trie: remove redundant returns + use stacktrie where applicable #22760 (#1066)

* trie: add benchmark for proofless range

* trie: remove unused returns + use stacktrie

Co-authored-by: Martin Holst Swende <martin@swende.se>

trie/notary.go

@@ -21,17 +21,17 @@ import (
 	"github.com/XinFinOrg/XDPoSChain/ethdb/memorydb"
 )
 
-// KeyValueNotary tracks which keys have been accessed through a key-value reader
+// keyValueNotary tracks which keys have been accessed through a key-value reader
 // with te scope of verifying if certain proof datasets are maliciously bloated.
-type KeyValueNotary struct {
+type keyValueNotary struct {
 	ethdb.KeyValueReader
 	reads map[string]struct{}
 }
 
-// NewKeyValueNotary wraps a key-value database with an access notary to track
+// newKeyValueNotary wraps a key-value database with an access notary to track
 // which items have bene accessed.
-func NewKeyValueNotary(db ethdb.KeyValueReader) *KeyValueNotary {
+func newKeyValueNotary(db ethdb.KeyValueReader) *keyValueNotary {
-	return &KeyValueNotary{
+	return &keyValueNotary{
 		KeyValueReader: db,
 		reads:          make(map[string]struct{}),
 	}
@@ -39,14 +39,14 @@ func NewKeyValueNotary(db ethdb.KeyValueReader) *KeyValueNotary {
 
 // Get retrieves an item from the underlying database, but also tracks it as an
 // accessed slot for bloat checks.
-func (k *KeyValueNotary) Get(key []byte) ([]byte, error) {
+func (k *keyValueNotary) Get(key []byte) ([]byte, error) {
 	k.reads[string(key)] = struct{}{}
 	return k.KeyValueReader.Get(key)
 }
 
 // Accessed returns s snapshot of the original key-value store containing only the
 // data accessed through the notary.
-func (k *KeyValueNotary) Accessed() ethdb.KeyValueStore {
+func (k *keyValueNotary) Accessed() ethdb.KeyValueStore {
 	db := memorydb.New()
 	for keystr := range k.reads {
 		key := []byte(keystr)

trie/proof.go

@@ -463,115 +463,100 @@ func hasRightElement(node node, key []byte) bool {
 //
 // Except returning the error to indicate the proof is valid or not, the function will
 // also return a flag to indicate whether there exists more accounts/slots in the trie.
-func VerifyRangeProof(rootHash common.Hash, firstKey []byte, lastKey []byte, keys [][]byte, values [][]byte, proof ethdb.KeyValueReader) (ethdb.KeyValueStore, *Trie, *KeyValueNotary, bool, error) {
+func VerifyRangeProof(rootHash common.Hash, firstKey []byte, lastKey []byte, keys [][]byte, values [][]byte, proof ethdb.KeyValueReader) (ethdb.KeyValueStore, bool, error) {
 	if len(keys) != len(values) {
-		return nil, nil, nil, false, fmt.Errorf("inconsistent proof data, keys: %d, values: %d", len(keys), len(values))
+		return nil, false, fmt.Errorf("inconsistent proof data, keys: %d, values: %d", len(keys), len(values))
 	}
 	// Ensure the received batch is monotonic increasing.
 	for i := 0; i < len(keys)-1; i++ {
 		if bytes.Compare(keys[i], keys[i+1]) >= 0 {
-			return nil, nil, nil, false, errors.New("range is not monotonically increasing")
+			return nil, false, errors.New("range is not monotonically increasing")
 		}
 	}
 	// Create a key-value notary to track which items from the given proof the
 	// range prover actually needed to verify the data
-	notary := NewKeyValueNotary(proof)
+	notary := newKeyValueNotary(proof)
 
