diff --git a/account/priv_account.go b/account/priv_account.go
index 5ef64ec9a..48e1b75c7 100644
--- a/account/priv_account.go
+++ b/account/priv_account.go
@@ -1,6 +1,7 @@
 package account
 
 import (
+	"github.com/tendermint/ed25519"
 	. "github.com/tendermint/tendermint/common"
 )
 
@@ -12,10 +13,14 @@ type PrivAccount struct {
 
 // Generates a new account with private key.
 func GenPrivAccount() *PrivAccount {
-	privKey := PrivKeyEd25519(CRandBytes(32))
+	privKeyBytes := new([64]byte)
+	copy(privKeyBytes[:32], CRandBytes(32))
+	pubKeyBytes := ed25519.MakePublicKey(privKeyBytes)
+	pubKey := PubKeyEd25519(pubKeyBytes[:])
+	privKey := PrivKeyEd25519(privKeyBytes[:])
 	return &PrivAccount{
-		Address: privKey.PubKey().Address(),
-		PubKey:  privKey.PubKey(),
+		Address: pubKey.Address(),
+		PubKey:  pubKey,
 		PrivKey: privKey,
 	}
 }
diff --git a/account/privkey.go b/account/privkey.go
index ad233d9a9..bf088b5ea 100644
--- a/account/privkey.go
+++ b/account/privkey.go
@@ -1,15 +1,14 @@
 package account
 
 import (
-	"errors"
-
-	"github.com/tendermint/go-ed25519"
+	"github.com/tendermint/ed25519"
 	"github.com/tendermint/tendermint/binary"
 	. "github.com/tendermint/tendermint/common"
 )
 
 // PrivKey is part of PrivAccount and state.PrivValidator.
 type PrivKey interface {
+	TypeByte() byte
 	Sign(msg []byte) Signature
 	PubKey() PubKey
 }
@@ -30,22 +29,21 @@ var _ = binary.RegisterInterface(
 // Implements PrivKey
 type PrivKeyEd25519 []byte
 
-func (key PrivKeyEd25519) TypeByte() byte { return PrivKeyTypeEd25519 }
-
-func (key PrivKeyEd25519) ValidateBasic() error {
-	if len(key) != ed25519.PrivateKeySize {
-		return errors.New("Invalid PrivKeyEd25519 privkey size")
-	}
-	return nil
-}
+func (privKey PrivKeyEd25519) TypeByte() byte { return PrivKeyTypeEd25519 }
 
-func (key PrivKeyEd25519) Sign(msg []byte) Signature {
-	signature := ed25519.SignMessage(msg, key, ed25519.MakePubKey(key))
-	return SignatureEd25519(signature)
+func (privKey PrivKeyEd25519) Sign(msg []byte) Signature {
+	pubKey := privKey.PubKey().(PubKeyEd25519)
+	privKeyBytes := new([64]byte)
+	copy(privKeyBytes[:32], privKey[:])
+	copy(privKeyBytes[32:], pubKey[:])
+	signatureBytes := ed25519.Sign(privKeyBytes, msg)
+	return SignatureEd25519(signatureBytes[:])
 }
 
 func (key PrivKeyEd25519) PubKey() PubKey {
-	return PubKeyEd25519(ed25519.MakePubKey(key))
+	keyBytes := new([64]byte)
+	copy(keyBytes[:], key[:])
+	return PubKeyEd25519(ed25519.MakePublicKey(keyBytes)[:])
 }
 
 func (key PrivKeyEd25519) String() string {
diff --git a/account/pubkey.go b/account/pubkey.go
index 1a9f1c92a..48a58c80f 100644
--- a/account/pubkey.go
+++ b/account/pubkey.go
@@ -3,16 +3,17 @@ package account
 import (
 	"errors"
 
-	"github.com/tendermint/go-ed25519"
+	"github.com/tendermint/ed25519"
 	"github.com/tendermint/tendermint/binary"
 	. "github.com/tendermint/tendermint/common"
 )
 
 // PubKey is part of Account and Validator.
 type PubKey interface {
+	TypeByte() byte
+	IsNil() bool
 	Address() []byte
 	VerifyBytes(msg []byte, sig Signature) bool
-	TypeByte() byte
 }
 
 // Types of PubKey implementations
@@ -35,6 +36,8 @@ type PubKeyNil struct{}
 
 func (key PubKeyNil) TypeByte() byte { return PubKeyTypeNil }
 
+func (key PubKeyNil) IsNil() bool { return true }
+
 func (key PubKeyNil) Address() []byte {
 	panic("PubKeyNil has no address")
 }
@@ -43,6 +46,13 @@ func (key PubKeyNil) VerifyBytes(msg []byte, sig_ Signature) bool {
 	panic("PubKeyNil cannot verify messages")
 }
 
+func (key PubKeyEd25519) ValidateBasic() error {
+	if len(key) != ed25519.PublicKeySize {
+		return errors.New("Invalid PubKeyEd25519 key size")
+	}
+	return nil
+}
+
 func (key PubKeyNil) String() string {
 	return "PubKeyNil{}"
 }
@@ -52,31 +62,25 @@ func (key PubKeyNil) String() string {
 // Implements PubKey
 type PubKeyEd25519 []byte
 
-func (key PubKeyEd25519) TypeByte() byte { return PubKeyTypeEd25519 }
+func (pubKey PubKeyEd25519) TypeByte() byte { return PubKeyTypeEd25519 }
 
-// TODO: Or should this just be BinaryRipemd160(key)? (The difference is the TypeByte.)
-func (key PubKeyEd25519) Address() []byte { return binary.BinaryRipemd160(key) }
+func (pubKey PubKeyEd25519) IsNil() bool { return false }
 
