diff --git a/cmd/commands/tx.go b/cmd/commands/tx.go
index 2e12be06ec..0fe0cd731b 100644
--- a/cmd/commands/tx.go
+++ b/cmd/commands/tx.go
@@ -123,7 +123,7 @@ func sendTxCmd(cmd *cobra.Command, args []string) error {
 
 	// sign that puppy
 	signBytes := tx.SignBytes(chainIDFlag)
-	tx.Inputs[0].Signature = crypto.SignatureS{privKey.Sign(signBytes)}
+	tx.Inputs[0].Signature = crypto.WrapSignature(privKey.Sign(signBytes))
 
 	fmt.Println("Signed SendTx:")
 	fmt.Println(string(wire.JSONBytes(tx)))
@@ -179,7 +179,7 @@ func AppTx(name string, data []byte) error {
 		Data:  data,
 	}
 
-	tx.Input.Signature = crypto.SignatureS{privKey.Sign(tx.SignBytes(chainIDFlag))}
+	tx.Input.Signature = crypto.WrapSignature(privKey.Sign(tx.SignBytes(chainIDFlag)))
 
 	fmt.Println("Signed AppTx:")
 	fmt.Println(string(wire.JSONBytes(tx)))
diff --git a/glide.lock b/glide.lock
index 4c67c14d60..6d57797f72 100644
--- a/glide.lock
+++ b/glide.lock
@@ -70,7 +70,7 @@ imports:
 - name: github.com/tendermint/go-config
   version: 620dcbbd7d587cf3599dedbf329b64311b0c307a
 - name: github.com/tendermint/go-crypto
-  version: 0ca2c6fdb0706001ca4c4b9b80c9f428e8cf39da
+  version: 8ff4ce222d32c2328ff0d2bf121fcd34254c03c1
 - name: github.com/tendermint/go-data
   version: e7fcc6d081ec8518912fcdc103188275f83a3ee5
 - name: github.com/tendermint/go-db
diff --git a/plugins/counter/counter_test.go b/plugins/counter/counter_test.go
index f7c658a9af..6d8168bd7b 100644
--- a/plugins/counter/counter_test.go
+++ b/plugins/counter/counter_test.go
@@ -53,7 +53,7 @@ func TestCounterPlugin(t *testing.T) {
 		signBytes := tx.SignBytes(chainID)
 		// t.Logf("Sign bytes: %X\n", signBytes)
 		sig := test1PrivAcc.Sign(signBytes)
-		tx.Input.Signature = crypto.SignatureS{sig}
+		tx.Input.Signature = crypto.WrapSignature(sig)
 		// t.Logf("Signed TX bytes: %X\n", wire.BinaryBytes(struct{ types.Tx }{tx}))
 
 		// Write request
diff --git a/tests/tendermint/main.go b/tests/tendermint/main.go
index 73ace4ef88..53416c2357 100644
--- a/tests/tendermint/main.go
+++ b/tests/tendermint/main.go
@@ -67,7 +67,7 @@ func main() {
 		// Sign request
 		signBytes := tx.SignBytes(chainID)
 		sig := root.Sign(signBytes)
-		tx.Inputs[0].Signature = crypto.SignatureS{sig}
+		tx.Inputs[0].Signature = crypto.WrapSignature(sig)
 		//fmt.Println("tx:", tx)
 
 		// Write request
@@ -118,7 +118,7 @@ func main() {
 		// Sign request
 		signBytes := tx.SignBytes(chainID)
 		sig := privAccountA.Sign(signBytes)
-		tx.Inputs[0].Signature = crypto.SignatureS{sig}
+		tx.Inputs[0].Signature = crypto.WrapSignature(sig)
 		//fmt.Println("tx:", tx)
 
 		// Write request
diff --git a/tests/tmsp/tmsp_test.go b/tests/tmsp/tmsp_test.go
index 86b4bfbf24..e78f978b2b 100644
--- a/tests/tmsp/tmsp_test.go
+++ b/tests/tmsp/tmsp_test.go
@@ -50,7 +50,7 @@ func TestSendTx(t *testing.T) {
 	signBytes := tx.SignBytes(chainID)
 	// t.Log("Sign bytes: %X\n", signBytes)
 	sig := test1PrivAcc.Sign(signBytes)
-	tx.Inputs[0].Signature = crypto.SignatureS{sig}
+	tx.Inputs[0].Signature = crypto.WrapSignature(sig)
 	// t.Log("Signed TX bytes: %X\n", wire.BinaryBytes(types.TxS{tx}))
 
 	// Write request
@@ -102,7 +102,7 @@ func TestSequence(t *testing.T) {
 		// Sign request
 		signBytes := tx.SignBytes(chainID)
 		sig := test1PrivAcc.Sign(signBytes)
-		tx.Inputs[0].Signature = crypto.SignatureS{sig}
+		tx.Inputs[0].Signature = crypto.WrapSignature(sig)
 		// t.Log("ADDR: %X -> %X\n", tx.Inputs[0].Address, tx.Outputs[0].Address)
 
 		// Write request
@@ -146,7 +146,7 @@ func TestSequence(t *testing.T) {
 		// Sign request
 		signBytes := tx.SignBytes(chainID)
 		sig := privAccountA.Sign(signBytes)
-		tx.Inputs[0].Signature = crypto.SignatureS{sig}
+		tx.Inputs[0].Signature = crypto.WrapSignature(sig)
 		// t.Log("ADDR: %X -> %X\n", tx.Inputs[0].Address, tx.Outputs[0].Address)
 
