diff --git a/Makefile b/Makefile
index f775704a9..c1974c410 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ REPO:=github.com/tendermint/go-crypto
 all: get_vendor_deps metalinter_test test
 
 test:
-	go test `glide novendor`
+	go test -p 1 `glide novendor`
 
 get_vendor_deps: ensure_tools
 	@rm -rf vendor/
diff --git a/glide.lock b/glide.lock
index 1c23d8bea..29124c3db 100644
--- a/glide.lock
+++ b/glide.lock
@@ -1,5 +1,5 @@
-hash: c0a2db1b80c6b1b8aab31c526ce43e22e49b23c893c78b8fdb8546aa2e7b7cc6
-updated: 2017-09-22T10:21:34.220901552-04:00
+hash: a2243bfd21937edf660778300855e7cb72185164641cb278dbf0c220e8a0f60a
+updated: 2017-10-23T17:21:02.40831023+02:00
 imports:
 - name: github.com/bgentry/speakeasy
   version: 4aabc24848ce5fd31929f7d1e4ea74d3709c14cd
@@ -11,16 +11,16 @@ imports:
   - chaincfg/chainhash
   - wire
 - name: github.com/btcsuite/btcutil
-  version: 86346b5a958c0cf94186b87855469ae991be501c
+  version: 66871daeb12123ece012a9628d2798d01195c4b3
   subpackages:
   - base58
   - hdkeychain
 - name: github.com/btcsuite/fastsha256
   version: 637e656429416087660c84436a2a035d69d54e2e
-- name: github.com/btcsuite/golangcrypto
-  version: 53f62d9b43e87a6c56975cf862af7edf33a8d0df
-  subpackages:
-  - ripemd160
+- name: github.com/ethanfrey/ledger
+  version: 5e432577be582bd18a3b4a9cd75dae7a317ade36
+- name: github.com/flynn/hid
+  version: ed06a31c6245d4552e8dbba7e32e5b010b875d65
 - name: github.com/go-kit/kit
   version: d67bb4c202e3b91377d1079b110a6c9ce23ab2f8
   subpackages:
@@ -44,7 +44,7 @@ imports:
 - name: github.com/gorilla/mux
   version: bcd8bc72b08df0f70df986b97f95590779502d31
 - name: github.com/howeyc/crc16
-  version: 96a97a1abb579c7ff1a8ffa77f2e72d1c314b57f
+  version: 58da63c846043d0bea709c8d47039df06577d6d9
 - name: github.com/kr/logfmt
   version: b84e30acd515aadc4b783ad4ff83aff3299bdfe0
 - name: github.com/pkg/errors
@@ -59,12 +59,12 @@ imports:
   - edwards25519
   - extra25519
 - name: github.com/tendermint/go-wire
-  version: 5f88da3dbc1a72844e6dfaf274ce87f851d488eb
+  version: 55ae61f1fc83cfaa57ab7d54250d7a1a2be0b83c
   subpackages:
   - data
   - data/base58
 - name: github.com/tendermint/tmlibs
-  version: bffe6744ec277d60f707ab442e25513617842f8e
+  version: 8e5266a9ef2527e68a1571f932db8228a331b556
   subpackages:
   - common
   - log
@@ -81,16 +81,14 @@ imports:
   - ripemd160
   - salsa20/salsa
 - name: gopkg.in/go-playground/validator.v9
-  version: d529ee1b0f30352444f507cc6cdac96bfd12decc
+  version: 6d8c18553ea1ac493d049edd6f102f52e618f085
 testImports:
+- name: github.com/cmars/basen
+  version: fe3947df716ebfda9847eb1b9a48f9592e06478c
 - name: github.com/davecgh/go-spew
   version: 6d212800a42e8ab5c146b8ace3490ee17e5225f9
   subpackages:
   - spew
-- name: github.com/FactomProject/basen
-  version: fe3947df716ebfda9847eb1b9a48f9592e06478c
-- name: github.com/FactomProject/btcutilecc
-  version: d3a63a5752ecf3fbc06bd97365da752111c263df
 - name: github.com/mndrix/btcutil
   version: d3a63a5752ecf3fbc06bd97365da752111c263df
 - name: github.com/pmezard/go-difflib
@@ -103,6 +101,6 @@ testImports:
   - assert
   - require
 - name: github.com/tyler-smith/go-bip32
-  version: 2c9cfd17756470a0b7c3e4b7954bae7d11035504
+  version: eb790af526c30f23a7c8b00a48e342f9d0bd6386
 - name: github.com/tyler-smith/go-bip39
   version: 8e7a99b3e716f36d3b080a9a70f9eb45abe4edcc
diff --git a/glide.yaml b/glide.yaml
index a99d3b63f..9f20ddefc 100644
--- a/glide.yaml
+++ b/glide.yaml
@@ -30,6 +30,7 @@ import:
 - package: github.com/spf13/viper
 - package: gopkg.in/go-playground/validator.v9
 - package: github.com/howeyc/crc16
+- package: github.com/ethanfrey/ledger
 testImport:
 - package: github.com/mndrix/btcutil
 - package: github.com/stretchr/testify
diff --git a/keys/cryptostore/encoder.go b/keys/cryptostore/encoder.go
index 251543b60..31f49c3f7 100644
--- a/keys/cryptostore/encoder.go
+++ b/keys/cryptostore/encoder.go
@@ -43,7 +43,8 @@ func (e secretbox) Decrypt(saltBytes []byte, encBytes []byte, passphrase string)
 	privKeyBytes := encBytes
 	// NOTE: Some keys weren't encrypted with a passphrase and hence we have the conditional
 	if passphrase != "" {
-		key, err := bcrypt.GenerateFromPassword(saltBytes, []byte(passphrase), 14) // TODO parameterize.  14 is good today (2016)
+		var key []byte
+		key, err = bcrypt.GenerateFromPassword(saltBytes, []byte(passphrase), 14) // TODO parameterize.  14 is good today (2016)
 		if err != nil {
 			return crypto.PrivKey{}, errors.Wrap(err, "Invalid Passphrase")
 		}
@@ -55,7 +56,7 @@ func (e secretbox) Decrypt(saltBytes []byte, encBytes []byte, passphrase string)
 	}
 	privKey, err = crypto.PrivKeyFromBytes(privKeyBytes)
 	if err != nil {
-		return crypto.PrivKey{}, errors.Wrap(err, "Couldn't get privKey from bytes")
+		return crypto.PrivKey{}, errors.Wrap(err, "Private Key")
 	}
 	return privKey, nil
 }
diff --git a/keys/cryptostore/encoder_test.go b/keys/cryptostore/encoder_test.go
index ce1118d20..614286a19 100644
--- a/keys/cryptostore/encoder_test.go
+++ b/keys/cryptostore/encoder_test.go
@@ -15,8 +15,10 @@ func TestNoopEncoder(t *testing.T) {
 	assert, require := assert.New(t), require.New(t)
 	noop := cryptostore.Noop
 
-	key := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
-	key2 := cryptostore.GenSecp256k1.Generate(cmn.RandBytes(16))
+	key, err := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
+	require.NoError(err)
+	key2, err := cryptostore.GenSecp256k1.Generate(cmn.RandBytes(16))
+	require.NoError(err)
 
 	_, b, err := noop.Encrypt(key, "encode")
 	require.Nil(err)
@@ -43,7 +45,8 @@ func TestSecretBox(t *testing.T) {
 	assert, require := assert.New(t), require.New(t)
 	enc := cryptostore.SecretBox
 
-	key := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
+	key, err := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
+	require.NoError(err)
 	pass := "some-special-secret"
 
 	s, b, err := enc.Encrypt(key, pass)
@@ -65,7 +68,8 @@ func TestSecretBoxNoPass(t *testing.T) {
 	assert, require := assert.New(t), require.New(t)
 	enc := cryptostore.SecretBox
 
-	key := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
+	key, rerr := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
+	require.NoError(rerr)
 
 	cases := []struct {
 		encode string
@@ -95,7 +99,7 @@ func TestSecretBoxNoPass(t *testing.T) {
 
 	// now let's make sure raw bytes also work...
 	b := key.Bytes()
-	pk, err := enc.Decrypt(nil, b, "")
-	require.Nil(err, "%+v", err)
+	pk, rerr := enc.Decrypt(nil, b, "")
+	require.NoError(rerr)
 	assert.Equal(key, pk)
 }
diff --git a/keys/cryptostore/generator.go b/keys/cryptostore/generator.go
index 1f162ec08..65cc8e58b 100644
--- a/keys/cryptostore/generator.go
+++ b/keys/cryptostore/generator.go
@@ -4,6 +4,7 @@ import (
 	"github.com/pkg/errors"
 
 	crypto "github.com/tendermint/go-crypto"
+	"github.com/tendermint/go-crypto/nano"
 )
 
 var (
@@ -11,46 +12,78 @@ var (
 	GenEd25519 Generator = GenFunc(genEd25519)
 	// GenSecp256k1 produces Secp256k1 private keys
 	GenSecp256k1 Generator = GenFunc(genSecp256)
+	// GenLedgerEd25519 used Ed25519 keys stored on nano ledger s with cosmos app
+	GenLedgerEd25519 Generator = GenFunc(genLedgerEd25519)
 )
 
