diff --git a/Makefile b/Makefile
index e15356c2c..ae2c71610 100644
--- a/Makefile
+++ b/Makefile
@@ -62,12 +62,16 @@ get_vendor_deps:
 	@echo "--> Running glide install"
 	@glide install
 
+
 ########################################
 ### Testing
 
 test:
 	go test -tags gcc `glide novendor`
 
+test100:
+	@for i in {1..100}; do make test; done
+
 
 ########################################
 ### Formatting, linting, and vetting
diff --git a/cli/setup.go b/cli/setup.go
index 295477598..2dcadb407 100644
--- a/cli/setup.go
+++ b/cli/setup.go
@@ -8,9 +8,6 @@ import (
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
-
-	data "github.com/tendermint/go-wire/data"
-	"github.com/tendermint/go-wire/data/base58"
 )
 
 const (
@@ -42,7 +39,7 @@ func PrepareBaseCmd(cmd *cobra.Command, envPrefix, defaultHome string) Executor
 func PrepareMainCmd(cmd *cobra.Command, envPrefix, defaultHome string) Executor {
 	cmd.PersistentFlags().StringP(EncodingFlag, "e", "hex", "Binary encoding (hex|b64|btc)")
 	cmd.PersistentFlags().StringP(OutputFlag, "o", "text", "Output format (text|json)")
-	cmd.PersistentPreRunE = concatCobraCmdFuncs(setEncoding, validateOutput, cmd.PersistentPreRunE)
+	cmd.PersistentPreRunE = concatCobraCmdFuncs(validateOutput, cmd.PersistentPreRunE)
 	return PrepareBaseCmd(cmd, envPrefix, defaultHome)
 }
 
@@ -147,23 +144,6 @@ func bindFlagsLoadViper(cmd *cobra.Command, args []string) error {
 	return nil
 }
 
-// setEncoding reads the encoding flag
-func setEncoding(cmd *cobra.Command, args []string) error {
-	// validate and set encoding
-	enc := viper.GetString("encoding")
-	switch enc {
-	case "hex":
-		data.Encoder = data.HexEncoder
-	case "b64":
-		data.Encoder = data.B64Encoder
-	case "btc":
-		data.Encoder = base58.BTCEncoder
-	default:
-		return errors.Errorf("Unsupported encoding: %s", enc)
-	}
-	return nil
-}
-
 func validateOutput(cmd *cobra.Command, args []string) error {
 	// validate output format
 	output := viper.GetString(OutputFlag)
diff --git a/common/repeat_timer.go b/common/repeat_timer.go
index 2e6cb81c8..cb227199e 100644
--- a/common/repeat_timer.go
+++ b/common/repeat_timer.go
@@ -80,13 +80,11 @@ func (t *logicalTicker) fireRoutine(interval time.Duration) {
 	}
 	// Init `lasttime` end
 
-	timeleft := interval
 	for {
 		select {
 		case newtime := <-source:
 			elapsed := newtime.Sub(lasttime)
-			timeleft -= elapsed
-			if timeleft <= 0 {
+			if interval <= elapsed {
 				// Block for determinism until the ticker is stopped.
 				select {
 				case t.ch <- newtime:
@@ -97,7 +95,7 @@ func (t *logicalTicker) fireRoutine(interval time.Duration) {
 				// Don't try to "catch up" by sending more.
 				// "Ticker adjusts the intervals or drops ticks to make up for
 				// slow receivers" - https://golang.org/pkg/time/#Ticker
-				timeleft = interval
+				lasttime = newtime
 			}
 		case <-t.quit:
 			return // done
diff --git a/common/repeat_timer_test.go b/common/repeat_timer_test.go
index 5a3a4c0a6..5598922c5 100644
--- a/common/repeat_timer_test.go
+++ b/common/repeat_timer_test.go
@@ -1,6 +1,7 @@
 package common
 
 import (
+	"sync"
 	"testing"
 	"time"
 
@@ -13,29 +14,42 @@ func TestDefaultTicker(t *testing.T) {
 	ticker.Stop()
 }
 
-func TestRepeat(t *testing.T) {
+func TestRepeatTimer(t *testing.T) {
 
 	ch := make(chan time.Time, 100)
-	lt := time.Time{} // zero time is year 1
+	mtx := new(sync.Mutex)
 
