From dc34e17797ba5c57c0da679bcae8ee2e9a89c3d0 Mon Sep 17 00:00:00 2001
From: Emman <emman.sun@cargosmart.com>
Date: Fri, 8 Apr 2022 11:18:45 +0800
Subject: [PATCH] tolerate zero-padded scalars in generic implementation

---
 sm2/p256.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sm2/p256.go b/sm2/p256.go
index 27b0d83..5c07017 100644
--- a/sm2/p256.go
+++ b/sm2/p256.go
@@ -57,7 +57,7 @@ func p256GetScalar(out *[32]byte, in []byte) {
 	n := new(big.Int).SetBytes(in)
 	var scalarBytes []byte
 
-	if n.Cmp(p256.N) >= 0 {
+	if n.Cmp(p256.N) >= 0 || len(in) > len(out) {
 		n.Mod(n, p256.N)
 		scalarBytes = n.Bytes()
 	} else {