 // Generator determines the type of private key the keystore creates
 type Generator interface {
-	Generate(secret []byte) crypto.PrivKey
+	Generate(secret []byte) (crypto.PrivKey, error)
 }
 
 // GenFunc is a helper to transform a function into a Generator
-type GenFunc func(secret []byte) crypto.PrivKey
+type GenFunc func(secret []byte) (crypto.PrivKey, error)
 
-func (f GenFunc) Generate(secret []byte) crypto.PrivKey {
+func (f GenFunc) Generate(secret []byte) (crypto.PrivKey, error) {
 	return f(secret)
 }
 
-func genEd25519(secret []byte) crypto.PrivKey {
-	return crypto.GenPrivKeyEd25519FromSecret(secret).Wrap()
+func genEd25519(secret []byte) (crypto.PrivKey, error) {
+	key := crypto.GenPrivKeyEd25519FromSecret(secret).Wrap()
+	return key, nil
 }
 
-func genSecp256(secret []byte) crypto.PrivKey {
-	return crypto.GenPrivKeySecp256k1FromSecret(secret).Wrap()
+func genSecp256(secret []byte) (crypto.PrivKey, error) {
+	key := crypto.GenPrivKeySecp256k1FromSecret(secret).Wrap()
+	return key, nil
 }
 
-func getGenerator(algo string) (Generator, error) {
+// secret is completely ignored for the ledger...
+// just for interface compatibility
+func genLedgerEd25519(secret []byte) (crypto.PrivKey, error) {
+	return nano.NewPrivKeyLedgerEd25519Ed25519()
+}
+
+type genInvalidByte struct {
+	typ byte
+}
+
+func (g genInvalidByte) Generate(secret []byte) (crypto.PrivKey, error) {
+	err := errors.Errorf("Cannot generate keys for algorithm: %X", g.typ)
+	return crypto.PrivKey{}, err
+}
+
+type genInvalidAlgo struct {
+	algo string
+}
+
+func (g genInvalidAlgo) Generate(secret []byte) (crypto.PrivKey, error) {
+	err := errors.Errorf("Cannot generate keys for algorithm: %s", g.algo)
+	return crypto.PrivKey{}, err
+}
+
+func getGenerator(algo string) Generator {
 	switch algo {
 	case crypto.NameEd25519:
-		return GenEd25519, nil
+		return GenEd25519
 	case crypto.NameSecp256k1:
-		return GenSecp256k1, nil
+		return GenSecp256k1
+	case nano.NameLedgerEd25519:
+		return GenLedgerEd25519
 	default:
-		return nil, errors.Errorf("Cannot generate keys for algorithm: %s", algo)
+		return genInvalidAlgo{algo}
 	}
 }
 
-func getGeneratorByType(typ byte) (Generator, error) {
+func getGeneratorByType(typ byte) Generator {
 	switch typ {
 	case crypto.TypeEd25519:
-		return GenEd25519, nil
+		return GenEd25519
 	case crypto.TypeSecp256k1:
-		return GenSecp256k1, nil
+		return GenSecp256k1
+	case nano.TypeLedgerEd25519:
+		return GenLedgerEd25519
 	default:
-		return nil, errors.Errorf("Cannot generate keys for algorithm: %X", typ)
+		return genInvalidByte{typ}
 	}
 }
diff --git a/keys/cryptostore/holder.go b/keys/cryptostore/holder.go
index cb8a2e149..923190c1b 100644
--- a/keys/cryptostore/holder.go
+++ b/keys/cryptostore/holder.go
@@ -33,14 +33,15 @@ var _ keys.Manager = Manager{}
 //
 // algo must be a supported go-crypto algorithm: ed25519, secp256k1
 func (s Manager) Create(name, passphrase, algo string) (keys.Info, string, error) {
-	gen, err := getGenerator(algo)
+	// 128-bits are the all the randomness we can make use of
+	secret := crypto.CRandBytes(16)
+	gen := getGenerator(algo)
+
+	key, err := gen.Generate(secret)
 	if err != nil {
 		return keys.Info{}, "", err
 	}
 
-	// 128-bits are the all the randomness we can make use of
-	secret := crypto.CRandBytes(16)
-	key := gen.Generate(secret)
 	err = s.es.Put(name, passphrase, key)
 	if err != nil {
 		return keys.Info{}, "", err
@@ -74,11 +75,11 @@ func (s Manager) Recover(name, passphrase, seedphrase string) (keys.Info, error)
 	l := len(secret)
 	secret, typ := secret[:l-1], secret[l-1]
 
-	gen, err := getGeneratorByType(typ)
+	gen := getGeneratorByType(typ)
+	key, err := gen.Generate(secret)
 	if err != nil {
 		return keys.Info{}, err
 	}
-	key := gen.Generate(secret)
 
 	// d00d, it worked!  create the bugger....
 	err = s.es.Put(name, passphrase, key)
diff --git a/keys/cryptostore/holder_test.go b/keys/cryptostore/holder_test.go
index a8fc90989..3709cc55d 100644
--- a/keys/cryptostore/holder_test.go
+++ b/keys/cryptostore/holder_test.go
@@ -1,6 +1,9 @@
 package cryptostore_test
 
 import (
+	"bytes"
+	"fmt"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -12,6 +15,7 @@ import (
 	"github.com/tendermint/go-crypto/keys"
 	"github.com/tendermint/go-crypto/keys/cryptostore"
 	"github.com/tendermint/go-crypto/keys/storage/memstorage"
+	"github.com/tendermint/go-crypto/nano"
 )
 
 // TestKeyManagement makes sure we can manipulate these keys well
@@ -84,65 +88,123 @@ func TestKeyManagement(t *testing.T) {
 
 // TestSignVerify does some detailed checks on how we sign and validate
 // signatures
-// func TestSignVerify(t *testing.T) {
-// 	assert, require := assert.New(t), require.New(t)
+func TestSignVerify(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
 
-// 	// make the storage with reasonable defaults
-// 	cstore := cryptostore.New(
-// 		cryptostore.GenSecp256k1,
-// 		cryptostore.SecretBox,
-// 		memstorage.New(),
-// 	)
+	// make the storage with reasonable defaults
+	cstore := cryptostore.New(
+		cryptostore.SecretBox,
+		memstorage.New(),
+		keys.MustLoadCodec("english"),
+	)
+	algo := crypto.NameSecp256k1
 
-// 	n1, n2 := "some dude", "a dudette"
-// 	p1, p2 := "1234", "foobar"
+	n1, n2 := "some dude", "a dudette"
+	p1, p2 := "1234", "foobar"
 
-// 	// create two users and get their info
-// 	err := cstore.Create(n1, p1)
-// 	require.Nil(err)
-// 	i1, err := cstore.Get(n1)
-// 	require.Nil(err)
+	// create two users and get their info
+	i1, _, err := cstore.Create(n1, p1, algo)
+	require.Nil(err)
 
-// 	err = cstore.Create(n2, p2)
-// 	require.Nil(err)
-// 	i2, err := cstore.Get(n2)
-// 	require.Nil(err)
+	i2, _, err := cstore.Create(n2, p2, algo)
+	require.Nil(err)
 
-// 	// let's try to sign some messages
-// 	d1 := []byte("my first message")
-// 	d2 := []byte("some other important info!")
+	// let's try to sign some messages
+	d1 := []byte("my first message")
+	d2 := []byte("some other important info!")
 