-	// tick fires `cnt` times for each second.
-	tick := func(cnt int) {
-		for i := 0; i < cnt; i++ {
-			lt = lt.Add(time.Second)
-			ch <- lt
-		}
+	// tick() fires from start to end
+	// (exclusive) in milliseconds with incr.
+	// It locks on mtx, so subsequent calls
+	// run in series.
+	tick := func(startMs, endMs, incrMs time.Duration) {
+		mtx.Lock()
+		go func() {
+			for tMs := startMs; tMs < endMs; tMs += incrMs {
+				lt := time.Time{}
+				lt = lt.Add(tMs * time.Millisecond)
+				ch <- lt
+			}
+			mtx.Unlock()
+		}()
 	}
 
-	// tock consumes Ticker.Chan() events `cnt` times.
-	tock := func(t *testing.T, rt *RepeatTimer, cnt int) {
-		for i := 0; i < cnt; i++ {
-			timeout := time.After(time.Second * 10)
-			select {
-			case <-rt.Chan():
-			case <-timeout:
-				panic("expected RepeatTimer to fire")
-			}
+	// tock consumes Ticker.Chan() events and checks them against the ms in "timesMs".
+	tock := func(t *testing.T, rt *RepeatTimer, timesMs []int64) {
+
+		// Check against timesMs.
+		for _, timeMs := range timesMs {
+			tyme := <-rt.Chan()
+			sinceMs := tyme.Sub(time.Time{}) / time.Millisecond
+			assert.Equal(t, timeMs, int64(sinceMs))
 		}
+
+		// TODO detect number of running
+		// goroutines to ensure that
+		// no other times will fire.
+		// See https://github.com/tendermint/tmlibs/issues/120.
+		time.Sleep(time.Millisecond * 100)
 		done := true
 		select {
 		case <-rt.Chan():
@@ -46,46 +60,44 @@ func TestRepeat(t *testing.T) {
 	}
 
 	tm := NewLogicalTickerMaker(ch)
-	dur := time.Duration(10 * time.Millisecond) // less than a second
-	rt := NewRepeatTimerWithTickerMaker("bar", dur, tm)
-
-	// Start at 0.
-	tock(t, rt, 0)
-	tick(1) // init time
+	rt := NewRepeatTimerWithTickerMaker("bar", time.Second, tm)
 
-	tock(t, rt, 0)
-	tick(1) // wait 1 periods
-	tock(t, rt, 1)
-	tick(2) // wait 2 periods
-	tock(t, rt, 2)
-	tick(3) // wait 3 periods
-	tock(t, rt, 3)
-	tick(4) // wait 4 periods
-	tock(t, rt, 4)
-
-	// Multiple resets leads to no firing.
-	for i := 0; i < 20; i++ {
-		time.Sleep(time.Millisecond)
-		rt.Reset()
-	}
+	/* NOTE: Useful for debugging deadlocks...
+	go func() {
+		time.Sleep(time.Second * 3)
+		trace := make([]byte, 102400)
+		count := runtime.Stack(trace, true)
+		fmt.Printf("Stack of %d bytes: %s\n", count, trace)
+	}()
+	*/
 
-	// After this, it works as new.
-	tock(t, rt, 0)
-	tick(1) // init time
+	tick(0, 1000, 10)
+	tock(t, rt, []int64{})
+	tick(1000, 2000, 10)
+	tock(t, rt, []int64{1000})
+	tick(2005, 5000, 10)
+	tock(t, rt, []int64{2005, 3005, 4005})
+	tick(5001, 5999, 1)
+	// Read 5005 instead of 5001 because
+	// it's 1 second greater than 4005.
+	tock(t, rt, []int64{5005})
+	tick(6000, 7005, 1)
+	tock(t, rt, []int64{6005})
+	tick(7033, 8032, 1)
+	tock(t, rt, []int64{7033})
 
-	tock(t, rt, 0)
-	tick(1) // wait 1 periods
-	tock(t, rt, 1)
-	tick(2) // wait 2 periods
-	tock(t, rt, 2)
-	tick(3) // wait 3 periods
-	tock(t, rt, 3)
-	tick(4) // wait 4 periods
-	tock(t, rt, 4)
+	// After a reset, nothing happens
+	// until two ticks are received.
+	rt.Reset()
+	tock(t, rt, []int64{})
+	tick(8040, 8041, 1)
+	tock(t, rt, []int64{})
+	tick(9555, 9556, 1)
+	tock(t, rt, []int64{9555})
 
