diff --git a/core/state/iterator.go b/core/state/iterator.go
index 29c4abfc2..79bb650ab 100644
--- a/core/state/iterator.go
+++ b/core/state/iterator.go
@@ -26,9 +26,9 @@ import (
 	"github.com/ethereum/go-ethereum/trie"
 )
 
-// NodeIterator is an iterator to traverse the entire state trie post-order,
+// nodeIterator is an iterator to traverse the entire state trie post-order,
 // including all of the contract code and contract state tries.
-type NodeIterator struct {
+type nodeIterator struct {
 	state *StateDB // State being iterated
 
 	stateIt trie.NodeIterator // Primary iterator for the global state trie
@@ -44,9 +44,9 @@ type NodeIterator struct {
 	Error error // Failure set in case of an internal error in the iterator
 }
 
-// NewNodeIterator creates an post-order state node iterator.
-func NewNodeIterator(state *StateDB) *NodeIterator {
-	return &NodeIterator{
+// newNodeIterator creates an post-order state node iterator.
+func newNodeIterator(state *StateDB) *nodeIterator {
+	return &nodeIterator{
 		state: state,
 	}
 }
@@ -54,7 +54,7 @@ func NewNodeIterator(state *StateDB) *NodeIterator {
 // Next moves the iterator to the next node, returning whether there are any
 // further nodes. In case of an internal error this method returns false and
 // sets the Error field to the encountered failure.
-func (it *NodeIterator) Next() bool {
+func (it *nodeIterator) Next() bool {
 	// If the iterator failed previously, don't do anything
 	if it.Error != nil {
 		return false
@@ -68,7 +68,7 @@ func (it *NodeIterator) Next() bool {
 }
 
 // step moves the iterator to the next entry of the state trie.
-func (it *NodeIterator) step() error {
+func (it *nodeIterator) step() error {
 	// Abort if we reached the end of the iteration
 	if it.state == nil {
 		return nil
@@ -131,7 +131,7 @@ func (it *NodeIterator) step() error {
 
 // retrieve pulls and caches the current state entry the iterator is traversing.
 // The method returns whether there are any more data left for inspection.
-func (it *NodeIterator) retrieve() bool {
+func (it *nodeIterator) retrieve() bool {
 	// Clear out any previously set values
 	it.Hash = common.Hash{}
 
diff --git a/core/state/iterator_test.go b/core/state/iterator_test.go
index 24b192c26..c8e1a181e 100644
--- a/core/state/iterator_test.go
+++ b/core/state/iterator_test.go
@@ -36,7 +36,7 @@ func TestNodeIteratorCoverage(t *testing.T) {
 	}
 	// Gather all the node hashes found by the iterator
 	hashes := make(map[common.Hash]struct{})
-	for it := NewNodeIterator(state); it.Next(); {
+	for it := newNodeIterator(state); it.Next(); {
 		if it.Hash != (common.Hash{}) {
 			hashes[it.Hash] = struct{}{}
 		}
diff --git a/core/state/sync_test.go b/core/state/sync_test.go
index 87621f49c..8f8430559 100644
--- a/core/state/sync_test.go
+++ b/core/state/sync_test.go
@@ -125,7 +125,7 @@ func checkStateConsistency(db ethdb.Database, root common.Hash) error {
 	if err != nil {
 		return err
 	}
-	it := NewNodeIterator(state)
+	it := newNodeIterator(state)
 	for it.Next() {
 	}
 	return it.Error