From 63f222c60b03470c0005aa9bc4296fbf585f68b9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Niels=20M=C3=B6ller?= Date: Sat, 13 Mar 2021 16:45:34 +0100 Subject: [PATCH] Fix canonical reduction in gostdsa_vko. * gostdsa-vko.c (gostdsa_vko): Use ecc_mod_mul_canonical to compute the scalar used for ecc multiplication. (cherry picked from commit b30e0ca6d2b41579a5b6a010fc54065d790e8d55) --- ChangeLog | 3 +++ gostdsa-vko.c | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) #diff --git a/ChangeLog b/ChangeLog #index ce330831..8a27a9a6 100644 #--- a/ChangeLog #+++ b/ChangeLog #@@ -1,5 +1,8 @@ # 2021-03-13 Niels Möller # #+ * gostdsa-vko.c (gostdsa_vko): Use ecc_mod_mul_canonical to #+ compute the scalar used for ecc multiplication. #+ # * eddsa-hash.c (_eddsa_hash): Ensure result is canonically # reduced. Two of the three call sites need that. # --- a/gostdsa-vko.c +++ b/gostdsa-vko.c @@ -87,7 +87,7 @@ gostdsa_vko (const struct ecc_scalar *pr if (mpn_zero_p (UKM, size)) UKM[0] = 1; - ecc_mod_mul (&ecc->q, TEMP, priv->p, UKM); /* TEMP = UKM * priv */ + ecc_mod_mul_canonical (&ecc->q, TEMP, priv->p, UKM, TEMP); /* TEMP = UKM * priv */ ecc->mul (ecc, XYZ, TEMP, pub->p, scratch + 4*size); /* XYZ = UKM * priv * pub */ ecc->h_to_a (ecc, 0, TEMP, XYZ, scratch + 5*size); /* TEMP = XYZ */ mpn_get_base256_le (out, bsize, TEMP, size);