-// 	// try signing both data with both keys...
-// 	s11, err := cstore.Signature(n1, p1, d1)
-// 	require.Nil(err)
-// 	s12, err := cstore.Signature(n1, p1, d2)
-// 	require.Nil(err)
-// 	s21, err := cstore.Signature(n2, p2, d1)
-// 	require.Nil(err)
-// 	s22, err := cstore.Signature(n2, p2, d2)
-// 	require.Nil(err)
+	// try signing both data with both keys...
+	s11 := keys.NewMockSignable(d1)
+	err = cstore.Sign(n1, p1, s11)
+	require.Nil(err)
+	s12 := keys.NewMockSignable(d2)
+	err = cstore.Sign(n1, p1, s12)
+	require.Nil(err)
+	s21 := keys.NewMockSignable(d1)
+	err = cstore.Sign(n2, p2, s21)
+	require.Nil(err)
+	s22 := keys.NewMockSignable(d2)
+	err = cstore.Sign(n2, p2, s22)
+	require.Nil(err)
 
-// 	// let's try to validate and make sure it only works when everything is proper
-// 	keys := [][]byte{i1.PubKey, i2.PubKey}
-// 	data := [][]byte{d1, d2}
-// 	sigs := [][]byte{s11, s12, s21, s22}
+	// let's try to validate and make sure it only works when everything is proper
+	cases := []struct {
+		key   crypto.PubKey
+		data  []byte
+		sig   crypto.Signature
+		valid bool
+	}{
+		// proper matches
+		{i1.PubKey, d1, s11.Signature, true},
+		// change data, pubkey, or signature leads to fail
+		{i1.PubKey, d2, s11.Signature, false},
+		{i2.PubKey, d1, s11.Signature, false},
+		{i1.PubKey, d1, s21.Signature, false},
+		// make sure other successes
+		{i1.PubKey, d2, s12.Signature, true},
+		{i2.PubKey, d1, s21.Signature, true},
+		{i2.PubKey, d2, s22.Signature, true},
+	}
 
-// 	// loop over keys and data
-// 	for k := 0; k < 2; k++ {
-// 		for d := 0; d < 2; d++ {
-// 			// make sure only the proper sig works
-// 			good := 2*k + d
-// 			for s := 0; s < 4; s++ {
-// 				err = cstore.Verify(data[d], sigs[s], keys[k])
-// 				if s == good {
-// 					assert.Nil(err, "%+v", err)
-// 				} else {
-// 					assert.NotNil(err)
-// 				}
-// 			}
-// 		}
-// 	}
-// }
+	for i, tc := range cases {
+		valid := tc.key.VerifyBytes(tc.data, tc.sig)
+		assert.Equal(tc.valid, valid, "%d", i)
+	}
+}
+
+// TestSignWithLedger makes sure we have ledger compatibility with
+// the crypto store.
+//
+// This test will only succeed with a ledger attached to the computer
+// and the cosmos app open
+func TestSignWithLedger(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+	if os.Getenv("WITH_LEDGER") == "" {
+		t.Skip("Set WITH_LEDGER to run code on real ledger")
+	}
+
+	// make the storage with reasonable defaults
+	cstore := cryptostore.New(
+		cryptostore.SecretBox,
+		memstorage.New(),
+		keys.MustLoadCodec("english"),
+	)
+	n := "nano-s"
+	p := "hard2hack"
+
+	// create a nano user
+	c, _, err := cstore.Create(n, p, nano.NameLedgerEd25519)
+	require.Nil(err, "%+v", err)
+	assert.Equal(c.Name, n)
+	_, ok := c.PubKey.Unwrap().(nano.PubKeyLedgerEd25519)
+	require.True(ok)
+
+	// make sure we can get it back
+	info, err := cstore.Get(n)
+	require.Nil(err, "%+v", err)
+	assert.Equal(info.Name, n)
+	key := info.PubKey
+	require.False(key.Empty())
+	require.True(key.Equals(c.PubKey))
+
+	// let's try to sign some messages
+	d1 := []byte("welcome to cosmos")
+	d2 := []byte("please turn on the app")
+
+	// try signing both data with the ledger...
+	s1 := keys.NewMockSignable(d1)
+	err = cstore.Sign(n, p, s1)
+	require.Nil(err)
+	s2 := keys.NewMockSignable(d2)
+	err = cstore.Sign(n, p, s2)
+	require.Nil(err)
+
+	// now, let's check those signatures work
+	assert.True(key.VerifyBytes(d1, s1.Signature))
+	assert.True(key.VerifyBytes(d2, s2.Signature))
+	// and mismatched signatures don't
+	assert.False(key.VerifyBytes(d1, s2.Signature))
+}
 
 func assertPassword(assert *assert.Assertions, cstore cryptostore.Manager, name, pass, badpass string) {
 	err := cstore.Update(name, badpass, pass)
@@ -162,13 +224,15 @@ func TestImportUnencrypted(t *testing.T) {
 		keys.MustLoadCodec("english"),
 	)
 
-	key := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
+	key, err := cryptostore.GenEd25519.Generate(cmn.RandBytes(16))
+	require.NoError(err)
+
 	addr := key.PubKey().Address()
 	name := "john"
 	pass := "top-secret"
 
 	// import raw bytes
-	err := cstore.Import(name, pass, "", nil, key.Bytes())
+	err = cstore.Import(name, pass, "", nil, key.Bytes())
 	require.Nil(err, "%+v", err)
 
 	// make sure the address matches
@@ -256,45 +320,59 @@ func TestSeedPhrase(t *testing.T) {
 	assert.Equal(info.PubKey, newInfo.PubKey)
 }
 
-// func ExampleStore() {
-// 	// Select the encryption and storage for your cryptostore
-// 	cstore := cryptostore.New(
-// 		cryptostore.GenEd25519,
-// 		cryptostore.SecretBox,
-// 		// Note: use filestorage.New(dir) for real data
-// 		memstorage.New(),
-// 	)
+func ExampleNew() {
+	// Select the encryption and storage for your cryptostore
+	cstore := cryptostore.New(
+		cryptostore.SecretBox,
+		// Note: use filestorage.New(dir) for real data
+		memstorage.New(),
+		keys.MustLoadCodec("english"),
+	)
+	ed := crypto.NameEd25519
+	sec := crypto.NameSecp256k1
 
-// 	// Add keys and see they return in alphabetical order
-// 	cstore.Create("Bob", "friend")
-// 	cstore.Create("Alice", "secret")
-// 	cstore.Create("Carl", "mitm")
-// 	info, _ := cstore.List()
-// 	for _, i := range info {
-// 		fmt.Println(i.Name)
-// 	}
+	// Add keys and see they return in alphabetical order
+	bob, _, err := cstore.Create("Bob", "friend", ed)
+	if err != nil {
+		// this should never happen
+		fmt.Println(err)
+	} else {
+		// return info here just like in List
+		fmt.Println(bob.Name)
+	}
+	cstore.Create("Alice", "secret", sec)
+	cstore.Create("Carl", "mitm", ed)
+	info, _ := cstore.List()
+	for _, i := range info {
+		fmt.Println(i.Name)
+	}
 
-// 	// We need to use passphrase to generate a signature
-// 	tx := mock.NewSig([]byte("deadbeef"))
-// 	err := cstore.Sign("Bob", "friend", tx)
-// 	if err != nil {
-// 		fmt.Println("don't accept real passphrase")
-// 	}
+	// We need to use passphrase to generate a signature
+	tx := keys.NewMockSignable([]byte("deadbeef"))
+	err = cstore.Sign("Bob", "friend", tx)
+	if err != nil {
+		fmt.Println("don't accept real passphrase")
+	}
 
-// 	// and we can validate the signature with publically available info
-// 	binfo, _ := cstore.Get("Bob")
-// 	sigs, err := tx.Signers()
-// 	if err != nil {
-// 		fmt.Println("badly signed")
-// 	} else if bytes.Equal(sigs[0].Bytes(), binfo.PubKey.Bytes()) {
-// 		fmt.Println("signed by Bob")
-// 	} else {
-// 		fmt.Println("signed by someone else")
-// 	}
+	// and we can validate the signature with publically available info
+	binfo, _ := cstore.Get("Bob")
+	if !binfo.PubKey.Equals(bob.PubKey) {
+		fmt.Println("Get and Create return different keys")
+	}
 
-// 	// Output:
-// 	// Alice
-// 	// Bob
-// 	// Carl
-// 	// signed by Bob
-// }
+	sigs, err := tx.Signers()
+	if err != nil {
+		fmt.Println("badly signed")
+	} else if bytes.Equal(sigs[0].Bytes(), binfo.PubKey.Bytes()) {
+		fmt.Println("signed by Bob")
+	} else {
+		fmt.Println("signed by someone else")
+	}
+
+	// Output:
+	// Bob
+	// Alice
+	// Bob
+	// Carl
+	// signed by Bob
+}
diff --git a/keys/cryptostore/storage_test.go b/keys/cryptostore/storage_test.go
index 468435143..23931c294 100644
--- a/keys/cryptostore/storage_test.go
+++ b/keys/cryptostore/storage_test.go
@@ -14,7 +14,10 @@ import (
 func TestSortKeys(t *testing.T) {
 	assert := assert.New(t)
 
-	gen := func() crypto.PrivKey { return GenEd25519.Generate(cmn.RandBytes(16)) }
+	gen := func() crypto.PrivKey {
+		key, _ := GenEd25519.Generate(cmn.RandBytes(16))
+		return key
+	}
 	assert.NotEqual(gen(), gen())
 