 	// After a stop, nothing more is sent.
 	rt.Stop()
-	tock(t, rt, 0)
+	tock(t, rt, []int64{})
 
 	// Another stop panics.
 	assert.Panics(t, func() { rt.Stop() })
diff --git a/db/backend_test.go b/db/backend_test.go
index 0f4346f2e..80fbbb140 100644
--- a/db/backend_test.go
+++ b/db/backend_test.go
@@ -15,7 +15,7 @@ func cleanupDBDir(dir, name string) {
 	os.RemoveAll(filepath.Join(dir, name) + ".db")
 }
 
-func testBackendGetSetDelete(t *testing.T, backend string) {
+func testBackendGetSetDelete(t *testing.T, backend DBBackendType) {
 	// Default
 	dir, dirname := cmn.Tempdir(fmt.Sprintf("test_backend_%s_", backend))
 	defer dir.Close()
@@ -141,9 +141,9 @@ func TestBackendsNilKeys(t *testing.T) {
 	}
 }
 
-func TestGoLevelDBBackendStr(t *testing.T) {
+func TestGoLevelDBBackend(t *testing.T) {
 	name := cmn.Fmt("test_%x", cmn.RandStr(12))
-	db := NewDB(name, GoLevelDBBackendStr, "")
+	db := NewDB(name, GoLevelDBBackend, "")
 	defer cleanupDBDir("", name)
 
 	_, ok := db.(*GoLevelDB)
diff --git a/db/c_level_db.go b/db/c_level_db.go
index f1a5a3aef..a59137883 100644
--- a/db/c_level_db.go
+++ b/db/c_level_db.go
@@ -14,8 +14,8 @@ func init() {
 	dbCreator := func(name string, dir string) (DB, error) {
 		return NewCLevelDB(name, dir)
 	}
-	registerDBCreator(LevelDBBackendStr, dbCreator, true)
-	registerDBCreator(CLevelDBBackendStr, dbCreator, false)
+	registerDBCreator(LevelDBBackend, dbCreator, true)
+	registerDBCreator(CLevelDBBackend, dbCreator, false)
 }
 
 var _ DB = (*CLevelDB)(nil)
diff --git a/db/c_level_db_test.go b/db/c_level_db_test.go
index 89993fbac..34bb72273 100644
--- a/db/c_level_db_test.go
+++ b/db/c_level_db_test.go
@@ -86,9 +86,9 @@ func bytes2Int64(buf []byte) int64 {
 }
 */
 
-func TestCLevelDBBackendStr(t *testing.T) {
+func TestCLevelDBBackend(t *testing.T) {
 	name := cmn.Fmt("test_%x", cmn.RandStr(12))
-	db := NewDB(name, LevelDBBackendStr, "")
+	db := NewDB(name, LevelDBBackend, "")
 	defer cleanupDBDir("", name)
 
 	_, ok := db.(*CLevelDB)
diff --git a/db/common_test.go b/db/common_test.go
index 2a5d01818..1b0f00416 100644
--- a/db/common_test.go
+++ b/db/common_test.go
@@ -45,7 +45,7 @@ func checkValuePanics(t *testing.T, itr Iterator) {
 	assert.Panics(t, func() { itr.Key() }, "checkValuePanics expected panic but didn't")
 }
 
-func newTempDB(t *testing.T, backend string) (db DB) {
+func newTempDB(t *testing.T, backend DBBackendType) (db DB) {
 	dir, dirname := cmn.Tempdir("test_go_iterator")
 	db = NewDB("testdb", backend, dirname)
 	dir.Close()
diff --git a/db/db.go b/db/db.go
index 25ff93ec5..869937660 100644
--- a/db/db.go
+++ b/db/db.go
@@ -5,19 +5,21 @@ import "fmt"
 //----------------------------------------
 // Main entry
 