-func (key PubKeyEd25519) ValidateBasic() error {
-	if len(key) != ed25519.PublicKeySize {
-		return errors.New("Invalid PubKeyEd25519 key size")
-	}
-	return nil
-}
+// TODO: Or should this just be BinaryRipemd160(key)? (The difference is the TypeByte.)
+func (pubKey PubKeyEd25519) Address() []byte { return binary.BinaryRipemd160(pubKey) }
 
-func (key PubKeyEd25519) VerifyBytes(msg []byte, sig_ Signature) bool {
+func (pubKey PubKeyEd25519) VerifyBytes(msg []byte, sig_ Signature) bool {
 	sig, ok := sig_.(SignatureEd25519)
 	if !ok {
 		panic("PubKeyEd25519 expects an SignatureEd25519 signature")
 	}
-	v1 := &ed25519.Verify{
-		Message:   msg,
-		PubKey:    key,
-		Signature: sig,
-	}
-	return ed25519.VerifyBatch([]*ed25519.Verify{v1})
+	pubKeyBytes := new([32]byte)
+	copy(pubKeyBytes[:], pubKey)
+	sigBytes := new([64]byte)
+	copy(sigBytes[:], sig)
+	return ed25519.Verify(pubKeyBytes, msg, sigBytes)
 }
 
-func (key PubKeyEd25519) String() string {
-	return Fmt("PubKeyEd25519{%X}", []byte(key))
+func (pubKey PubKeyEd25519) String() string {
+	return Fmt("PubKeyEd25519{%X}", pubKey)
 }
diff --git a/account/signature.go b/account/signature.go
index 428889863..53678f723 100644
--- a/account/signature.go
+++ b/account/signature.go
@@ -1,47 +1,50 @@
 package account
 
 import (
-	"errors"
 	"fmt"
 
-	"github.com/tendermint/go-ed25519"
 	"github.com/tendermint/tendermint/binary"
 	. "github.com/tendermint/tendermint/common"
 )
 
 // Signature is a part of Txs and consensus Votes.
 type Signature interface {
+	TypeByte() byte
 }
 
 // Types of Signature implementations
 const (
+	SignatureTypeNil     = byte(0x00)
 	SignatureTypeEd25519 = byte(0x01)
 )
 
 // for binary.readReflect
 var _ = binary.RegisterInterface(
 	struct{ Signature }{},
+	binary.ConcreteType{SignatureNil{}},
 	binary.ConcreteType{SignatureEd25519{}},
 )
 
 //-------------------------------------
 
+// Implements Signature
+type SignatureNil struct{}
+
+func (sig SignatureNil) TypeByte() byte { return SignatureTypeNil }
+
+func (sig SignatureNil) IsNil() bool { return true }
+
+func (sig SignatureNil) String() string { return "SignatureNil{}" }
+
+//-------------------------------------
+
 // Implements Signature
 type SignatureEd25519 []byte
 
 func (sig SignatureEd25519) TypeByte() byte { return SignatureTypeEd25519 }
 
-func (sig SignatureEd25519) ValidateBasic() error {
-	if len(sig) != ed25519.SignatureSize {
-		return errors.New("Invalid SignatureEd25519 signature size")
-	}
-	return nil
-}
+func (sig SignatureEd25519) IsNil() bool { return false }
 
-func (sig SignatureEd25519) IsZero() bool {
-	return len(sig) == 0
-}
+func (sig SignatureEd25519) IsZero() bool { return len(sig) == 0 }
 
-func (sig SignatureEd25519) String() string {
-	return fmt.Sprintf("%X", Fingerprint(sig))
-}
+func (sig SignatureEd25519) String() string { return fmt.Sprintf("%X", Fingerprint(sig)) }
diff --git a/account/signature_test.go b/account/signature_test.go
index 5c71d5826..8168c5c6c 100644
--- a/account/signature_test.go
+++ b/account/signature_test.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"testing"
 
-	"github.com/tendermint/go-ed25519"
+	"github.com/tendermint/ed25519"
 	"github.com/tendermint/tendermint/binary"
 	. "github.com/tendermint/tendermint/common"
 )
diff --git a/state/priv_validator.go b/state/priv_validator.go
index 326f92ce1..c7afe63bd 100644
--- a/state/priv_validator.go
+++ b/state/priv_validator.go
@@ -16,7 +16,7 @@ import (
 	"github.com/tendermint/tendermint/config"
 	. "github.com/tendermint/tendermint/consensus/types"
 
-	"github.com/tendermint/go-ed25519"
+	"github.com/tendermint/ed25519"
 )
 
 const (
@@ -56,10 +56,11 @@ type PrivValidator struct {
 
 // Generates a new validator with private key.
 func GenPrivValidator() *PrivValidator {
-	privKeyBytes := CRandBytes(32)
-	pubKeyBytes := ed25519.MakePubKey(privKeyBytes)
-	pubKey := account.PubKeyEd25519(pubKeyBytes)
-	privKey := account.PrivKeyEd25519(privKeyBytes)
+	privKeyBytes := new([64]byte)
+	copy(privKeyBytes[:32], CRandBytes(32))
+	pubKeyBytes := ed25519.MakePublicKey(privKeyBytes)
+	pubKey := account.PubKeyEd25519(pubKeyBytes[:])
+	privKey := account.PrivKeyEd25519(privKeyBytes[:])
 	return &PrivValidator{
 		Address:    pubKey.Address(),
 		PubKey:     pubKey,