 	// alphabetical order is n3, n1, n2
diff --git a/keys/server/README.md b/keys/server/README.md
deleted file mode 100644
index 032cf574e..000000000
--- a/keys/server/README.md
+++ /dev/null
@@ -1,13 +0,0 @@
-# Proxy Server
-
-This package provides all the functionality for a local http server, providing access to key management functionality (creating, listing, updating, and deleting keys).  This is a nice building block for larger apps, and the HTTP handlers here can be embedded in a larger server that does nice things like signing transactions and posting them to a tendermint chain (which requires domain-knowledge of the transactions types and out of scope of this generic app).
-
-## Key Management
-
-We expose a number of methods for safely managing your keychain. If you are embedding this in a larger server, you will typically want to mount all these paths under `/keys`.
-
-* `POST /` - provide a name and passphrase and create a brand new key
-* `GET /` - get a list of all available key names, along with their public key and address
-* `GET /{name}` - get public key and address for this named key
-* `PUT /{name}` - update the passphrase for the given key. requires you to correctly provide the current passphrase, as well as a new one.
-* `DELETE /{name}` - permanently delete this private key. requires you to correctly provide the current passphrase
diff --git a/keys/server/helpers.go b/keys/server/helpers.go
deleted file mode 100644
index 3fb947316..000000000
--- a/keys/server/helpers.go
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
-package server provides http handlers to construct a server server
-for key management, transaction signing, and query validation.
-
-Please read the README and godoc to see how to
-configure the server for your application.
-*/
-
-package server
-
-import (
-	"encoding/json"
-	"io/ioutil"
-	"net/http"
-
-	"github.com/tendermint/go-crypto/keys/server/types"
-	data "github.com/tendermint/go-wire/data"
-
-	"github.com/pkg/errors"
-)
-
-func readRequest(r *http.Request, o interface{}) error {
-	defer r.Body.Close()
-	data, err := ioutil.ReadAll(r.Body)
-	if err != nil {
-		return errors.Wrap(err, "Read Request")
-	}
-	err = json.Unmarshal(data, o)
-	if err != nil {
-		return errors.Wrap(err, "Parse")
-	}
-	return validate(o)
-}
-
-// most errors are bad input, so 406... do better....
-func writeError(w http.ResponseWriter, err error) {
-	// fmt.Printf("Error: %+v\n", err)
-	res := types.ErrorResponse{
-		Code:  406,
-		Error: err.Error(),
-	}
-	writeCode(w, &res, 406)
-}
-
-func writeCode(w http.ResponseWriter, o interface{}, code int) {
-	// two space indent to make it easier to read
-	data, err := data.ToJSON(o)
-	if err != nil {
-		writeError(w, err)
-	} else {
-		w.Header().Set("Content-Type", "application/json")
-		w.WriteHeader(code)
-		w.Write(data)
-	}
-}
-
-func writeSuccess(w http.ResponseWriter, o interface{}) {
-	writeCode(w, o, 200)
-}
diff --git a/keys/server/keys.go b/keys/server/keys.go
deleted file mode 100644
index 80852802e..000000000
--- a/keys/server/keys.go
+++ /dev/null
@@ -1,128 +0,0 @@
-package server
-
-import (
-	"errors"
-	"net/http"
-
-	"github.com/gorilla/mux"
-	keys "github.com/tendermint/go-crypto/keys"
-	"github.com/tendermint/go-crypto/keys/server/types"
-)
-
-type Keys struct {
-	manager keys.Manager
-	algo    string
-}
-
-func New(manager keys.Manager, algo string) Keys {
-	return Keys{
-		manager: manager,
-		algo:    algo,
-	}
-}
-
-func (k Keys) GenerateKey(w http.ResponseWriter, r *http.Request) {
-	req := types.CreateKeyRequest{
-		Algo: k.algo, // default key type from cli
-	}
-	err := readRequest(r, &req)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-
-	key, seed, err := k.manager.Create(req.Name, req.Passphrase, req.Algo)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-
-	res := types.CreateKeyResponse{key, seed}
-	writeSuccess(w, &res)
-}
-
-func (k Keys) GetKey(w http.ResponseWriter, r *http.Request) {
-	vars := mux.Vars(r)
-	name := vars["name"]
-	key, err := k.manager.Get(name)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-	writeSuccess(w, &key)
-}
-
-func (k Keys) ListKeys(w http.ResponseWriter, r *http.Request) {
-
-	keys, err := k.manager.List()
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-	writeSuccess(w, keys)
-}
-
-func (k Keys) UpdateKey(w http.ResponseWriter, r *http.Request) {
-	req := types.UpdateKeyRequest{}
-	err := readRequest(r, &req)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-
-	vars := mux.Vars(r)
-	name := vars["name"]
-	if name != req.Name {
-		writeError(w, errors.New("path and json key names don't match"))
-		return
-	}
-
-	err = k.manager.Update(req.Name, req.OldPass, req.NewPass)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-
-	key, err := k.manager.Get(req.Name)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-	writeSuccess(w, &key)
-}
-
-func (k Keys) DeleteKey(w http.ResponseWriter, r *http.Request) {
-	req := types.DeleteKeyRequest{}
-	err := readRequest(r, &req)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-
-	vars := mux.Vars(r)
-	name := vars["name"]
-	if name != req.Name {
-		writeError(w, errors.New("path and json key names don't match"))
-		return
-	}
-
-	err = k.manager.Delete(req.Name, req.Passphrase)
-	if err != nil {
-		writeError(w, err)
-		return
-	}
-
-	// not really an error, but something generic
-	resp := types.ErrorResponse{
-		Success: true,
-	}
-	writeSuccess(w, &resp)
-}
-
-func (k Keys) Register(r *mux.Router) {
-	r.HandleFunc("/", k.GenerateKey).Methods("POST")
-	r.HandleFunc("/", k.ListKeys).Methods("GET")
-	r.HandleFunc("/{name}", k.GetKey).Methods("GET")
-	r.HandleFunc("/{name}", k.UpdateKey).Methods("POST", "PUT")
-	r.HandleFunc("/{name}", k.DeleteKey).Methods("DELETE")
-}
diff --git a/keys/server/keys_test.go b/keys/server/keys_test.go
deleted file mode 100644
index 2aa17753c..000000000
--- a/keys/server/keys_test.go
+++ /dev/null
@@ -1,193 +0,0 @@
-package server_test
-
-import (
-	"bytes"
-	"encoding/json"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-
-	"github.com/gorilla/mux"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	keys "github.com/tendermint/go-crypto/keys"
-	"github.com/tendermint/go-crypto/keys/cryptostore"
-	"github.com/tendermint/go-crypto/keys/server"
-	"github.com/tendermint/go-crypto/keys/server/types"
-	"github.com/tendermint/go-crypto/keys/storage/memstorage"
-)
-
-func TestKeyServer(t *testing.T) {
-	assert, require := assert.New(t), require.New(t)
-	r := setupServer()
-
-	// let's abstract this out a bit....
-	keys, code, err := listKeys(r)
-	require.Nil(err)
-	require.Equal(http.StatusOK, code)
-	assert.Equal(0, len(keys))
-
-	algo := "ed25519"
-	n1, n2 := "personal", "business"
-	p0, p1, p2 := "1234", "over10chars...", "really-secure!@#$"
-
-	// this fails for validation
-	_, code, err = createKey(r, n1, p0, algo)
-	require.Nil(err, "%+v", err)
-	require.NotEqual(http.StatusOK, code)
-
-	// new password better
-	key, code, err := createKey(r, n1, p1, algo)
-	require.Nil(err, "%+v", err)
-	require.Equal(http.StatusOK, code)
-	require.Equal(n1, key.Key.Name)
-	require.NotEmpty(n1, key.Seed)
-
-	// the other one works
-	key2, code, err := createKey(r, n2, p2, algo)
-	require.Nil(err, "%+v", err)
-	require.Equal(http.StatusOK, code)
-	require.Equal(key2.Key.Name, n2)
-	require.NotEmpty(n2, key.Seed)
-
-	// let's abstract this out a bit....
-	keys, code, err = listKeys(r)
-	require.Nil(err)
-	require.Equal(http.StatusOK, code)
-	if assert.Equal(2, len(keys)) {
-		// in alphabetical order
-		assert.Equal(keys[0].Name, n2)
-		assert.Equal(keys[1].Name, n1)
-	}
-
-	// get works
-	k, code, err := getKey(r, n1)
-	require.Nil(err, "%+v", err)
-	require.Equal(http.StatusOK, code)
-	assert.Equal(n1, k.Name)
-	assert.NotNil(k.Address)
-	assert.Equal(key.Key.Address, k.Address)
-
-	// delete with proper key
-	_, code, err = deleteKey(r, n1, p1)
-	require.Nil(err, "%+v", err)
-	require.Equal(http.StatusOK, code)
-
-	// after delete, get and list different
-	_, code, err = getKey(r, n1)
-	require.Nil(err, "%+v", err)
-	require.NotEqual(http.StatusOK, code)
-	keys, code, err = listKeys(r)
-	require.Nil(err, "%+v", err)
-	require.Equal(http.StatusOK, code)
-	if assert.Equal(1, len(keys)) {
-		assert.Equal(keys[0].Name, n2)
-	}
-
-}
-
-func setupServer() http.Handler {
-	// make the storage with reasonable defaults
-	cstore := cryptostore.New(
-		cryptostore.SecretBox,
-		memstorage.New(),
-		keys.MustLoadCodec("english"),
-	)
-
-	// build your http server
-	ks := server.New(cstore, "ed25519")
-	r := mux.NewRouter()
-	sk := r.PathPrefix("/keys").Subrouter()
-	ks.Register(sk)
-	return r
-}
-
-// return data, status code, and error
-func listKeys(h http.Handler) (keys.Infos, int, error) {
-	rr := httptest.NewRecorder()
-	req, err := http.NewRequest("GET", "/keys/", nil)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	h.ServeHTTP(rr, req)
-	if http.StatusOK != rr.Code {
-		return nil, rr.Code, nil
-	}
-
-	data := keys.Infos{}
-	err = json.Unmarshal(rr.Body.Bytes(), &data)
-	return data, rr.Code, err
-}
-
-func getKey(h http.Handler, name string) (*keys.Info, int, error) {
-	rr := httptest.NewRecorder()
-	req, err := http.NewRequest("GET", "/keys/"+name, nil)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	h.ServeHTTP(rr, req)
-	if http.StatusOK != rr.Code {
-		return nil, rr.Code, nil
-	}
-
-	data := keys.Info{}
-	err = json.Unmarshal(rr.Body.Bytes(), &data)
-	return &data, rr.Code, err
-}
-
-func createKey(h http.Handler, name, passphrase, algo string) (*types.CreateKeyResponse, int, error) {
-	rr := httptest.NewRecorder()
-	post := types.CreateKeyRequest{
-		Name:       name,
-		Passphrase: passphrase,
-		Algo:       algo,
-	}
-	var b bytes.Buffer
-	err := json.NewEncoder(&b).Encode(&post)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	req, err := http.NewRequest("POST", "/keys/", &b)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	h.ServeHTTP(rr, req)
-	if http.StatusOK != rr.Code {
-		return nil, rr.Code, nil
-	}
-
-	data := new(types.CreateKeyResponse)
-	err = json.Unmarshal(rr.Body.Bytes(), data)
-	return data, rr.Code, err
-}
-
-func deleteKey(h http.Handler, name, passphrase string) (*types.ErrorResponse, int, error) {
-	rr := httptest.NewRecorder()
-	post := types.DeleteKeyRequest{
-		Name:       name,
-		Passphrase: passphrase,
-	}
-	var b bytes.Buffer
-	err := json.NewEncoder(&b).Encode(&post)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	req, err := http.NewRequest("DELETE", "/keys/"+name, &b)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	h.ServeHTTP(rr, req)
-	if http.StatusOK != rr.Code {
-		return nil, rr.Code, nil
-	}
-
-	data := types.ErrorResponse{}
-	err = json.Unmarshal(rr.Body.Bytes(), &data)
-	return &data, rr.Code, err
-}
diff --git a/keys/server/types/keys.go b/keys/server/types/keys.go
deleted file mode 100644
index 56ed60ceb..000000000
--- a/keys/server/types/keys.go
+++ /dev/null
@@ -1,35 +0,0 @@
-package types
-
-import "github.com/tendermint/go-crypto/keys"
-
-// CreateKeyRequest is sent to create a new key
-type CreateKeyRequest struct {
-	Name       string `json:"name" validate:"required,min=4,printascii"`
-	Passphrase string `json:"passphrase" validate:"required,min=10"`
-	Algo       string `json:"algo"`
-}
-
-// DeleteKeyRequest to destroy a key permanently (careful!)
-type DeleteKeyRequest struct {
-	Name       string `json:"name" validate:"required,min=4,printascii"`
-	Passphrase string `json:"passphrase" validate:"required,min=10"`
-}
-
-// UpdateKeyRequest is sent to update the passphrase for an existing key
-type UpdateKeyRequest struct {
-	Name    string `json:"name" validate:"required,min=4,printascii"`
-	OldPass string `json:"passphrase"  validate:"required,min=10"`
-	NewPass string `json:"new_passphrase" validate:"required,min=10"`
-}
-
-// ErrorResponse is returned for 4xx and 5xx errors
-type ErrorResponse struct {
-	Success bool   `json:"success"`
-	Error   string `json:"error"` // error message if Success is false
-	Code    int    `json:"code"`  // error code if Success is false
-}
-
-type CreateKeyResponse struct {
-	Key  keys.Info `json:"key"`
-	Seed string    `json:"seed_phrase"`
-}
diff --git a/keys/server/valid.go b/keys/server/valid.go
deleted file mode 100644
index 50b51e21b..000000000
--- a/keys/server/valid.go
+++ /dev/null
@@ -1,12 +0,0 @@
-package server
-
-import (
-	"github.com/pkg/errors"
-	"gopkg.in/go-playground/validator.v9"
-)
-
-var v = validator.New()
-
-func validate(req interface{}) error {
-	return errors.Wrap(v.Struct(req), "Validate")
-}
diff --git a/keys/transactions.go b/keys/transactions.go
index 10da7a6fa..1834ada26 100644
--- a/keys/transactions.go
+++ b/keys/transactions.go
@@ -1,9 +1,11 @@
 package keys
 
