tmhash

merkle/simple_map.go

@@ -2,7 +2,7 @@ package merkle
 
 import (
 	cmn "github.com/tendermint/tmlibs/common"
-	"golang.org/x/crypto/ripemd160"
+	"github.com/tendermint/tmlibs/merkle/tmhash"
 )
 
 type SimpleMap struct {
@@ -63,7 +63,7 @@ func (sm *SimpleMap) KVPairs() cmn.KVPairs {
 type KVPair cmn.KVPair
 
 func (kv KVPair) Hash() []byte {
-	hasher := ripemd160.New()
+	hasher := tmhash.New()
 	err := encodeByteSlice(hasher, kv.Key)
 	if err != nil {
 		panic(err)

merkle/simple_tree.go

@@ -25,11 +25,11 @@ For larger datasets, use IAVLTree.
 package merkle
 
 import (
-	"golang.org/x/crypto/ripemd160"
+	"github.com/tendermint/tmlibs/merkle/tmhash"
 )
 
 func SimpleHashFromTwoHashes(left []byte, right []byte) []byte {
-	var hasher = ripemd160.New()
+	var hasher = tmhash.New()
 	err := encodeByteSlice(hasher, left)
 	if err != nil {
 		panic(err)
@@ -68,7 +68,7 @@ func SimpleHashFromByteslices(bzs [][]byte) []byte {
 }
 
 func SimpleHashFromBytes(bz []byte) []byte {
-	hasher := ripemd160.New()
+	hasher := tmhash.New()
 	hasher.Write(bz)
 	return hasher.Sum(nil)
 }

merkle/tmhash/hash.go

@@ -0,0 +1,41 @@
+package tmhash
+
+import (
+	"crypto/sha256"
+	"hash"
+)
+
+var (
+	Size      = 20
+	BlockSize = sha256.BlockSize
+)
+
+type sha256trunc struct {
+	sha256 hash.Hash
+}
+
+func (h sha256trunc) Write(p []byte) (n int, err error) {
+	return h.sha256.Write(p)
+}
+func (h sha256trunc) Sum(b []byte) []byte {
+	shasum := h.sha256.Sum(b)
+	return shasum[:Size]
+}
+
+func (h sha256trunc) Reset() {
+	h.sha256.Reset()
+}
+
+func (h sha256trunc) Size() int {
+	return Size
+}
+
+func (h sha256trunc) BlockSize() int {
+	return h.sha256.BlockSize()
+}
+
+func New() hash.Hash {
+	return sha256trunc{
+		sha256: sha256.New(),
+	}
+}

merkle/tmhash/hash_test.go

@@ -0,0 +1,23 @@
+package tmhash_test
+
+import (
+	"crypto/sha256"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tendermint/tmlibs/merkle/tmhash"
+)
+
+func TestHash(t *testing.T) {
+	testVector := []byte("abc")
+	hasher := tmhash.New()
+	hasher.Write(testVector)
+	bz := hasher.Sum(nil)
+
+	hasher = sha256.New()
+	hasher.Write(testVector)
+	bz2 := hasher.Sum(nil)
+	bz2 = bz2[:20]
+
+	assert.Equal(t, bz, bz2)
+}