+type DBBackendType string
+
 const (
-	LevelDBBackendStr   = "leveldb" // legacy, defaults to goleveldb unless +gcc
-	CLevelDBBackendStr  = "cleveldb"
-	GoLevelDBBackendStr = "goleveldb"
-	MemDBBackendStr     = "memdb"
-	FSDBBackendStr      = "fsdb" // using the filesystem naively
+	LevelDBBackend   DBBackendType = "leveldb" // legacy, defaults to goleveldb unless +gcc
+	CLevelDBBackend  DBBackendType = "cleveldb"
+	GoLevelDBBackend DBBackendType = "goleveldb"
+	MemDBBackend     DBBackendType = "memdb"
+	FSDBBackend      DBBackendType = "fsdb" // using the filesystem naively
 )
 
 type dbCreator func(name string, dir string) (DB, error)
 
-var backends = map[string]dbCreator{}
+var backends = map[DBBackendType]dbCreator{}
 
-func registerDBCreator(backend string, creator dbCreator, force bool) {
+func registerDBCreator(backend DBBackendType, creator dbCreator, force bool) {
 	_, ok := backends[backend]
 	if !force && ok {
 		return
@@ -25,7 +27,7 @@ func registerDBCreator(backend string, creator dbCreator, force bool) {
 	backends[backend] = creator
 }
 
-func NewDB(name string, backend string, dir string) DB {
+func NewDB(name string, backend DBBackendType, dir string) DB {
 	db, err := backends[backend](name, dir)
 	if err != nil {
 		panic(fmt.Sprintf("Error initializing DB: %v", err))
diff --git a/db/fsdb.go b/db/fsdb.go
index 45c3231f6..578c1785a 100644
--- a/db/fsdb.go
+++ b/db/fsdb.go
@@ -19,7 +19,7 @@ const (
 )
 
 func init() {
-	registerDBCreator(FSDBBackendStr, func(name string, dir string) (DB, error) {
+	registerDBCreator(FSDBBackend, func(name string, dir string) (DB, error) {
 		dbPath := filepath.Join(dir, name+".db")
 		return NewFSDB(dbPath), nil
 	}, false)
diff --git a/db/go_level_db.go b/db/go_level_db.go
index 7d60e060f..9fed329bf 100644
--- a/db/go_level_db.go
+++ b/db/go_level_db.go
@@ -17,8 +17,8 @@ func init() {
 	dbCreator := func(name string, dir string) (DB, error) {
 		return NewGoLevelDB(name, dir)
 	}
-	registerDBCreator(LevelDBBackendStr, dbCreator, false)
-	registerDBCreator(GoLevelDBBackendStr, dbCreator, false)
+	registerDBCreator(LevelDBBackend, dbCreator, false)
+	registerDBCreator(GoLevelDBBackend, dbCreator, false)
 }
 
 var _ DB = (*GoLevelDB)(nil)
diff --git a/db/mem_db.go b/db/mem_db.go
index 1e3bee5a5..f2c484fa7 100644
--- a/db/mem_db.go
+++ b/db/mem_db.go
@@ -7,7 +7,7 @@ import (
 )
 