 		// Write request
diff --git a/types/test_helpers.go b/types/test_helpers.go
index 81e639ee10..02f96b7814 100644
--- a/types/test_helpers.go
+++ b/types/test_helpers.go
@@ -12,9 +12,9 @@ import (
 func PrivAccountFromSecret(secret string) PrivAccount {
 	privKey := crypto.GenPrivKeyEd25519FromSecret([]byte(secret))
 	privAccount := PrivAccount{
-		PrivKeyS: crypto.PrivKeyS{privKey},
+		PrivKeyS: crypto.WrapPrivKey(privKey),
 		Account: Account{
-			PubKey: crypto.PubKeyS{privKey.PubKey()},
+			PubKey: crypto.WrapPubKey(privKey.PubKey()),
 		},
 	}
 	return privAccount
@@ -31,9 +31,9 @@ func RandAccounts(num int, minAmount int64, maxAmount int64) []PrivAccount {
 		}
 
 		privKey := crypto.GenPrivKeyEd25519()
-		pubKey := crypto.PubKeyS{privKey.PubKey()}
+		pubKey := crypto.WrapPubKey(privKey.PubKey())
 		privAccs[i] = PrivAccount{
-			PrivKeyS: crypto.PrivKeyS{privKey},
+			PrivKeyS: crypto.WrapPrivKey(privKey),
 			Account: Account{
 				PubKey:  pubKey,
 				Balance: Coins{Coin{"", balance}},
diff --git a/types/tx.go b/types/tx.go
index d4925bbb65..5b0eb84ba5 100644
--- a/types/tx.go
+++ b/types/tx.go
@@ -104,13 +104,7 @@ func NewTxInput(pubKey crypto.PubKey, coins Coins, sequence int) TxInput {
 		Sequence: sequence,
 	}
 	if sequence == 1 {
-		// safely wrap if needed
-		// TODO: extract this as utility function?
-		ps, ok := pubKey.(crypto.PubKeyS)
-		if !ok {
-			ps = crypto.PubKeyS{pubKey}
-		}
-		input.PubKey = ps
+		input.PubKey = crypto.WrapPubKey(pubKey)
 	}
 	return input
 }
@@ -151,25 +145,21 @@ type SendTx struct {
 func (tx *SendTx) SignBytes(chainID string) []byte {
 	signBytes := wire.BinaryBytes(chainID)
 	sigz := make([]crypto.Signature, len(tx.Inputs))
-	for i, input := range tx.Inputs {
-		sigz[i] = input.Signature.Signature
-		tx.Inputs[i].Signature.Signature = nil
+	for i := range tx.Inputs {
+		sigz[i] = tx.Inputs[i].Signature
+		tx.Inputs[i].Signature = crypto.Signature{}
 	}
 	signBytes = append(signBytes, wire.BinaryBytes(tx)...)
 	for i := range tx.Inputs {
-		tx.Inputs[i].Signature.Signature = sigz[i]
+		tx.Inputs[i].Signature = sigz[i]
 	}
 	return signBytes
 }
 
 func (tx *SendTx) SetSignature(addr []byte, sig crypto.Signature) bool {
-	sigs, ok := sig.(crypto.SignatureS)
-	if !ok {
-		sigs = crypto.SignatureS{sig}
-	}
 	for i, input := range tx.Inputs {
 		if bytes.Equal(input.Address, addr) {
-			tx.Inputs[i].Signature = sigs
+			tx.Inputs[i].Signature = crypto.WrapSignature(sig)
 			return true
 		}
 	}
@@ -193,18 +183,14 @@ type AppTx struct {
 func (tx *AppTx) SignBytes(chainID string) []byte {
 	signBytes := wire.BinaryBytes(chainID)
 	sig := tx.Input.Signature
-	tx.Input.Signature.Signature = nil
+	tx.Input.Signature = crypto.WrapSignature(nil)
 	signBytes = append(signBytes, wire.BinaryBytes(tx)...)
 	tx.Input.Signature = sig
 	return signBytes
 }
 
 func (tx *AppTx) SetSignature(sig crypto.Signature) bool {
-	sigs, ok := sig.(crypto.SignatureS)
-	if !ok {
-		sigs = crypto.SignatureS{sig}
-	}
-	tx.Input.Signature = sigs
+	tx.Input.Signature = crypto.WrapSignature(sig)
 	return true
 }
 
diff --git a/types/tx_test.go b/types/tx_test.go
index 71033cc9e7..fb4da2598d 100644
--- a/types/tx_test.go
+++ b/types/tx_test.go
@@ -109,7 +109,7 @@ func TestSendTxJSON(t *testing.T) {
 	sig := test1PrivAcc.Sign(signBytes)
 	// we handle both raw sig and wrapped sig the same
 	tx.SetSignature(test1PrivAcc.PubKey.Address(), sig)
-	tx2.SetSignature(test1PrivAcc.PubKey.Address(), crypto.SignatureS{sig})
+	tx2.SetSignature(test1PrivAcc.PubKey.Address(), crypto.WrapSignature(sig))
 	assert.Equal(tx, tx2)
 
 	// let's marshal / unmarshal this with signature