 	// Special case, there is no edge proof at all. The given range is expected
 	// to be the whole leaf-set in the trie.
 	if proof == nil {
 		var (
 			diskdb = memorydb.New()
-			triedb = NewDatabase(diskdb)
+			tr     = NewStackTrie(diskdb)
 		)
-		tr, err := New(common.Hash{}, triedb)
-		if err != nil {
-			return nil, nil, nil, false, err
-		}
 		for index, key := range keys {
 			tr.TryUpdate(key, values[index])
 		}
-		if tr.Hash() != rootHash {
+		if have, want := tr.Hash(), rootHash; have != want {
-			return nil, nil, nil, false, fmt.Errorf("invalid proof, want hash %x, got %x", rootHash, tr.Hash())
+			return nil, false, fmt.Errorf("invalid proof, want hash %x, got %x", want, have)
 		}
-		// Proof seems valid, serialize all the nodes into the database
+		// Proof seems valid, serialize remaining nodes into the database
-		if _, err := tr.Commit(nil); err != nil {
+		if _, err := tr.Commit(); err != nil {
-			return nil, nil, nil, false, err
+			return nil, false, err
 		}
-		if err := triedb.Commit(rootHash, false); err != nil {
+		return diskdb, false, nil // No more elements
-			return nil, nil, nil, false, err
-		}
-		return diskdb, tr, notary, false, nil // No more elements
 	}
 	// Special case, there is a provided edge proof but zero key/value
 	// pairs, ensure there are no more accounts / slots in the trie.
 	if len(keys) == 0 {
 		root, val, err := proofToPath(rootHash, nil, firstKey, notary, true)
 		if err != nil {
-			return nil, nil, nil, false, err
+			return nil, false, err
 		}
 		if val != nil || hasRightElement(root, firstKey) {
-			return nil, nil, nil, false, errors.New("more entries available")
+			return nil, false, errors.New("more entries available")
 		}
 		// Since the entire proof is a single path, we can construct a trie and a
 		// node database directly out of the inputs, no need to generate them
 		diskdb := notary.Accessed()
-		tr := &Trie{
+		return diskdb, hasRightElement(root, firstKey), nil
-			Db:   NewDatabase(diskdb),
-			root: root,
-		}
-		return diskdb, tr, notary, hasRightElement(root, firstKey), nil
 	}
 	// Special case, there is only one element and two edge keys are same.
 	// In this case, we can't construct two edge paths. So handle it here.
 	if len(keys) == 1 && bytes.Equal(firstKey, lastKey) {
 		root, val, err := proofToPath(rootHash, nil, firstKey, notary, false)
 		if err != nil {
-			return nil, nil, nil, false, err
+			return nil, false, err
 		}
 		if !bytes.Equal(firstKey, keys[0]) {
-			return nil, nil, nil, false, errors.New("correct proof but invalid key")
+			return nil, false, errors.New("correct proof but invalid key")
 		}
 		if !bytes.Equal(val, values[0]) {
-			return nil, nil, nil, false, errors.New("correct proof but invalid data")
+			return nil, false, errors.New("correct proof but invalid data")
 		}
 		// Since the entire proof is a single path, we can construct a trie and a
 		// node database directly out of the inputs, no need to generate them
 		diskdb := notary.Accessed()
-		tr := &Trie{
+		return diskdb, hasRightElement(root, firstKey), nil
-			Db:   NewDatabase(diskdb),
-			root: root,
-		}
-		return diskdb, tr, notary, hasRightElement(root, firstKey), nil
 	}
 	// Ok, in all other cases, we require two edge paths available.
 	// First check the validity of edge keys.
 	if bytes.Compare(firstKey, lastKey) >= 0 {
-		return nil, nil, nil, false, errors.New("invalid edge keys")
+		return nil, false, errors.New("invalid edge keys")
 	}
 	// todo(rjl493456442) different length edge keys should be supported
 	if len(firstKey) != len(lastKey) {
-		return nil, nil, nil, false, errors.New("inconsistent edge keys")
+		return nil, false, errors.New("inconsistent edge keys")
 	}
 	// Convert the edge proofs to edge trie paths. Then we can
 	// have the same tree architecture with the original one.
 	// For the first edge proof, non-existent proof is allowed.
 	root, _, err := proofToPath(rootHash, nil, firstKey, notary, true)
 	if err != nil {
-		return nil, nil, nil, false, err
+		return nil, false, err
 	}
 	// Pass the root node here, the second path will be merged
 	// with the first one. For the last edge proof, non-existent
 	// proof is also allowed.
 	root, _, err = proofToPath(rootHash, root, lastKey, notary, true)
 	if err != nil {
-		return nil, nil, nil, false, err
+		return nil, false, err
 	}
 	// Remove all internal references. All the removed parts should
 	// be re-filled(or re-constructed) by the given leaves range.
 	empty, err := unsetInternal(root, firstKey, lastKey)
 	if err != nil {
-		return nil, nil, nil, false, err
+		return nil, false, err
 	}
 	// Rebuild the trie with the leaf stream, the shape of trie
 	// should be same with the original one.
@@ -587,16 +572,16 @@ func VerifyRangeProof(rootHash common.Hash, firstKey []byte, lastKey []byte, key
 		tr.TryUpdate(key, values[index])
 	}
 	if tr.Hash() != rootHash {
-		return nil, nil, nil, false, fmt.Errorf("invalid proof, want hash %x, got %x", rootHash, tr.Hash())
+		return nil, false, fmt.Errorf("invalid proof, want hash %x, got %x", rootHash, tr.Hash())
 	}
 	// Proof seems valid, serialize all the nodes into the database
 	if _, err := tr.Commit(nil); err != nil {
-		return nil, nil, nil, false, err
+		return nil, false, err
 	}
 	if err := triedb.Commit(rootHash, false); err != nil {
-		return nil, nil, nil, false, err
+		return nil, false, err
 	}
-	return diskdb, tr, notary, hasRightElement(root, keys[len(keys)-1]), nil
+	return diskdb, hasRightElement(root, keys[len(keys)-1]), nil
 }
 