 func init() {
-	registerDBCreator(MemDBBackendStr, func(name string, dir string) (DB, error) {
+	registerDBCreator(MemDBBackend, func(name string, dir string) (DB, error) {
 		return NewMemDB(), nil
 	}, false)
 }
diff --git a/glide.lock b/glide.lock
index aaf7c07e2..875f9837b 100644
--- a/glide.lock
+++ b/glide.lock
@@ -1,10 +1,14 @@
-hash: 325b2f9c7e84696f88fa88126a22eb1e1e91c2be5f60402d17bfaad6713b33c2
-updated: 2017-12-28T18:27:21.247160207-08:00
+hash: 22e22759d9adc51e3ce0728955143321386891907ce54eb952245d57285d8784
+updated: 2018-02-02T18:08:31.85309+01:00
 imports:
+- name: github.com/davecgh/go-spew
+  version: 346938d642f2ec3594ed81d874461961cd0faa76
+  subpackages:
+  - spew
 - name: github.com/fsnotify/fsnotify
-  version: 4da3e2cfbabc9f751898f250b49f2439785783a1
+  version: c2828203cd70a50dcccfb2761f8b1f8ceef9a8e9
 - name: github.com/go-kit/kit
-  version: e2b298466b32c7cd5579a9b9b07e968fc9d9452c
+  version: 4dc7be5d2d12881735283bcab7352178e190fc71
   subpackages:
   - log
   - log/level
@@ -14,7 +18,7 @@ imports:
 - name: github.com/go-stack/stack
   version: 817915b46b97fd7bb80e8ab6b69f01a53ac3eebf
 - name: github.com/gogo/protobuf
-  version: 342cbe0a04158f6dcb03ca0079991a51a4248c02
+  version: 1adfc126b41513cc696b209667c8656ea7aac67c
   subpackages:
   - gogoproto
   - proto
@@ -39,21 +43,15 @@ imports:
 - name: github.com/kr/logfmt
   version: b84e30acd515aadc4b783ad4ff83aff3299bdfe0
 - name: github.com/magiconair/properties
-  version: 8d7837e64d3c1ee4e54a880c5a920ab4316fc90a
-- name: github.com/mattn/go-colorable
-  version: 6fcc0c1fd9b620311d821b106a400b35dc95c497
-- name: github.com/mattn/go-isatty
-  version: a5cdd64afdee435007ee3e9f6ed4684af949d568
+  version: 49d762b9817ba1c2e9d0c69183c2b4a8b8f1d934
 - name: github.com/mitchellh/mapstructure
-  version: 06020f85339e21b2478f756a78e295255ffa4d6a
-- name: github.com/pelletier/go-buffruneio
-  version: c37440a7cf42ac63b919c752ca73a85067e05992
+  version: b4575eea38cca1123ec2dc90c26529b5c5acfcff
 - name: github.com/pelletier/go-toml
-  version: 13d49d4606eb801b8f01ae542b4afc4c6ee3d84a
+  version: acdc4509485b587f5e675510c4f2c63e90ff68a8
 - name: github.com/pkg/errors
   version: 645ef00459ed84a119197bfb8d8205042c6df63d
 - name: github.com/spf13/afero
-  version: 5660eeed305fe5f69c8fc6cf899132a459a97064
+  version: bb8f1927f2a9d3ab41c9340aa034f6b803f4359c
   subpackages:
   - mem
 - name: github.com/spf13/cast
@@ -61,11 +59,11 @@ imports:
 - name: github.com/spf13/cobra
   version: 7b2c5ac9fc04fc5efafb60700713d4fa609b777b
 - name: github.com/spf13/jwalterweatherman
-  version: 12bd96e66386c1960ab0f74ced1362f66f552f7b
+  version: 7c0cea34c8ece3fbeb2b27ab9b59511d360fb394
 - name: github.com/spf13/pflag
   version: 97afa5e7ca8a08a383cb259e06636b5e2cc7897f
 - name: github.com/spf13/viper
-  version: 8ef37cbca71638bf32f3d5e194117d4cb46da163
+  version: 25b30aa063fc18e48662b86996252eabdcf2f0c7
 - name: github.com/syndtr/goleveldb
   version: b89cc31ef7977104127d34c1bd31ebd1a9db2199
   subpackages:
@@ -82,20 +80,13 @@ imports:
   - leveldb/table
   - leveldb/util
 - name: github.com/tendermint/go-wire
-  version: 27be46e25124ddf775e23317a83647ce62a93f6b
-  subpackages:
-  - data
-  - data/base58
-- name: github.com/tendermint/log15
-  version: f91285dece9f4875421b481da3e613d83d44f29b
-  subpackages:
-  - term
+  version: e723d95ac2838b7ae9919ada25004859236c32ff
 - name: golang.org/x/crypto
   version: edd5e9b0879d13ee6970a50153d85b8fec9f7686
   subpackages:
   - ripemd160
 - name: golang.org/x/sys
-  version: 8dbc5d05d6edcc104950cc299a1ce6641235bc86
+  version: 37707fdb30a5b38865cfb95e5aab41707daec7fd
   subpackages:
   - unix
 - name: golang.org/x/text
@@ -104,18 +95,14 @@ imports:
   - transform
   - unicode/norm
 - name: gopkg.in/yaml.v2
-  version: eb3733d160e74a9c7e442f435eb3bea458e1d19f
+  version: d670f9405373e636a5a2765eea47fac0c9bc91a4
 testImports:
-- name: github.com/davecgh/go-spew
-  version: 04cdfd42973bb9c8589fd6a731800cf222fde1a9
-  subpackages:
-  - spew
 - name: github.com/pmezard/go-difflib
   version: d8ed2627bdf02c080bf22230dbb337003b7aba2d
   subpackages:
   - difflib
 - name: github.com/stretchr/testify
-  version: 2aa2c176b9dab406a6970f6a55f513e8a8c8b18f
+  version: 12b6f73e6084dad08a7c6e575284b177ecafbc71
   subpackages:
   - assert
   - require
diff --git a/glide.yaml b/glide.yaml
index 2df880175..42d43e4be 100644
--- a/glide.yaml
+++ b/glide.yaml
@@ -1,30 +1,39 @@
 package: github.com/tendermint/tmlibs
 import:
 - package: github.com/go-kit/kit
+  version: ^0.6.0
   subpackages:
   - log
   - log/level
   - log/term
 - package: github.com/go-logfmt/logfmt
+  version: ^0.3.0
+- package: github.com/gogo/protobuf
+  version: ^1.0.0
+  subpackages:
+  - gogoproto
+  - proto
 - package: github.com/jmhodges/levigo
 - package: github.com/pkg/errors
+  version: ^0.8.0
 - package: github.com/spf13/cobra
+  version: ^0.0.1
 - package: github.com/spf13/viper
+  version: ^1.0.0
 - package: github.com/syndtr/goleveldb
   subpackages:
   - leveldb
   - leveldb/errors
+  - leveldb/iterator
   - leveldb/opt
 - package: github.com/tendermint/go-wire
-  subpackages:
-  - data
-  - data/base58
-- package: github.com/tendermint/log15
+  version: develop
 - package: golang.org/x/crypto
   subpackages:
   - ripemd160
 testImport:
 - package: github.com/stretchr/testify
+  version: ^1.2.1
   subpackages:
   - assert
   - require
diff --git a/merkle/simple_map.go b/merkle/simple_map.go
index 003c7cd42..b09b71d54 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.BinaryBytes(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))
@@ -65,22 +64,22 @@ func (sm *SimpleMap) KVPairs() cmn.KVPairs {
 type kvPair cmn.KVPair
 