 import (
+	"fmt"
 	"sort"
 
 	crypto "github.com/tendermint/go-crypto"
+	wire "github.com/tendermint/go-wire"
 	data "github.com/tendermint/go-wire/data"
 )
 
@@ -72,3 +74,52 @@ type Manager interface {
 	Update(name, oldpass, newpass string) error
 	Delete(name, passphrase string) error
 }
+
+/**** MockSignable allows us to view data ***/
+
+// MockSignable lets us wrap arbitrary data with a go-crypto signature
+type MockSignable struct {
+	Data      []byte
+	PubKey    crypto.PubKey
+	Signature crypto.Signature
+}
+
+var _ Signable = &MockSignable{}
+
+// NewMockSignable sets the data to sign
+func NewMockSignable(data []byte) *MockSignable {
+	return &MockSignable{Data: data}
+}
+
+// TxBytes returns the full data with signatures
+func (s *MockSignable) TxBytes() ([]byte, error) {
+	return wire.BinaryBytes(s), nil
+}
+
+// SignBytes returns the original data passed into `NewSig`
+func (s *MockSignable) SignBytes() []byte {
+	return s.Data
+}
+
+// Sign will add a signature and pubkey.
+//
+// Depending on the Signable, one may be able to call this multiple times for multisig
+// Returns error if called with invalid data or too many times
+func (s *MockSignable) Sign(pubkey crypto.PubKey, sig crypto.Signature) error {
+	s.PubKey = pubkey
+	s.Signature = sig
+	return nil
+}
+
+// Signers will return the public key(s) that signed if the signature
+// is valid, or an error if there is any issue with the signature,
+// including if there are no signatures
+func (s *MockSignable) Signers() ([]crypto.PubKey, error) {
+	if s.PubKey.Empty() {
+		return nil, fmt.Errorf("no signers")
+	}
+	if !s.PubKey.VerifyBytes(s.SignBytes(), s.Signature) {
+		return nil, fmt.Errorf("invalid signature")
+	}
+	return []crypto.PubKey{s.PubKey}, nil
+}
diff --git a/nano/keys.go b/nano/keys.go
new file mode 100644
index 000000000..a6d3ea8e4
--- /dev/null
+++ b/nano/keys.go
@@ -0,0 +1,294 @@
+package nano
+
+import (
+	"bytes"
+	"encoding/hex"
+
+	"github.com/pkg/errors"
+
+	ledger "github.com/ethanfrey/ledger"
+
+	crypto "github.com/tendermint/go-crypto"
+	wire "github.com/tendermint/go-wire"
+)
+
+//nolint
+const (
+	NameLedgerEd25519 = "ledger-ed25519"
+	TypeLedgerEd25519 = 0x10
+
+	// Timeout is the number of seconds to wait for a response from the ledger
+	// if eg. waiting for user confirmation on button push
+	Timeout = 20
+)
+
+var device *ledger.Ledger
+
+// getLedger gets a copy of the device, and caches it
+func getLedger() (*ledger.Ledger, error) {
+	var err error
+	if device == nil {
+		device, err = ledger.FindLedger()
+	}
+	return device, err
+}
+
+func signLedger(device *ledger.Ledger, msg []byte) (pk crypto.PubKey, sig crypto.Signature, err error) {
+	var resp []byte
+
+	packets := generateSignRequests(msg)
+	for _, pack := range packets {
+		resp, err = device.Exchange(pack, Timeout)
+		if err != nil {
+			return pk, sig, err
+		}
+	}
+
+	// the last call is the result we want and needs to be parsed
+	key, bsig, err := parseDigest(resp)
+	if err != nil {
+		return pk, sig, err
+	}
+
+	var b [32]byte
+	copy(b[:], key)
+	return PubKeyLedgerEd25519FromBytes(b), crypto.SignatureEd25519FromBytes(bsig), nil
+}
+
+// PrivKeyLedgerEd25519 implements PrivKey, calling the ledger nano
+// we cache the PubKey from the first call to use it later
+type PrivKeyLedgerEd25519 struct {
+	// PubKey should be private, but we want to encode it via go-wire
+	// so we can view the address later, even without having the ledger
+	// attached
+	CachedPubKey crypto.PubKey
+}
+
+// NewPrivKeyLedgerEd25519Ed25519 will generate a new key and store the
+// public key for later use.
+func NewPrivKeyLedgerEd25519Ed25519() (crypto.PrivKey, error) {
+	var pk PrivKeyLedgerEd25519
+	// getPubKey will cache the pubkey for later use,
+	// this allows us to return an error early if the ledger
+	// is not plugged in
+	_, err := pk.getPubKey()
+	return pk.Wrap(), err
+}
+
+// ValidateKey allows us to verify the sanity of a key
+// after loading it from disk
+func (pk *PrivKeyLedgerEd25519) ValidateKey() error {
+	// getPubKey will return an error if the ledger is not
+	// properly set up...
+	pub, err := pk.forceGetPubKey()
+	if err != nil {
+		return err
+	}
+	// verify this matches cached address
+	if !pub.Equals(pk.CachedPubKey) {
+		return errors.New("ledger doesn't match cached key")
+	}
+	return nil
+}
+
+// AssertIsPrivKeyInner fulfils PrivKey Interface
+func (pk *PrivKeyLedgerEd25519) AssertIsPrivKeyInner() {}
+
+// Bytes fulfils pk Interface - stores the cached pubkey so we can verify
+// the same key when we reconnect to a ledger
+func (pk *PrivKeyLedgerEd25519) Bytes() []byte {
+	return wire.BinaryBytes(pk.Wrap())
+}
+
+// Sign calls the ledger and stores the pk for future use
+//
+// XXX/TODO: panics if there is an error communicating with the ledger.
+//
+// Communication is checked on NewPrivKeyLedger and PrivKeyFromBytes,
+// returning an error, so this should only trigger if the privkey is held
+// in memory for a while before use.
+func (pk *PrivKeyLedgerEd25519) Sign(msg []byte) crypto.Signature {
+	// oh, I wish there was better error handling
+	dev, err := getLedger()
+	if err != nil {
+		panic(err)
+	}
+
+	pub, sig, err := signLedger(dev, msg)
+	if err != nil {
+		panic(err)
+	}
+
+	// if we have no pubkey yet, store it for future queries
+	if pk.CachedPubKey.Empty() {
+		pk.CachedPubKey = pub
+	} else if !pk.CachedPubKey.Equals(pub) {
+		panic("signed with a different key than stored")
+	}
+	return sig
+}
+
+// PubKey returns the stored PubKey
+// TODO: query the ledger if not there, once it is not volatile
+func (pk *PrivKeyLedgerEd25519) PubKey() crypto.PubKey {
+	key, err := pk.getPubKey()
+	if err != nil {
+		panic(err)
+	}
+	return key
+}
+
+// getPubKey reads the pubkey from cache or from the ledger itself
+// since this involves IO, it may return an error, which is not exposed
+// in the PubKey interface, so this function allows better error handling
+func (pk *PrivKeyLedgerEd25519) getPubKey() (key crypto.PubKey, err error) {
+	// if we have no pubkey, set it
+	if pk.CachedPubKey.Empty() {
+		pk.CachedPubKey, err = pk.forceGetPubKey()
+	}
+	return pk.CachedPubKey, err
+}
+
+// forceGetPubKey is like getPubKey but ignores any cached key
+// and ensures we get it from the ledger itself.
+func (pk *PrivKeyLedgerEd25519) forceGetPubKey() (key crypto.PubKey, err error) {
+	dev, err := getLedger()
+	if err != nil {
+		return key, errors.New("Can't connect to ledger device")
+	}
+	key, _, err = signLedger(dev, []byte{0})
+	if err != nil {
+		return key, errors.New("Please open cosmos app on the ledger")
+	}
+	return key, err
+}
+
+// Equals fulfils PrivKey Interface - makes sure both keys refer to the
+// same
+func (pk *PrivKeyLedgerEd25519) Equals(other crypto.PrivKey) bool {
+	if ledger, ok := other.Unwrap().(*PrivKeyLedgerEd25519); ok {
+		return pk.CachedPubKey.Equals(ledger.CachedPubKey)
+	}
+	return false
+}
+
+// MockPrivKeyLedgerEd25519 behaves as the ledger, but stores a pre-packaged call-response
