diff --git a/hdkeychain/extendedkey.go b/hdkeychain/extendedkey.go
index 48c0421..89727ac 100644
--- a/hdkeychain/extendedkey.go
+++ b/hdkeychain/extendedkey.go
@@ -198,14 +198,6 @@ func (k *ExtendedKey) ChainCode() []byte {
 	return append([]byte{}, k.chainCode...)
 }
 
-// ChildNum returns the index at which the child extended key was derived.
-//
-// Extended keys with ChildNum value between 0 and 2^31-1 are normal child
-// keys, and those with a value between 2^31 and 2^32-1 are hardened keys.
-func (k *ExtendedKey) ChildNum() uint32 {
-	return k.childNum
-}
-
 // Child returns a derived child extended key at the given index.  When this
 // extended key is a private extended key (as determined by the IsPrivate
 // function), a private extended key will be derived.  Otherwise, the derived
@@ -350,7 +342,10 @@ func (k *ExtendedKey) Child(i uint32) (*ExtendedKey, error) {
 		k.depth+1, i, isPrivate), nil
 }
 
-// ChildIndex returns the child index used to derive the extended key.
+// ChildNum returns the index at which the child extended key was derived.
+//
+// Extended keys with ChildNum value between 0 and 2^31-1 are normal child
+// keys, and those with a value between 2^31 and 2^32-1 are hardened keys.
 func (k *ExtendedKey) ChildIndex() uint32 {
 	return k.childNum
 }
diff --git a/hdkeychain/extendedkey_test.go b/hdkeychain/extendedkey_test.go
index 09c6f05..04c6673 100644
--- a/hdkeychain/extendedkey_test.go
+++ b/hdkeychain/extendedkey_test.go
@@ -623,10 +623,10 @@ func TestExtendedKeyAPI(t *testing.T) {
 			continue
 		}
 
-		childNum := key.ChildNum()
-		if childNum != test.childNum {
-			t.Errorf("ChildNum #%d (%s): want %d, got %d", i,
-				test.name, childNum, test.childNum)
+		childIndex := key.ChildIndex()
+		if childIndex != test.childNum {
+			t.Errorf("ChildIndex #%d (%s): want %d, got %d", i,
+				test.name, test.childNum, childIndex)
 			continue
 		}