diff --git a/glide.lock b/glide.lock
index e23eb217..8ed27e0b 100644
--- a/glide.lock
+++ b/glide.lock
@@ -1,5 +1,5 @@
 hash: 1990fb145d5c5098b5ee467c59506e81b6c3b973667eeb63d83abd7ef831b919
-updated: 2018-01-14T21:24:21.241420637-08:00
+updated: 2018-01-21T03:46:56.821595635-08:00
 imports:
 - name: github.com/davecgh/go-spew
   version: 04cdfd42973bb9c8589fd6a731800cf222fde1a9
@@ -65,7 +65,7 @@ imports:
 - name: github.com/spf13/pflag
   version: 97afa5e7ca8a08a383cb259e06636b5e2cc7897f
 - name: github.com/spf13/viper
-  version: 8ef37cbca71638bf32f3d5e194117d4cb46da163
+  version: 25b30aa063fc18e48662b86996252eabdcf2f0c7
 - name: github.com/syndtr/goleveldb
   version: b89cc31ef7977104127d34c1bd31ebd1a9db2199
   subpackages:
@@ -82,7 +82,7 @@ imports:
   - leveldb/table
   - leveldb/util
 - name: github.com/tendermint/go-wire
-  version: b93ebdd4f306833936c243561ec30af3455dc764
+  version: 0cce10e82786f2d501827fbe158747dbc4ceeb43
 - name: github.com/tendermint/log15
   version: f91285dece9f4875421b481da3e613d83d44f29b
 - name: golang.org/x/crypto
diff --git a/merkle/simple_map.go b/merkle/simple_map.go
index f637d30a..b09b71d5 100644
--- a/merkle/simple_map.go
+++ b/merkle/simple_map.go
@@ -18,25 +18,25 @@ func NewSimpleMap() *SimpleMap {
 	}
 }
 
-func (sm *SimpleMap) Set(key string, value interface{}) {
+func (sm *SimpleMap) Set(key string, value Hasher) {
 	sm.sorted = false
 
-	// Is value Hashable?
-	var vBytes []byte
-	if hashable, ok := value.(Hashable); ok {
-		vBytes = hashable.Hash()
-	} else {
-		vBytes, _ = wire.MarshalBinary(value)
-	}
+	// Hash the key to blind it... why not?
+	khash := SimpleHashFromBytes([]byte(key))
+
+	// And the value is hashed too, so you can
+	// check for equality with a cached value (say)
+	// and make a determination to fetch or not.
+	vhash := value.Hash()
 
 	sm.kvs = append(sm.kvs, cmn.KVPair{
-		Key:   []byte(key),
-		Value: vBytes,
+		Key:   khash,
+		Value: vhash,
 	})
 }
 
-// Merkle root hash of items sorted by key.
-// NOTE: Behavior is undefined when key is duplicate.
+// Merkle root hash of items sorted by key
+// (UNSTABLE: and by value too if duplicate key).
 func (sm *SimpleMap) Hash() []byte {
 	sm.Sort()
 	return hashKVPairs(sm.kvs)
@@ -51,7 +51,6 @@ func (sm *SimpleMap) Sort() {
 }
 
 // Returns a copy of sorted KVPairs.
-// CONTRACT: The returned slice must not be mutated.
 func (sm *SimpleMap) KVPairs() cmn.KVPairs {
 	sm.Sort()
 	kvs := make(cmn.KVPairs, len(sm.kvs))
@@ -78,9 +77,9 @@ func (kv kvPair) Hash() []byte {
 }
 