+// for use in test cases
+type MockPrivKeyLedgerEd25519 struct {
+	Msg []byte
+	Pub [KeyLength]byte
+	Sig [SigLength]byte
+}
+
+// NewMockKey returns
+func NewMockKey(msg, pubkey, sig string) (pk MockPrivKeyLedgerEd25519) {
+	var err error
+	pk.Msg, err = hex.DecodeString(msg)
+	if err != nil {
+		panic(err)
+	}
+
+	bpk, err := hex.DecodeString(pubkey)
+	if err != nil {
+		panic(err)
+	}
+	bsig, err := hex.DecodeString(sig)
+	if err != nil {
+		panic(err)
+	}
+
+	copy(pk.Pub[:], bpk)
+	copy(pk.Sig[:], bsig)
+	return pk
+}
+
+var _ crypto.PrivKeyInner = MockPrivKeyLedgerEd25519{}
+
+// AssertIsPrivKeyInner fulfils PrivKey Interface
+func (pk MockPrivKeyLedgerEd25519) AssertIsPrivKeyInner() {}
+
+// Bytes fulfils PrivKey Interface - not supported
+func (pk MockPrivKeyLedgerEd25519) Bytes() []byte {
+	return nil
+}
+
+// Sign returns a real SignatureLedger, if the msg matches what we expect
+func (pk MockPrivKeyLedgerEd25519) Sign(msg []byte) crypto.Signature {
+	if !bytes.Equal(pk.Msg, msg) {
+		panic("Mock key is for different msg")
+	}
+	return crypto.SignatureEd25519(pk.Sig).Wrap()
+}
+
+// PubKey returns a real PubKeyLedgerEd25519, that will verify this signature
+func (pk MockPrivKeyLedgerEd25519) PubKey() crypto.PubKey {
+	return PubKeyLedgerEd25519FromBytes(pk.Pub)
+}
+
+// Equals compares that two Mocks have the same data
+func (pk MockPrivKeyLedgerEd25519) Equals(other crypto.PrivKey) bool {
+	if mock, ok := other.Unwrap().(MockPrivKeyLedgerEd25519); ok {
+		return bytes.Equal(mock.Pub[:], pk.Pub[:]) &&
+			bytes.Equal(mock.Sig[:], pk.Sig[:]) &&
+			bytes.Equal(mock.Msg, pk.Msg)
+	}
+	return false
+}
+
+////////////////////////////////////////////
+// pubkey
+
+// PubKeyLedgerEd25519 works like a normal Ed25519 except a hash before the verify bytes
+type PubKeyLedgerEd25519 struct {
+	crypto.PubKeyEd25519
+}
+
+// PubKeyLedgerEd25519FromBytes creates a PubKey from the raw bytes
+func PubKeyLedgerEd25519FromBytes(key [32]byte) crypto.PubKey {
+	return PubKeyLedgerEd25519{crypto.PubKeyEd25519(key)}.Wrap()
+}
+
+// Bytes fulfils pk Interface - no data, just type info
+func (pk PubKeyLedgerEd25519) Bytes() []byte {
+	return wire.BinaryBytes(pk.Wrap())
+}
+
+// VerifyBytes uses the normal Ed25519 algorithm but a sha512 hash beforehand
+func (pk PubKeyLedgerEd25519) VerifyBytes(msg []byte, sig crypto.Signature) bool {
+	hmsg := hashMsg(msg)
+	return pk.PubKeyEd25519.VerifyBytes(hmsg, sig)
+}
+
+// Equals implements PubKey interface
+func (pk PubKeyLedgerEd25519) Equals(other crypto.PubKey) bool {
+	if ledger, ok := other.Unwrap().(PubKeyLedgerEd25519); ok {
+		return pk.PubKeyEd25519.Equals(ledger.PubKeyEd25519.Wrap())
+	}
+	return false
+}
+
+/*** registration with go-data ***/
+
+func init() {
+	crypto.PrivKeyMapper.
+		RegisterImplementation(&PrivKeyLedgerEd25519{}, NameLedgerEd25519, TypeLedgerEd25519).
+		RegisterImplementation(MockPrivKeyLedgerEd25519{}, "mock-ledger", 0x11)
+
+	crypto.PubKeyMapper.
+		RegisterImplementation(PubKeyLedgerEd25519{}, NameLedgerEd25519, TypeLedgerEd25519)
+}
+
+// Wrap fulfils interface for PrivKey struct
+func (pk *PrivKeyLedgerEd25519) Wrap() crypto.PrivKey {
+	return crypto.PrivKey{PrivKeyInner: pk}
+}
+
+// Wrap fulfils interface for PrivKey struct
+func (pk MockPrivKeyLedgerEd25519) Wrap() crypto.PrivKey {
+	return crypto.PrivKey{PrivKeyInner: pk}
+}
+
+// Wrap fulfils interface for PubKey struct
+func (pk PubKeyLedgerEd25519) Wrap() crypto.PubKey {
+	return crypto.PubKey{PubKeyInner: pk}
+}
diff --git a/nano/keys_test.go b/nano/keys_test.go
new file mode 100644
index 000000000..15aa0d545
--- /dev/null
+++ b/nano/keys_test.go
@@ -0,0 +1,142 @@
+package nano
+
+import (
+	"encoding/hex"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	crypto "github.com/tendermint/go-crypto"
+)
+
+func TestLedgerKeys(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	cases := []struct {
+		msg, pubkey, sig string
+		valid            bool
+	}{
+		0: {
+			msg:    "F00D",
+			pubkey: "8E8754F012C2FDB492183D41437FD837CB81D8BBE731924E2E0DAF43FD3F2C93",
+			sig:    "787DC03E9E4EE05983E30BAE0DEFB8DB0671DBC2F5874AC93F8D8CA4018F7A42D6F9A9BCEADB422AC8E27CEE9CA205A0B88D22CD686F0A43EB806E8190A3C400",
+			valid:  true,
+		},
+		1: {
+			msg:    "DEADBEEF",
+			pubkey: "0C45ADC887A5463F668533443C829ED13EA8E2E890C778957DC28DB9D2AD5A6C",
+			sig:    "00ED74EED8FDAC7988A14BF6BC222120CBAC249D569AF4C2ADABFC86B792F97DF73C4919BE4B6B0ACB53547273BF29FBF0A9E0992FFAB6CB6C9B09311FC86A00",
+			valid:  true,
+		},
+		2: {
+			msg:    "1234567890AA",
+			pubkey: "598FC1F0C76363D14D7480736DEEF390D85863360F075792A6975EFA149FD7EA",
+			sig:    "59AAB7D7BDC4F936B6415DE672A8B77FA6B8B3451CD95B3A631F31F9A05DAEEE5E7E4F89B64DDEBB5F63DC042CA13B8FCB8185F82AD7FD5636FFDA6B0DC9570B",
+			valid:  true,
+		},
+		3: {
+			msg:    "1234432112344321",
+			pubkey: "359E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:    "616B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid:  true,
+		},
+		4: {
+			msg:    "12344321123443",
+			pubkey: "359E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:    "616B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid:  false,
+		},
+		5: {
+			msg:    "1234432112344321",
+			pubkey: "459E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:    "616B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid:  false,
+		},
+		6: {
+			msg:    "1234432112344321",
+			pubkey: "359E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:    "716B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid:  false,
+		},
+	}
+
+	for i, tc := range cases {
+		bmsg, err := hex.DecodeString(tc.msg)
+		require.NoError(err, "%d", i)
+
+		priv := NewMockKey(tc.msg, tc.pubkey, tc.sig)
+		pub := priv.PubKey()
+		sig := priv.Sign(bmsg)
+
+		valid := pub.VerifyBytes(bmsg, sig)
+		assert.Equal(tc.valid, valid, "%d", i)
+	}
+}
+
+func TestRealLedger(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	if os.Getenv("WITH_LEDGER") == "" {
+		t.Skip("Set WITH_LEDGER to run code on real ledger")
+	}
+	msg := []byte("kuhehfeohg")
+
+	priv, err := NewPrivKeyLedgerEd25519Ed25519()
+	require.Nil(err, "%+v", err)
+	pub := priv.PubKey()
+	sig := priv.Sign(msg)
+
+	valid := pub.VerifyBytes(msg, sig)
+	assert.True(valid)
+
+	// now, let's serialize the key and make sure it still works
+	bs := priv.Bytes()
+	priv2, err := crypto.PrivKeyFromBytes(bs)
+	require.Nil(err, "%+v", err)
+
+	// make sure we get the same pubkey when we load from disk
+	pub2 := priv2.PubKey()
+	require.Equal(pub, pub2)
+
+	// signing with the loaded key should match the original pubkey
+	sig = priv2.Sign(msg)
+	valid = pub.VerifyBytes(msg, sig)
+	assert.True(valid)
+
+	// make sure pubkeys serialize properly as well
+	bs = pub.Bytes()
+	bpub, err := crypto.PubKeyFromBytes(bs)
+	require.NoError(err)
+	assert.Equal(pub, bpub)
+}
+
+// TestRealLedgerErrorHandling calls. These tests assume
+// the ledger is not plugged in....
+func TestRealLedgerErrorHandling(t *testing.T) {
+	require := require.New(t)
+
+	if os.Getenv("WITH_LEDGER") != "" {
