X-Git-Url: https://www.bearssl.org/gitweb//home/git/?p=BearSSL;a=blobdiff_plain;f=src%2Fec%2Fec_prime_i15.c;h=f86dbe6ff0dbc036af470e369048c4ae02d33337;hp=04bdd5da977d31935384817d3ae420d48d3d76d7;hb=dda1f8a0c46e15b4a235163470ff700b2f13dcc5;hpb=28e4e120b84dacdf53963639f1a8a6fec2793662

diff --git a/src/ec/ec_prime_i15.c b/src/ec/ec_prime_i15.c
index 04bdd5d..f86dbe6 100644
--- a/src/ec/ec_prime_i15.c
+++ b/src/ec/ec_prime_i15.c
@@ -716,6 +716,14 @@ api_order(int curve, size_t *len)
 	return cd->order;
 }
 
+static size_t
+api_xoff(int curve, size_t *len)
+{
+	api_generator(curve, len);
+	*len >>= 1;
+	return 1;
+}
+
 static uint32_t
 api_mul(unsigned char *G, size_t Glen,
 	const unsigned char *x, size_t xlen, int curve)
@@ -725,14 +733,28 @@ api_mul(unsigned char *G, size_t Glen,
 	jacobian P;
 
 	cc = id_to_curve(curve);
+	if (Glen != cc->point_len) {
+		return 0;
+	}
 	r = point_decode(&P, G, Glen, cc);
 	point_mul(&P, x, xlen, cc);
-	if (Glen == cc->point_len) {
-		point_encode(G, &P, cc);
-	}
+	point_encode(G, &P, cc);
 	return r;
 }
 
+static size_t
+api_mulgen(unsigned char *R,
+	const unsigned char *x, size_t xlen, int curve)
+{
+	const unsigned char *G;
+	size_t Glen;
+
+	G = api_generator(curve, &Glen);
+	memcpy(R, G, Glen);
+	api_mul(R, Glen, x, xlen, curve);
+	return Glen;
+}
+
 static uint32_t
 api_muladd(unsigned char *A, const unsigned char *B, size_t len,
 	const unsigned char *x, size_t xlen,
@@ -744,12 +766,20 @@ api_muladd(unsigned char *A, const unsigned char *B, size_t len,
 
 	/*
 	 * TODO: see about merging the two ladders. Right now, we do
-	 * two independant point multiplications, which is a bit
+	 * two independent point multiplications, which is a bit
 	 * wasteful of CPU resources (but yields short code).
 	 */
 
 	cc = id_to_curve(curve);
+	if (len != cc->point_len) {
+		return 0;
+	}
 	r = point_decode(&P, A, len, cc);
+	if (B == NULL) {
+		size_t Glen;
+
+		B = api_generator(curve, &Glen);
+	}
 	r &= point_decode(&Q, B, len, cc);
 	point_mul(&P, x, xlen, cc);
 	point_mul(&Q, y, ylen, cc);
@@ -787,6 +817,8 @@ const br_ec_impl br_ec_prime_i15 = {
 	(uint32_t)0x03800000,
 	&api_generator,
 	&api_order,
+	&api_xoff,
 	&api_mul,
+	&api_mulgen,
 	&api_muladd
 };