 // get returns the child of the given Node. Return nil if the

trie/proof_test.go

@@ -177,7 +177,7 @@ func TestRangeProof(t *testing.T) {
 			keys = append(keys, entries[i].k)
 			vals = append(vals, entries[i].v)
 		}
-		_, _, _, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof)
+		_, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof)
 		if err != nil {
 			t.Fatalf("Case %d(%d->%d) expect no error, got %v", i, start, end-1, err)
 		}
@@ -228,7 +228,7 @@ func TestRangeProofWithNonExistentProof(t *testing.T) {
 			keys = append(keys, entries[i].k)
 			vals = append(vals, entries[i].v)
 		}
-		_, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof)
+		_, _, err := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof)
 		if err != nil {
 			t.Fatalf("Case %d(%d->%d) expect no error, got %v", i, start, end-1, err)
 		}
@@ -249,7 +249,7 @@ func TestRangeProofWithNonExistentProof(t *testing.T) {
 		k = append(k, entries[i].k)
 		v = append(v, entries[i].v)
 	}
-	_, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, k, v, proof)
+	_, _, err := VerifyRangeProof(trie.Hash(), first, last, k, v, proof)
 	if err != nil {
 		t.Fatal("Failed to verify whole rang with non-existent edges")
 	}
@@ -284,7 +284,7 @@ func TestRangeProofWithInvalidNonExistentProof(t *testing.T) {
 		k = append(k, entries[i].k)
 		v = append(v, entries[i].v)
 	}
-	_, _, _, _, err := VerifyRangeProof(trie.Hash(), first, k[len(k)-1], k, v, proof)
+	_, _, err := VerifyRangeProof(trie.Hash(), first, k[len(k)-1], k, v, proof)
 	if err == nil {
 		t.Fatalf("Expected to detect the error, got nil")
 	}
@@ -306,7 +306,7 @@ func TestRangeProofWithInvalidNonExistentProof(t *testing.T) {
 		k = append(k, entries[i].k)
 		v = append(v, entries[i].v)
 	}
-	_, _, _, _, err = VerifyRangeProof(trie.Hash(), k[0], last, k, v, proof)
+	_, _, err = VerifyRangeProof(trie.Hash(), k[0], last, k, v, proof)
 	if err == nil {
 		t.Fatalf("Expected to detect the error, got nil")
 	}
@@ -330,7 +330,7 @@ func TestOneElementRangeProof(t *testing.T) {
 	if err := trie.Prove(entries[start].k, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the first node %v", err)
 	}
-	_, _, _, _, err := VerifyRangeProof(trie.Hash(), entries[start].k, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
+	_, _, err := VerifyRangeProof(trie.Hash(), entries[start].k, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -345,7 +345,7 @@ func TestOneElementRangeProof(t *testing.T) {
 	if err := trie.Prove(entries[start].k, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err = VerifyRangeProof(trie.Hash(), first, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
+	_, _, err = VerifyRangeProof(trie.Hash(), first, entries[start].k, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -360,7 +360,7 @@ func TestOneElementRangeProof(t *testing.T) {
 	if err := trie.Prove(last, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err = VerifyRangeProof(trie.Hash(), entries[start].k, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
+	_, _, err = VerifyRangeProof(trie.Hash(), entries[start].k, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -375,7 +375,7 @@ func TestOneElementRangeProof(t *testing.T) {
 	if err := trie.Prove(last, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
+	_, _, err = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[start].k}, [][]byte{entries[start].v}, proof)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -394,7 +394,7 @@ func TestOneElementRangeProof(t *testing.T) {
 	if err := tinyTrie.Prove(last, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err = VerifyRangeProof(tinyTrie.Hash(), first, last, [][]byte{entry.k}, [][]byte{entry.v}, proof)
+	_, _, err = VerifyRangeProof(tinyTrie.Hash(), first, last, [][]byte{entry.k}, [][]byte{entry.v}, proof)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -416,7 +416,7 @@ func TestAllElementsProof(t *testing.T) {
 		k = append(k, entries[i].k)
 		v = append(v, entries[i].v)
 	}
-	_, _, _, _, err := VerifyRangeProof(trie.Hash(), nil, nil, k, v, nil)
+	_, _, err := VerifyRangeProof(trie.Hash(), nil, nil, k, v, nil)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -429,7 +429,7 @@ func TestAllElementsProof(t *testing.T) {
 	if err := trie.Prove(entries[len(entries)-1].k, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err = VerifyRangeProof(trie.Hash(), k[0], k[len(k)-1], k, v, proof)