 func hashKVPairs(kvs cmn.KVPairs) []byte {
-	kvsH := make([]Hashable, 0, len(kvs))
+	kvsH := make([]Hasher, 0, len(kvs))
 	for _, kvp := range kvs {
 		kvsH = append(kvsH, kvPair(kvp))
 	}
-	return SimpleHashFromHashables(kvsH)
+	return SimpleHashFromHashers(kvsH)
 }
diff --git a/merkle/simple_map_test.go b/merkle/simple_map_test.go
index 94685855..61210132 100644
--- a/merkle/simple_map_test.go
+++ b/merkle/simple_map_test.go
@@ -7,41 +7,47 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+type strHasher string
+
+func (str strHasher) Hash() []byte {
+	return SimpleHashFromBytes([]byte(str))
+}
+
 func TestSimpleMap(t *testing.T) {
 	{
 		db := NewSimpleMap()
-		db.Set("key1", "value1")
-		assert.Equal(t, "d7df3e1d47fe38b51f8d897a88828026807a86b6", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		db.Set("key1", strHasher("value1"))
+		assert.Equal(t, "19618304d1ad2635c4238bce87f72331b22a11a1", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
-		db.Set("key1", "value2")
-		assert.Equal(t, "db415336c9be129ac38259b935a49d8e9c248c88", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		db.Set("key1", strHasher("value2"))
+		assert.Equal(t, "51cb96d3d41e1714def72eb4bacc211de9ddf284", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
-		db.Set("key1", "value1")
-		db.Set("key2", "value2")
-		assert.Equal(t, "fdb900a04c1de42bd3d924fc644e28a4bdce30ce", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		db.Set("key1", strHasher("value1"))
+		db.Set("key2", strHasher("value2"))
+		assert.Equal(t, "58a0a99d5019fdcad4bcf55942e833b2dfab9421", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
-		db.Set("key2", "value2") // NOTE: out of order
-		db.Set("key1", "value1")
-		assert.Equal(t, "fdb900a04c1de42bd3d924fc644e28a4bdce30ce", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		db.Set("key2", strHasher("value2")) // NOTE: out of order
+		db.Set("key1", strHasher("value1"))
+		assert.Equal(t, "58a0a99d5019fdcad4bcf55942e833b2dfab9421", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
-		db.Set("key1", "value1")
-		db.Set("key2", "value2")
-		db.Set("key3", "value3")
-		assert.Equal(t, "488cfdaea108ef8bd406f6163555752392ae1b4a", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		db.Set("key1", strHasher("value1"))
+		db.Set("key2", strHasher("value2"))
+		db.Set("key3", strHasher("value3"))
+		assert.Equal(t, "cb56db3c7993e977f4c2789559ae3e5e468a6e9b", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
-		db.Set("key2", "value2") // NOTE: out of order
-		db.Set("key1", "value1")
-		db.Set("key3", "value3")
-		assert.Equal(t, "488cfdaea108ef8bd406f6163555752392ae1b4a", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		db.Set("key2", strHasher("value2")) // NOTE: out of order
+		db.Set("key1", strHasher("value1"))
+		db.Set("key3", strHasher("value3"))
+		assert.Equal(t, "cb56db3c7993e977f4c2789559ae3e5e468a6e9b", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 }
diff --git a/merkle/simple_proof.go b/merkle/simple_proof.go
index f75568fd..83f89e59 100644
--- a/merkle/simple_proof.go
+++ b/merkle/simple_proof.go
@@ -10,8 +10,8 @@ type SimpleProof struct {
 }
 
 // proofs[0] is the proof for items[0].
-func SimpleProofsFromHashables(items []Hashable) (rootHash []byte, proofs []*SimpleProof) {
-	trails, rootSPN := trailsFromHashables(items)
+func SimpleProofsFromHashers(items []Hasher) (rootHash []byte, proofs []*SimpleProof) {
+	trails, rootSPN := trailsFromHashers(items)
 	rootHash = rootSPN.Hash
 	proofs = make([]*SimpleProof, len(items))
 	for i, trail := range trails {
@@ -109,7 +109,7 @@ func (spn *SimpleProofNode) FlattenAunts() [][]byte {
 