 func (kv kvPair) Hash() []byte {
-	hasher, n, err := ripemd160.New(), new(int), new(error)
-	wire.WriteByteSlice(kv.Key, hasher, n, err)
-	if *err != nil {
-		panic(*err)
+	hasher := ripemd160.New()
+	err := wire.EncodeByteSlice(hasher, kv.Key)
+	if err != nil {
+		panic(err)
 	}
-	wire.WriteByteSlice(kv.Value, hasher, n, err)
-	if *err != nil {
-		panic(*err)
+	err = wire.EncodeByteSlice(hasher, kv.Value)
+	if err != nil {
+		panic(err)
 	}
 	return hasher.Sum(nil)
 }
 
 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 8ba7ce66b..61210132b 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, "3bb53f017d2f5b4f144692aa829a5c245ac2b123", 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, "14a68db29e3f930ffaafeff5e07c17a439384f39", 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, "275c6367f4be335f9c482b6ef72e49c84e3f8bda", 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, "275c6367f4be335f9c482b6ef72e49c84e3f8bda", 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, "48d60701cb4c96916f68a958b3368205ebe3809b", 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, "48d60701cb4c96916f68a958b3368205ebe3809b", 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 f75568fd9..83f89e598 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 3a82f4edc..182f2fdaa 100644
--- a/merkle/simple_tree.go
+++ b/merkle/simple_tree.go
@@ -28,17 +28,14 @@ import (
 	"golang.org/x/crypto/ripemd160"
 
 	"github.com/tendermint/go-wire"
-	. "github.com/tendermint/tmlibs/common"
 )
 
 func SimpleHashFromTwoHashes(left []byte, right []byte) []byte {
-	var n int
-	var err error
 	var hasher = ripemd160.New()
-	wire.WriteByteSlice(left, hasher, &n, &err)
-	wire.WriteByteSlice(right, hasher, &n, &err)
+	err := wire.EncodeByteSlice(hasher, left)
+	err = wire.EncodeByteSlice(hasher, right)
 	if err != nil {
-		PanicCrisis(err)
+		panic(err)
 	}
 	return hasher.Sum(nil)
 }
@@ -57,27 +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 {
-	hasher, n, err := ripemd160.New(), new(int), new(error)
-	wire.WriteBinary(item, hasher, n, err)
-	if *err != nil {
-		PanicCrisis(err)
-	}
+func SimpleHashFromBytes(bz []byte) []byte {
+	hasher := ripemd160.New()
+	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()
@@ -86,8 +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 6299fa33b..26f35c807 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 93541eda5..1a6d75e0c 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
 }