+	_, _, err = VerifyRangeProof(trie.Hash(), k[0], k[len(k)-1], k, v, proof)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -444,7 +444,7 @@ func TestAllElementsProof(t *testing.T) {
 	if err := trie.Prove(last, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err = VerifyRangeProof(trie.Hash(), first, last, k, v, proof)
+	_, _, err = VerifyRangeProof(trie.Hash(), first, last, k, v, proof)
 	if err != nil {
 		t.Fatalf("Expected no error, got %v", err)
 	}
@@ -477,7 +477,7 @@ func TestSingleSideRangeProof(t *testing.T) {
 				k = append(k, entries[i].k)
 				v = append(v, entries[i].v)
 			}
-			_, _, _, _, err := VerifyRangeProof(trie.Hash(), common.Hash{}.Bytes(), k[len(k)-1], k, v, proof)
+			_, _, err := VerifyRangeProof(trie.Hash(), common.Hash{}.Bytes(), k[len(k)-1], k, v, proof)
 			if err != nil {
 				t.Fatalf("Expected no error, got %v", err)
 			}
@@ -513,7 +513,7 @@ func TestReverseSingleSideRangeProof(t *testing.T) {
 				k = append(k, entries[i].k)
 				v = append(v, entries[i].v)
 			}
-			_, _, _, _, err := VerifyRangeProof(trie.Hash(), k[0], last.Bytes(), k, v, proof)
+			_, _, err := VerifyRangeProof(trie.Hash(), k[0], last.Bytes(), k, v, proof)
 			if err != nil {
 				t.Fatalf("Expected no error, got %v", err)
 			}
@@ -585,7 +585,7 @@ func TestBadRangeProof(t *testing.T) {
 			index = mrand.Intn(end - start)
 			vals[index] = nil
 		}
-		_, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof)
+		_, _, err := VerifyRangeProof(trie.Hash(), first, last, keys, vals, proof)
 		if err == nil {
 			t.Fatalf("%d Case %d index %d range: (%d->%d) expect error, got nil", i, testcase, index, start, end-1)
 		}
@@ -619,7 +619,7 @@ func TestGappedRangeProof(t *testing.T) {
 		keys = append(keys, entries[i].k)
 		vals = append(vals, entries[i].v)
 	}
-	_, _, _, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof)
+	_, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof)
 	if err == nil {
 		t.Fatal("expect error, got nil")
 	}
@@ -646,7 +646,7 @@ func TestSameSideProofs(t *testing.T) {
 	if err := trie.Prove(last, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err := VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof)
+	_, _, err := VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof)
 	if err == nil {
 		t.Fatalf("Expected error, got nil")
 	}
@@ -662,7 +662,7 @@ func TestSameSideProofs(t *testing.T) {
 	if err := trie.Prove(last, 0, proof); err != nil {
 		t.Fatalf("Failed to prove the last node %v", err)
 	}
-	_, _, _, _, err = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof)
+	_, _, err = VerifyRangeProof(trie.Hash(), first, last, [][]byte{entries[pos].k}, [][]byte{entries[pos].v}, proof)
 	if err == nil {
 		t.Fatalf("Expected error, got nil")
 	}
@@ -730,7 +730,7 @@ func TestHasRightElement(t *testing.T) {
 			k = append(k, entries[i].k)
 			v = append(v, entries[i].v)
 		}
-		_, _, _, hasMore, err := VerifyRangeProof(trie.Hash(), firstKey, lastKey, k, v, proof)
+		_, hasMore, err := VerifyRangeProof(trie.Hash(), firstKey, lastKey, k, v, proof)
 		if err != nil {
 			t.Fatalf("Expected no error, got %v", err)
 		}
@@ -763,25 +763,19 @@ func TestEmptyRangeProof(t *testing.T) {
 		if err := trie.Prove(first, 0, proof); err != nil {
 			t.Fatalf("Failed to prove the first node %v", err)
 		}
-		db, tr, not, _, err := VerifyRangeProof(trie.Hash(), first, nil, nil, nil, proof)
+		db, _, err := VerifyRangeProof(trie.Hash(), first, nil, nil, nil, proof)
 		if c.err && err == nil {
 			t.Fatalf("Expected error, got nil")
 		}
 		if !c.err && err != nil {
 			t.Fatalf("Expected no error, got %v", err)
 		}
-		// If no error was returned, ensure the returned trie and database contains
+		// If no error was returned, ensure the returned database contains
 		// the entire proof, since there's no value
 		if !c.err {
-			if err := tr.Prove(first, 0, memorydb.New()); err != nil {
-				t.Errorf("returned trie doesn't contain original proof: %v", err)
-			}
 			if memdb := db.(*memorydb.Database); memdb.Len() != proof.Len() {
 				t.Errorf("database entry count mismatch: have %d, want %d", memdb.Len(), proof.Len())
 			}
-			if not == nil {
-				t.Errorf("missing notary")
-			}
 		}
 	}
 }
@@ -800,6 +794,8 @@ func TestBloatedProof(t *testing.T) {
 	var vals [][]byte
 
