From b6be57f42165d3b35b196ea09b55e206f4372951 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Wed, 20 Dec 2017 10:18:57 +0100
Subject: [PATCH] crypto: simplify check

---
 crypto/signature_nocgo.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crypto/signature_nocgo.go b/crypto/signature_nocgo.go
index 822208e9a3..f45a6202dc 100644
--- a/crypto/signature_nocgo.go
+++ b/crypto/signature_nocgo.go
@@ -87,7 +87,8 @@ func VerifySignature(pubkey, hash, signature []byte) bool {
 	if err != nil {
 		return false
 	}
-	if !ValidateSignatureValues(0, sig.R, sig.S, true) {
+	// Reject malleable signatures. libsecp256k1 does this check but btcec doesn't.
+	if s.Cmp(secp256k1_halfN) > 0 {
 		return false
 	}
 	return sig.Verify(hash, key)