+		t.Skip("Skipping on WITH_LEDGER as it tests unplugged cases")
+	}
+
+	// first, try to generate a key, must return an error
+	// (no panic)
+	_, err := NewPrivKeyLedgerEd25519Ed25519()
+	require.Error(err)
+
+	led := PrivKeyLedgerEd25519{} // empty
+	// or with some pub key
+	ed := crypto.GenPrivKeyEd25519()
+	led2 := PrivKeyLedgerEd25519{CachedPubKey: ed.PubKey()}
+
+	// loading these should return errors
+	bs := led.Bytes()
+	_, err = crypto.PrivKeyFromBytes(bs)
+	require.Error(err)
+
+	bs = led2.Bytes()
+	_, err = crypto.PrivKeyFromBytes(bs)
+	require.Error(err)
+}
diff --git a/nano/sign.go b/nano/sign.go
new file mode 100644
index 000000000..c40801583
--- /dev/null
+++ b/nano/sign.go
@@ -0,0 +1,63 @@
+package nano
+
+import (
+	"bytes"
+	"crypto/sha512"
+
+	"github.com/pkg/errors"
+)
+
+const (
+	App       = 0x80
+	Init      = 0x00
+	Update    = 0x01
+	Digest    = 0x02
+	MaxChunk  = 253
+	KeyLength = 32
+	SigLength = 64
+)
+
+var separator = []byte{0, 0xCA, 0xFE, 0}
+
+func generateSignRequests(payload []byte) [][]byte {
+	// nice one-shot
+	digest := []byte{App, Digest}
+	if len(payload) < MaxChunk {
+		return [][]byte{append(digest, payload...)}
+	}
+
+	// large payload is multi-chunk
+	result := [][]byte{{App, Init}}
+	update := []byte{App, Update}
+	for len(payload) > MaxChunk {
+		msg := append(update, payload[:MaxChunk]...)
+		payload = payload[MaxChunk:]
+		result = append(result, msg)
+	}
+	result = append(result, append(update, payload...))
+	result = append(result, digest)
+	return result
+}
+
+func parseDigest(resp []byte) (key, sig []byte, err error) {
+	if resp[0] != App || resp[1] != Digest {
+		return nil, nil, errors.New("Invalid header")
+	}
+	resp = resp[2:]
+	if len(resp) != KeyLength+SigLength+len(separator) {
+		return nil, nil, errors.Errorf("Incorrect length: %d", len(resp))
+	}
+
+	key, resp = resp[:KeyLength], resp[KeyLength:]
+	if !bytes.Equal(separator, resp[:len(separator)]) {
+		return nil, nil, errors.New("Cannot find 0xCAFE")
+	}
+
+	sig = resp[len(separator):]
+	return key, sig, nil
+}
+
+func hashMsg(data []byte) []byte {
+	res := sha512.Sum512(data)
+	return res[:]
+}
diff --git a/nano/sign_test.go b/nano/sign_test.go
new file mode 100644
index 000000000..04a6d0be7
--- /dev/null
+++ b/nano/sign_test.go
@@ -0,0 +1,159 @@
+package nano
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/pkg/errors"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	crypto "github.com/tendermint/go-crypto"
+)
+
+func parseEdKey(data []byte) (key crypto.PubKey, err error) {
+	ed := crypto.PubKeyEd25519{}
+	if len(data) < len(ed) {
+		return key, errors.Errorf("Key length too short: %d", len(data))
+	}
+	copy(ed[:], data)
+	return ed.Wrap(), nil
+}
+
+func parseSig(data []byte) (key crypto.Signature, err error) {
+	ed := crypto.SignatureEd25519{}
+	if len(data) < len(ed) {
+		return key, errors.Errorf("Sig length too short: %d", len(data))
+	}
+	copy(ed[:], data)
+	return ed.Wrap(), nil
+}
+
+func TestParseDigest(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	cases := []struct {
+		output string
+		key    string
+		sig    string
+		valid  bool
+	}{
+		{
+			output: "80028E8754F012C2FDB492183D41437FD837CB81D8BBE731924E2E0DAF43FD3F2C9300CAFE00787DC03E9E4EE05983E30BAE0DEFB8DB0671DBC2F5874AC93F8D8CA4018F7A42D6F9A9BCEADB422AC8E27CEE9CA205A0B88D22CD686F0A43EB806E8190A3C400",
+			key:    "8E8754F012C2FDB492183D41437FD837CB81D8BBE731924E2E0DAF43FD3F2C93",
+			sig:    "787DC03E9E4EE05983E30BAE0DEFB8DB0671DBC2F5874AC93F8D8CA4018F7A42D6F9A9BCEADB422AC8E27CEE9CA205A0B88D22CD686F0A43EB806E8190A3C400",
+			valid:  true,
+		},
+		{
+			output: "800235467890876543525437890796574535467890",
+			key:    "",
+			sig:    "",
+			valid:  false,
+		},
+	}
+
+	for i, tc := range cases {
+		msg, err := hex.DecodeString(tc.output)
+		require.Nil(err, "%d: %+v", i, err)
+
+		lKey, lSig, err := parseDigest(msg)
+		if !tc.valid {
+			assert.NotNil(err, "%d", i)
+		} else if assert.Nil(err, "%d: %+v", i, err) {
+			key, err := hex.DecodeString(tc.key)
+			require.Nil(err, "%d: %+v", i, err)
+			sig, err := hex.DecodeString(tc.sig)
+			require.Nil(err, "%d: %+v", i, err)
+
+			assert.Equal(key, lKey, "%d", i)
+			assert.Equal(sig, lSig, "%d", i)
+		}
+	}
+}
+
+type cryptoCase struct {
+	msg   string
+	key   string
+	sig   string
+	valid bool
+}
+
+func toBytes(c cryptoCase) (msg, key, sig []byte, err error) {
+	msg, err = hex.DecodeString(c.msg)
+	if err != nil {
+		return
+	}
+	key, err = hex.DecodeString(c.key)
+	if err != nil {
+		return
+	}
+	sig, err = hex.DecodeString(c.sig)
+	return
+}
+
+func TestCryptoConvert(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	cases := []cryptoCase{
+		0: {
+			msg:   "F00D",
+			key:   "8E8754F012C2FDB492183D41437FD837CB81D8BBE731924E2E0DAF43FD3F2C93",
+			sig:   "787DC03E9E4EE05983E30BAE0DEFB8DB0671DBC2F5874AC93F8D8CA4018F7A42D6F9A9BCEADB422AC8E27CEE9CA205A0B88D22CD686F0A43EB806E8190A3C400",
+			valid: true,
+		},
+		1: {
+			msg:   "DEADBEEF",
+			key:   "0C45ADC887A5463F668533443C829ED13EA8E2E890C778957DC28DB9D2AD5A6C",
+			sig:   "00ED74EED8FDAC7988A14BF6BC222120CBAC249D569AF4C2ADABFC86B792F97DF73C4919BE4B6B0ACB53547273BF29FBF0A9E0992FFAB6CB6C9B09311FC86A00",
+			valid: true,
+		},
+		2: {
+			msg:   "1234567890AA",
+			key:   "598FC1F0C76363D14D7480736DEEF390D85863360F075792A6975EFA149FD7EA",
+			sig:   "59AAB7D7BDC4F936B6415DE672A8B77FA6B8B3451CD95B3A631F31F9A05DAEEE5E7E4F89B64DDEBB5F63DC042CA13B8FCB8185F82AD7FD5636FFDA6B0DC9570B",
+			valid: true,
+		},
+		3: {
+			msg:   "1234432112344321",
+			key:   "359E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:   "616B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid: true,
+		},
+		4: {
+			msg:   "12344321123443",
+			key:   "359E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:   "616B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid: false,
+		},
+		5: {
+			msg:   "1234432112344321",
+			key:   "459E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:   "616B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid: false,
+		},
+		6: {
+			msg:   "1234432112344321",
+			key:   "359E0636E780457294CCA5D2D84DB190C3EDBD6879729C10D3963DEA1D5D8120",
+			sig:   "716B44EC7A65E7C719C170D669A47DE80C6AC0BB13FBCC89230976F9CC14D4CF9ECF26D4AFBB9FFF625599F1FF6F78EDA15E9F6B6BDCE07CFE9D8C407AC45208",
+			valid: false,
+		},
+	}
+
+	for i, tc := range cases {
+		msg, key, sig, err := toBytes(tc)
+		require.Nil(err, "%d: %+v", i, err)
+
+		pk, err := parseEdKey(key)
+		require.Nil(err, "%d: %+v", i, err)
+		psig, err := parseSig(sig)
+		require.Nil(err, "%d: %+v", i, err)
+
+		// it is not the signature of the message itself
+		valid := pk.VerifyBytes(msg, psig)
+		assert.False(valid, "%d", i)
+
+		// but rather of the hash of the msg
+		hmsg := hashMsg(msg)
+		valid = pk.VerifyBytes(hmsg, psig)
+		assert.Equal(tc.valid, valid, "%d", i)
+	}
+}
diff --git a/priv_key.go b/priv_key.go
index 0c6bd2ae7..e6e7ac036 100644
--- a/priv_key.go
+++ b/priv_key.go
@@ -13,13 +13,27 @@ import (
 