 	proof := memorydb.New()
+	// In the 'malicious' case, we add proofs for every single item
+	// (but only one key/value pair used as leaf)
 	for i, entry := range entries {
 		trie.Prove(entry.k, 0, proof)
 		if i == 50 {
@@ -807,12 +803,15 @@ func TestBloatedProof(t *testing.T) {
 			vals = append(vals, entry.v)
 		}
 	}
+	// For reference, we use the same function, but _only_ prove the first
+	// and last element
 	want := memorydb.New()
 	trie.Prove(keys[0], 0, want)
 	trie.Prove(keys[len(keys)-1], 0, want)
 
-	_, _, notary, _, _ := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof)
+	db, _, _ := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, vals, proof)
-	if used := notary.Accessed().(*memorydb.Database); used.Len() != want.Len() {
+	// The db should not contain anything of the bloated data
+	if used := db.(*memorydb.Database); used.Len() != want.Len() {
 		t.Fatalf("notary proof size mismatch: have %d, want %d", used.Len(), want.Len())
 	}
 }
@@ -917,13 +916,40 @@ func benchmarkVerifyRangeProof(b *testing.B, size int) {
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		_, _, _, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, values, proof)
+		_, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, values, proof)
 		if err != nil {
 			b.Fatalf("Case %d(%d->%d) expect no error, got %v", i, start, end-1, err)
 		}
 	}
 }
 
+func BenchmarkVerifyRangeNoProof10(b *testing.B)   { benchmarkVerifyRangeNoProof(b, 100) }
+func BenchmarkVerifyRangeNoProof500(b *testing.B)  { benchmarkVerifyRangeNoProof(b, 500) }
+func BenchmarkVerifyRangeNoProof1000(b *testing.B) { benchmarkVerifyRangeNoProof(b, 1000) }
+
+func benchmarkVerifyRangeNoProof(b *testing.B, size int) {
+	trie, vals := randomTrie(size)
+	var entries entrySlice
+	for _, kv := range vals {
+		entries = append(entries, kv)
+	}
+	sort.Sort(entries)
+
+	var keys [][]byte
+	var values [][]byte
+	for _, entry := range entries {
+		keys = append(keys, entry.k)
+		values = append(values, entry.v)
+	}
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _, err := VerifyRangeProof(trie.Hash(), keys[0], keys[len(keys)-1], keys, values, nil)
+		if err != nil {
+			b.Fatalf("Expected no error, got %v", err)
+		}
+	}
+}
+
 func randomTrie(n int) (*Trie, map[string]*kv) {
 	trie := new(Trie)
 	vals := make(map[string]*kv)