(point_t *point, point_t *neg, curve_t *curve, wnaf_t *naf) {
-    point_t *r = point_copy(point);
-    point_t *q = point_copy(curve->neutral);
-    point_t *r_neg = point_new();
+    {% if scalarmult.always %}
+        point_t *r_copy = point_new();
+        point_t *dummy = point_new();
+    {% endif %}
+
+    point_t *q = point_copy(point);
+    point_t *r = point_copy(curve->neutral);
+    point_t *q_neg = point_new();
     for (long i = 0; i < naf->length; i++) {
+        {% if scalarmult.always %}
+            point_set(r, r_copy);
+        {% endif %}
         if (naf->data[i] == 1) {
-            point_accumulate(q, r, curve, q);
+            point_accumulate(r, q, curve, r);
+            {% if scalarmult.always %}
+                point_neg(q, curve, q_neg);
+                point_accumulate(r_copy, q_neg, curve, dummy);
+            {% endif %}
         } else if (naf->data[i] == -1) {
-            point_neg(r, curve, r_neg);
-            point_accumulate(q, r_neg, curve, q);
+            point_neg(q, curve, q_neg);
+            point_accumulate(r, q_neg, curve, r);
+            {% if scalarmult.always %}
+                point_accumulate(r_copy, q, curve, dummy);
+            {% endif %}
         }
-        point_dbl(r, curve, r);
+        point_dbl(q, curve, q);
     }
-    point_free(r_neg);
-    point_free(r);
+    point_free(q_neg);
+    point_free(q);
 
-    return q;
+    {% if scalarmult.always %}
+        point_free(r_copy);
+        point_free(dummy);
+    {% endif %}
+    return r;
 }
 
 static void scalar_mult_inner(bn_t *scalar, point_t *point, curve_t *curve, point_t *out) {
@@ -38,6 +76,8 @@ static void scalar_mult_inner(bn_t *scalar, point_t *point, curve_t *curve, poin
 	point_neg(point, curve, neg);
 	wnaf_t *naf = bn_bnaf(scalar);
 
+	{# TODO: Handle the ".complete" option #}
+
     {% if scalarmult.direction == ProcessingDirection.LTR %}
         point_t *q = scalar_mult_ltr(point, neg, curve, naf);
     {% elif scalarmult.direction == ProcessingDirection.RTL %}