 func PrivKeyFromBytes(privKeyBytes []byte) (privKey PrivKey, err error) {
 	err = wire.ReadBinaryBytes(privKeyBytes, &privKey)
+	if err == nil {
+		// add support for a ValidateKey method on PrivKeys
+		// to make sure they load correctly
+		val, ok := privKey.Unwrap().(validatable)
+		if ok {
+			err = val.ValidateKey()
+		}
+	}
 	return
 }
 
+// validatable is an optional interface for keys that want to
+// check integrity
+type validatable interface {
+	ValidateKey() error
+}
+
 //----------------------------------------
 
 // DO NOT USE THIS INTERFACE.
-// You probably want to use PubKey
+// You probably want to use PrivKey
 // +gen wrapper:"PrivKey,Impl[PrivKeyEd25519,PrivKeySecp256k1],ed25519,secp256k1"
 type PrivKeyInner interface {
 	AssertIsPrivKeyInner()
diff --git a/priv_key_test.go b/priv_key_test.go
new file mode 100644
index 000000000..154df5593
--- /dev/null
+++ b/priv_key_test.go
@@ -0,0 +1,65 @@
+package crypto
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	wire "github.com/tendermint/go-wire"
+)
+
+type BadKey struct {
+	PrivKeyEd25519
+}
+
+// Wrap fulfils interface for PrivKey struct
+func (pk BadKey) Wrap() PrivKey {
+	return PrivKey{pk}
+}
+
+func (pk BadKey) Bytes() []byte {
+	return wire.BinaryBytes(pk.Wrap())
+}
+
+func (pk BadKey) ValidateKey() error {
+	return fmt.Errorf("fuggly key")
+}
+
+func init() {
+	PrivKeyMapper.
+		RegisterImplementation(BadKey{}, "bad", 0x66)
+}
+
+func TestReadPrivKey(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	// garbage in, garbage out
+	garbage := []byte("hjgewugfbiewgofwgewr")
+	_, err := PrivKeyFromBytes(garbage)
+	require.Error(err)
+
+	edKey := GenPrivKeyEd25519()
+	badKey := BadKey{edKey}
+
+	cases := []struct {
+		key   PrivKey
+		valid bool
+	}{
+		{edKey.Wrap(), true},
+		{badKey.Wrap(), false},
+	}
+
+	for i, tc := range cases {
+		data := tc.key.Bytes()
+		key, err := PrivKeyFromBytes(data)
+		if tc.valid {
+			assert.NoError(err, "%d", i)
+			assert.Equal(tc.key, key, "%d", i)
+		} else {
+			assert.Error(err, "%d: %#v", i, key)
+		}
+	}
+
+}
diff --git a/signature.go b/signature.go
index 5b1d6cb05..d2ea45132 100644
--- a/signature.go
+++ b/signature.go
@@ -63,6 +63,12 @@ func (sig *SignatureEd25519) UnmarshalJSON(enc []byte) error {
 	return err
 }
 
+func SignatureEd25519FromBytes(data []byte) Signature {
+	var sig SignatureEd25519
+	copy(sig[:], data)
+	return sig.Wrap()
+}
+
 //-------------------------------------
 
 var _ SignatureInner = SignatureSecp256k1{}