 // trails[0].Hash is the leaf hash for items[0].
 // trails[i].Parent.Parent....Parent == root for all i.
-func trailsFromHashables(items []Hashable) (trails []*SimpleProofNode, root *SimpleProofNode) {
+func trailsFromHashers(items []Hasher) (trails []*SimpleProofNode, root *SimpleProofNode) {
 	// Recursive impl.
 	switch len(items) {
 	case 0:
@@ -118,8 +118,8 @@ func trailsFromHashables(items []Hashable) (trails []*SimpleProofNode, root *Sim
 		trail := &SimpleProofNode{items[0].Hash(), nil, nil, nil}
 		return []*SimpleProofNode{trail}, trail
 	default:
-		lefts, leftRoot := trailsFromHashables(items[:(len(items)+1)/2])
-		rights, rightRoot := trailsFromHashables(items[(len(items)+1)/2:])
+		lefts, leftRoot := trailsFromHashers(items[:(len(items)+1)/2])
+		rights, rightRoot := trailsFromHashers(items[(len(items)+1)/2:])
 		rootHash := SimpleHashFromTwoHashes(leftRoot.Hash, rightRoot.Hash)
 		root := &SimpleProofNode{rootHash, nil, nil, nil}
 		leftRoot.Parent = root
diff --git a/merkle/simple_tree.go b/merkle/simple_tree.go
index 86b0bf26..182f2fda 100644
--- a/merkle/simple_tree.go
+++ b/merkle/simple_tree.go
@@ -54,28 +54,25 @@ func SimpleHashFromHashes(hashes [][]byte) []byte {
 	}
 }
 
-// Convenience for SimpleHashFromHashes.
-func SimpleHashFromBinaries(items []interface{}) []byte {
-	hashes := make([][]byte, len(items))
-	for i, item := range items {
-		hashes[i] = SimpleHashFromBinary(item)
+// NOTE: Do not implement this, use SimpleHashFromByteslices instead.
+// type Byteser interface { Bytes() []byte }
+// func SimpleHashFromBytesers(items []Byteser) []byte { ... }
+
+func SimpleHashFromByteslices(bzs [][]byte) []byte {
+	hashes := make([][]byte, len(bzs))
+	for i, bz := range bzs {
+		hashes[i] = SimpleHashFromBytes(bz)
 	}
 	return SimpleHashFromHashes(hashes)
 }
 
-// General Convenience
-func SimpleHashFromBinary(item interface{}) []byte {
+func SimpleHashFromBytes(bz []byte) []byte {
 	hasher := ripemd160.New()
-	bz, err := wire.MarshalBinary(item)
-	if err != nil {
-		panic(err)
-	}
 	hasher.Write(bz)
 	return hasher.Sum(nil)
 }
 
-// Convenience for SimpleHashFromHashes.
-func SimpleHashFromHashables(items []Hashable) []byte {
+func SimpleHashFromHashers(items []Hasher) []byte {
 	hashes := make([][]byte, len(items))
 	for i, item := range items {
 		hash := item.Hash()
@@ -84,8 +81,7 @@ func SimpleHashFromHashables(items []Hashable) []byte {
 	return SimpleHashFromHashes(hashes)
 }
 
-// Convenience for SimpleHashFromHashes.
-func SimpleHashFromMap(m map[string]interface{}) []byte {
+func SimpleHashFromMap(m map[string]Hasher) []byte {
 	sm := NewSimpleMap()
 	for k, v := range m {
 		sm.Set(k, v)
diff --git a/merkle/simple_tree_test.go b/merkle/simple_tree_test.go
index 6299fa33..26f35c80 100644
--- a/merkle/simple_tree_test.go
+++ b/merkle/simple_tree_test.go
@@ -19,14 +19,14 @@ func TestSimpleProof(t *testing.T) {
 
 	total := 100
 
-	items := make([]Hashable, total)
+	items := make([]Hasher, total)
 	for i := 0; i < total; i++ {
 		items[i] = testItem(RandBytes(32))
 	}
 
-	rootHash := SimpleHashFromHashables(items)
+	rootHash := SimpleHashFromHashers(items)
 
-	rootHash2, proofs := SimpleProofsFromHashables(items)
+	rootHash2, proofs := SimpleProofsFromHashers(items)
 
 	if !bytes.Equal(rootHash, rootHash2) {
 		t.Errorf("Unmatched root hashes: %X vs %X", rootHash, rootHash2)
diff --git a/merkle/types.go b/merkle/types.go
index 93541eda..1a6d75e0 100644
--- a/merkle/types.go
+++ b/merkle/types.go
@@ -18,6 +18,6 @@ type Tree interface {
 	IterateRange(start []byte, end []byte, ascending bool, fx func(key []byte, value []byte) (stop bool)) (stopped bool)
 }
 
-type Hashable interface {
+type Hasher interface {
 	Hash() []byte
 }