// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package trie
import (
"bytes"
crand "crypto/rand"
mrand "math/rand"
"testing"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethdb"
)
func init() {
mrand.Seed(time.Now().Unix())
}
// makeProvers creates Merkle trie provers based on different implementations to
// test all variations.
func makeProvers(trie *Trie) []func(key []byte) *ethdb.MemDatabase {
var provers []func(key []byte) *ethdb.MemDatabase
// Create a direct trie based Merkle prover
provers = append(provers, func(key []byte) *ethdb.MemDatabase {
proof := ethdb.NewMemDatabase()
trie.Prove(key, 0, proof)
return proof
})
// Create a leaf iterator based Merkle prover
provers = append(provers, func(key []byte) *ethdb.MemDatabase {
proof := ethdb.NewMemDatabase()
if it := NewIterator(trie.NodeIterator(key)); it.Next() && bytes.Equal(key, it.Key) {
for _, p := range it.Prove() {
proof.Put(crypto.Keccak256(p), p)
}
}
return proof
})
return provers
}
func TestProof(t *testing.T) {
trie, vals := randomTrie(500)
root := trie.Hash()
for i, prover := range makeProvers(trie) {
for _, kv := range vals {
proof := prover(kv.k)
if proof == nil {
t.Fatalf("prover %d: missing key %x while constructing proof", i, kv.k)
}
val, _, err := VerifyProof(root, kv.k, proof)
if err != nil {
t.Fatalf("prover %d: failed to verify proof for key %x: %v\nraw proof: %x", i, kv.k, err, proof)
}
if !bytes.Equal(val, kv.v) {
t.Fatalf("prover %d: verified value mismatch for key %x: have %x, want %x", i, kv.k, val, kv.v)
}
}
}
}
func TestOneElementProof(t *testing.T) {
trie := new(Trie)
updateString(trie, "k", "v")
for i, prover := range makeProvers(trie) {
proof := prover([]byte("k"))
if proof == nil {
t.Fatalf("prover %d: nil proof", i)
}
if proof.Len() != 1 {
t.Errorf("prover %d: proof should have one element", i)
}
val, _, err := VerifyProof(trie.Hash(), []byte("k"), proof)
if err != nil {
t.Fatalf("prover %d: failed to verify proof: %v\nraw proof: %x", i, err, proof)
}
if !bytes.Equal(val, []byte("v")) {
t.Fatalf("prover %d: verified value mismatch: have %x, want 'k'", i, val)
}
}
}
func TestBadProof(t *testing.T) {
trie, vals := randomTrie(800)
root := trie.Hash()
for i, prover := range makeProvers(trie) {
for _, kv := range vals {
proof := prover(kv.k)
if proof == nil {
t.Fatalf("prover %d: nil proof", i)
}
key := proof.Keys()[mrand.Intn(proof.Len())]
val, _ := proof.Get(key)
proof.Delete(key)
mutateByte(val)
proof.Put(crypto.Keccak256(val), val)
if _, _, err := VerifyProof(root, kv.k, proof); err == nil {
t.Fatalf("prover %d: expected proof to fail for key %x", i, kv.k)
}
}
}
}
// Tests that missing keys can also be proven. The test explicitly uses a single
// entry trie and checks for missing keys both before and after the single entry.
func TestMissingKeyProof(t *testing.T) {
trie := new(Trie)
updateString(trie, "k", "v")
for i, key := range []string{"a", "j", "l", "z"} {
proof := ethdb.NewMemDatabase()
trie.Prove([]byte(key), 0, proof)
if proof.Len() != 1 {
t.Errorf("test %d: proof should have one element", i)
}
val, _, err := VerifyProof(trie.Hash(), []byte(key), proof)
if err != nil {
t.Fatalf("test %d: failed to verify proof: %v\nraw proof: %x", i, err, proof)
}
if val != nil {
t.Fatalf("test %d: verified value mismatch: have %x, want nil", i, val)
}
}
}
// mutateByte changes one byte in b.
func mutateByte(b []byte) {
for r := mrand.Intn(len(b)); ; {
new := byte(mrand.Intn(255))
if new != b[r] {
b[r] = new
break
}
}
}
func BenchmarkProve(b *testing.B) {
trie, vals := randomTrie(100)
var keys []string
for k := range vals {
keys = append(keys, k)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
kv := vals[keys[i%len(keys)]]
proofs := ethdb.NewMemDatabase()
if trie.Prove(kv.k, 0, proofs); len(proofs.Keys()) == 0 {
b.Fatalf("zero length proof for %x", kv.k)
}
}
}
func BenchmarkVerifyProof(b *testing.B) {
trie, vals := randomTrie(100)
root := trie.Hash()
var keys []string
var proofs []*ethdb.MemDatabase
for k := range vals {
keys = append(keys, k)
proof := ethdb.NewMemDatabase()
trie.Prove([]byte(k), 0, proof)
proofs = append(proofs, proof)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
im := i % len(keys)
if _, _, err := VerifyProof(root, []byte(keys[im]), proofs[im]); err != nil {
b.Fatalf("key %x: %v", keys[im], err)
}
}
}
func randomTrie(n int) (*Trie, map[string]*kv) {
trie := new(Trie)
vals := make(map[string]*kv)
for i := byte(0); i < 100; i++ {
value := &kv{common.LeftPadBytes([]byte{i}, 32), []byte{i}, false}
value2 := &kv{common.LeftPadBytes([]byte{i + 10}, 32), []byte{i}, false}
trie.Update(value.k, value.v)
trie.Update(value2.k, value2.v)
vals[string(value.k)] = value
vals[string(value2.k)] = value2
}
for i := 0; i < n; i++ {
value := &kv{randBytes(32), randBytes(20), false}
trie.Update(value.k, value.v)
vals[string(value.k)] = value
}
return trie, vals
}
func randBytes(n int) []byte {
r := make([]byte, n)
crand.Read(r)
return r
}
