Simple merkle rfc compatibility (#2713)

* Begin simple merkle compatibility PR

* Fix query_test

* Use trillian test vectors

* Change the split point per RFC 6962

* update spec

* refactor innerhash to match spec

* Update changelog

* Address @liamsi's comments

* Write the comment requested by @liamsi

types/part_set.go

@@ -9,7 +9,6 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/tendermint/tendermint/crypto/merkle"
-	"github.com/tendermint/tendermint/crypto/tmhash"
 	cmn "github.com/tendermint/tendermint/libs/common"
 )
 
@@ -27,16 +26,6 @@ type Part struct {
 	hash []byte
 }
 
-func (part *Part) Hash() []byte {
-	if part.hash != nil {
-		return part.hash
-	}
-	hasher := tmhash.New()
-	hasher.Write(part.Bytes) // nolint: errcheck, gas
-	part.hash = hasher.Sum(nil)
-	return part.hash
-}
-
 // ValidateBasic performs basic validation.
 func (part *Part) ValidateBasic() error {
 	if part.Index < 0 {
@@ -217,7 +206,7 @@ func (ps *PartSet) AddPart(part *Part) (bool, error) {
 	}
 
 	// Check hash proof
-	if part.Proof.Verify(ps.Hash(), part.Hash()) != nil {
+	if part.Proof.Verify(ps.Hash(), part.Bytes) != nil {
 		return false, ErrPartSetInvalidProof
 	}
 

types/results_test.go

@@ -38,7 +38,7 @@ func TestABCIResults(t *testing.T) {
 
 	for i, res := range results {
 		proof := results.ProveResult(i)
-		valid := proof.Verify(root, res.Hash())
+		valid := proof.Verify(root, res.Bytes())
 		assert.NoError(t, valid, "%d", i)
 	}
 }

types/tx.go

@@ -31,13 +31,14 @@ func (tx Tx) String() string {
 // Txs is a slice of Tx.
 type Txs []Tx
 
-// Hash returns the simple Merkle root hash of the transactions.
+// Hash returns the Merkle root hash of the transaction hashes.
+// i.e. the leaves of the tree are the hashes of the txs.
 func (txs Txs) Hash() []byte {
 	// These allocations will be removed once Txs is switched to [][]byte,
 	// ref #2603. This is because golang does not allow type casting slices without unsafe
 	txBzs := make([][]byte, len(txs))
 	for i := 0; i < len(txs); i++ {
-		txBzs[i] = txs[i]
+		txBzs[i] = txs[i].Hash()
 	}
 	return merkle.SimpleHashFromByteSlices(txBzs)
 }
@@ -69,7 +70,7 @@ func (txs Txs) Proof(i int) TxProof {
 	l := len(txs)
 	bzs := make([][]byte, l)
 	for i := 0; i < l; i++ {
-		bzs[i] = txs[i]
+		bzs[i] = txs[i].Hash()
 	}
 	root, proofs := merkle.SimpleProofsFromByteSlices(bzs)
 
@@ -87,8 +88,8 @@ type TxProof struct {
 	Proof    merkle.SimpleProof
 }
 
-// LeadHash returns the hash of the this proof refers to.
-func (tp TxProof) LeafHash() []byte {
+// Leaf returns the hash(tx), which is the leaf in the merkle tree which this proof refers to.
+func (tp TxProof) Leaf() []byte {
 	return tp.Data.Hash()
 }
 
@@ -104,7 +105,7 @@ func (tp TxProof) Validate(dataHash []byte) error {
 	if tp.Proof.Total <= 0 {
 		return errors.New("Proof total must be positive")
 	}
-	valid := tp.Proof.Verify(tp.RootHash, tp.LeafHash())
+	valid := tp.Proof.Verify(tp.RootHash, tp.Leaf())
 	if valid != nil {
 		return errors.New("Proof is not internally consistent")
 	}

types/tx_test.go

@@ -66,14 +66,13 @@ func TestValidTxProof(t *testing.T) {
 		root := txs.Hash()
 		// make sure valid proof for every tx
 		for i := range txs {
-			leaf := txs[i]
-			leafHash := leaf.Hash()
+			tx := []byte(txs[i])
 			proof := txs.Proof(i)
 			assert.Equal(t, i, proof.Proof.Index, "%d: %d", h, i)
 			assert.Equal(t, len(txs), proof.Proof.Total, "%d: %d", h, i)
 			assert.EqualValues(t, root, proof.RootHash, "%d: %d", h, i)
-			assert.EqualValues(t, leaf, proof.Data, "%d: %d", h, i)
-			assert.EqualValues(t, leafHash, proof.LeafHash(), "%d: %d", h, i)
+			assert.EqualValues(t, tx, proof.Data, "%d: %d", h, i)
+			assert.EqualValues(t, txs[i].Hash(), proof.Leaf(), "%d: %d", h, i)
 			assert.Nil(t, proof.Validate(root), "%d: %d", h, i)
 			assert.NotNil(t, proof.Validate([]byte("foobar")), "%d: %d", h, i)