From 8c98c4fdf46aafc3b9d8690902ad38b8835a636a Mon Sep 17 00:00:00 2001
From: Ethan Frey <ethanfrey@users.noreply.github.com>
Date: Wed, 13 Sep 2017 12:41:54 +0200
Subject: [PATCH] Add nano ledger to key manager

---
 keys/cryptostore/generator.go | 18 ++++++++++++++++++
 nano/keys.go                  | 24 ++++++++++++++++--------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/keys/cryptostore/generator.go b/keys/cryptostore/generator.go
index 1f162ec08..c1984fc82 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 (
@@ -11,6 +12,8 @@ var (
 	GenEd25519 Generator = GenFunc(genEd25519)
 	// GenSecp256k1 produces Secp256k1 private keys
 	GenSecp256k1 Generator = GenFunc(genSecp256)
+	// GenLedger used Ed25519 keys stored on nano ledger s with cosmos app
+	GenLedger Generator = GenFunc(genLedger)
 )
 
 // Generator determines the type of private key the keystore creates
@@ -33,12 +36,25 @@ func genSecp256(secret []byte) crypto.PrivKey {
 	return crypto.GenPrivKeySecp256k1FromSecret(secret).Wrap()
 }
 
+// secret is completely ignored for the ledger...
+// just for interface compatibility
+func genLedger(secret []byte) crypto.PrivKey {
+	key, err := nano.NewPrivKeyLedger()
+	if err != nil {
+		// TODO: cleaner error handling
+		panic(err)
+	}
+	return key
+}
+
 func getGenerator(algo string) (Generator, error) {
 	switch algo {
 	case crypto.NameEd25519:
 		return GenEd25519, nil
 	case crypto.NameSecp256k1:
 		return GenSecp256k1, nil
+	case nano.NameLedger:
+		return GenLedger, nil
 	default:
 		return nil, errors.Errorf("Cannot generate keys for algorithm: %s", algo)
 	}
@@ -50,6 +66,8 @@ func getGeneratorByType(typ byte) (Generator, error) {
 		return GenEd25519, nil
 	case crypto.TypeSecp256k1:
 		return GenSecp256k1, nil
+	case nano.TypeLedger:
+		return GenLedger, nil
 	default:
 		return nil, errors.Errorf("Cannot generate keys for algorithm: %X", typ)
 	}
diff --git a/nano/keys.go b/nano/keys.go
index 6b337e8b7..2ab4d59a8 100644
--- a/nano/keys.go
+++ b/nano/keys.go
@@ -12,6 +12,11 @@ import (
 	wire "github.com/tendermint/go-wire"
 )
 
+const (
+	NameLedger = "ledger"
+	TypeLedger = 0x10
+)
+
 var device *ledger.Ledger
 
 // getLedger gets a copy of the device, and caches it
@@ -48,7 +53,10 @@ func signLedger(device *ledger.Ledger, msg []byte) (pk crypto.PubKey, sig crypto
 // PrivKeyLedger implements PrivKey, calling the ledger nano
 // we cache the PubKey from the first call to use it later
 type PrivKeyLedger struct {
-	pubKey crypto.PubKey
+	// 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
 }
 
 func NewPrivKeyLedger() (crypto.PrivKey, error) {
@@ -82,8 +90,8 @@ func (pk *PrivKeyLedger) Sign(msg []byte) crypto.Signature {
 	}
 
 	// if we have no pubkey yet, store it for future queries
-	if pk.pubKey.Empty() {
-		pk.pubKey = pub
+	if pk.CachedPubKey.Empty() {
+		pk.CachedPubKey = pub
 	}
 	return sig
 }
@@ -103,17 +111,17 @@ func (pk *PrivKeyLedger) PubKey() crypto.PubKey {
 // in the PubKey interface, so this function allows better error handling
 func (pk *PrivKeyLedger) getPubKey() (key crypto.PubKey, err error) {
 	// if we have no pubkey, set it
-	if pk.pubKey.Empty() {
+	if pk.CachedPubKey.Empty() {
 		dev, err := getLedger()
 		if err != nil {
 			return key, errors.WithMessage(err, "Can't connect to ledger")
 		}
-		pk.pubKey, _, err = signLedger(dev, []byte{0})
+		pk.CachedPubKey, _, err = signLedger(dev, []byte{0})
 		if err != nil {
 			return key, errors.WithMessage(err, "Can't sign with app")
 		}
 	}
-	return pk.pubKey, nil
+	return pk.CachedPubKey, nil
 }
 
 // Equals fulfils PrivKey Interface
@@ -219,11 +227,11 @@ func (pk PubKeyLedger) Equals(other crypto.PubKey) bool {
 
 func init() {
 	crypto.PrivKeyMapper.
-		RegisterImplementation(&PrivKeyLedger{}, "ledger", 0x10).
+		RegisterImplementation(&PrivKeyLedger{}, NameLedger, TypeLedger).
 		RegisterImplementation(MockPrivKeyLedger{}, "mock-ledger", 0x11)
 
 	crypto.PubKeyMapper.
-		RegisterImplementation(PubKeyLedger{}, "ledger", 0x10)
+		RegisterImplementation(PubKeyLedger{}, NameLedger, TypeLedger)
 }
 
 // Wrap fulfils interface for PrivKey struct