diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
index 51ab55ebc..a684eb5a9 100644
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -22,6 +22,7 @@
 ### IMPROVEMENTS
 
 - [pubsub] \#7319 Performance improvements for the event query API (@creachadair)
+- [crypto/merkle] \#6443 Improve HashAlternatives performance (@cuonglm)
 
 ### BUG FIXES
 
diff --git a/crypto/merkle/hash.go b/crypto/merkle/hash.go
index d45130fe5..f35efbd2f 100644
--- a/crypto/merkle/hash.go
+++ b/crypto/merkle/hash.go
@@ -22,5 +22,9 @@ func leafHash(leaf []byte) []byte {
 
 // returns tmhash(0x01 || left || right)
 func innerHash(left []byte, right []byte) []byte {
-	return tmhash.Sum(append(innerPrefix, append(left, right...)...))
+	data := make([]byte, len(innerPrefix)+len(left)+len(right))
+	n := copy(data, innerPrefix)
+	n += copy(data[n:], left)
+	copy(data[n:], right)
+	return tmhash.Sum(data)
 }