diff --git a/trie/database.go b/trie/database.go
index 4f984b010a..6d7a160654 100644
--- a/trie/database.go
+++ b/trie/database.go
@@ -233,7 +233,7 @@ func expandNode(hash hashNode, n node) node {
 		return &shortNode{
 			Key: compactToHex(n.Key),
 			Val: expandNode(nil, n.Val),
-			flags: NodeFlag{
+			flags: nodeFlag{
 				hash: hash,
 			},
 		}
@@ -241,7 +241,7 @@ func expandNode(hash hashNode, n node) node {
 	case rawFullNode:
 		// Full nodes need child expansion
 		node := &fullNode{
-			flags: NodeFlag{
+			flags: nodeFlag{
 				hash: hash,
 			},
 		}
diff --git a/trie/node.go b/trie/node.go
index 2aa1dc3bfe..45184524c0 100644
--- a/trie/node.go
+++ b/trie/node.go
@@ -36,12 +36,12 @@ type node interface {
 type (
 	fullNode struct {
 		Children [17]node // Actual trie Node data to encode/decode (needs custom encoder)
-		flags    NodeFlag
+		flags    nodeFlag
 	}
 	shortNode struct {
 		Key   []byte
 		Val   node
-		flags NodeFlag
+		flags nodeFlag
 	}
 	hashNode  []byte
 	valueNode []byte
@@ -61,8 +61,8 @@ func (n *fullNode) EncodeRLP(w io.Writer) error {
 func (n *fullNode) copy() *fullNode   { copy := *n; return &copy }
 func (n *shortNode) copy() *shortNode { copy := *n; return &copy }
 
-// NodeFlag contains caching-related metadata about a Node.
-type NodeFlag struct {
+// nodeFlag contains caching-related metadata about a Node.
+type nodeFlag struct {
 	hash  hashNode // cached hash of the Node (may be nil)
 	dirty bool     // whether the Node has changes that must be written to the database
 }
@@ -133,7 +133,7 @@ func decodeShort(hash, elems []byte) (node, error) {
 	if err != nil {
 		return nil, err
 	}
-	flag := NodeFlag{hash: hash}
+	flag := nodeFlag{hash: hash}
 	key := compactToHex(kbuf)
 	if hasTerm(key) {
 		// value Node
@@ -151,7 +151,7 @@ func decodeShort(hash, elems []byte) (node, error) {
 }
 
 func decodeFull(hash, elems []byte) (*fullNode, error) {
-	n := &fullNode{flags: NodeFlag{hash: hash}}
+	n := &fullNode{flags: nodeFlag{hash: hash}}
 	for i := 0; i < 16; i++ {
 		cld, rest, err := decodeRef(elems)
 		if err != nil {
diff --git a/trie/proof.go b/trie/proof.go
index 28139bebf2..a12886cb35 100644
--- a/trie/proof.go
+++ b/trie/proof.go
@@ -236,7 +236,7 @@ findFork:
 			if len(right)-pos < len(rn.Key) || !bytes.Equal(rn.Key, right[pos:pos+len(rn.Key)]) {
 				return errors.New("invalid edge path")
 			}
-			rn.flags = NodeFlag{dirty: true}
+			rn.flags = nodeFlag{dirty: true}
 			// Special case, the non-existent proof points to the same path
 			// as the existent proof, but the path of existent proof is longer.
 			// In this case, the fork point is this shortnode.
@@ -251,7 +251,7 @@ findFork:
 			if rightnode == nil {
 				return errors.New("invalid edge path")
 			}
-			rn.flags = NodeFlag{dirty: true}
+			rn.flags = nodeFlag{dirty: true}
 			if leftnode != rightnode {
 				break findFork
 			}
@@ -305,12 +305,12 @@ func unset(parent node, child node, key []byte, pos int, removeLeft bool) error
 			for i := 0; i < int(key[pos]); i++ {
 				cld.Children[i] = nil
 			}
-			cld.flags = NodeFlag{dirty: true}
+			cld.flags = nodeFlag{dirty: true}
 		} else {
 			for i := key[pos] + 1; i < 16; i++ {
 				cld.Children[i] = nil
 			}
-			cld.flags = NodeFlag{dirty: true}
+			cld.flags = nodeFlag{dirty: true}
 		}
 		return unset(cld, cld.Children[key[pos]], key, pos+1, removeLeft)
 	case *shortNode:
@@ -337,7 +337,7 @@ func unset(parent node, child node, key []byte, pos int, removeLeft bool) error
 			fn.Children[key[pos-1]] = nil
 			return nil
 		}
-		cld.flags = NodeFlag{dirty: true}
+		cld.flags = nodeFlag{dirty: true}
 		return unset(cld, cld.Val, key, pos+len(cld.Key), removeLeft)
 	case nil:
 		// If the Node is nil, it's a child of the fork point
diff --git a/trie/trie.go b/trie/trie.go
index 695b38c70d..ad5804e0f9 100644
--- a/trie/trie.go
+++ b/trie/trie.go
@@ -47,8 +47,8 @@ type Trie struct {
 }
 
 // newFlag returns the Cache flag value for a newly created Node.
-func (t *Trie) newFlag() NodeFlag {
-	return NodeFlag{dirty: true}
+func (t *Trie) newFlag() nodeFlag {
+	return nodeFlag{dirty: true}
 }
 
 // New creates a trie with an existing root Node from Db.