[crypto] Refactor crypto to be generic / pull ed25519 out of transact…

…ion logic (#9)

* [crypto] Refactor crypto to be generic / pull ed25519 out of transaction logic

* [crypto] Fix go client with bytes function

account.go

@@ -1,8 +1,6 @@
 package aptos
 
 import (
-	"crypto"
-	"crypto/ed25519"
 	"crypto/rand"
 	"encoding/hex"
 	"errors"
@@ -12,6 +10,17 @@ import (
 	"golang.org/x/crypto/sha3"
 )
 
+// Seeds for deriving addresses from addresses
+const (
+	Ed25519Scheme         = uint8(0)
+	MultiEd25519Scheme    = uint8(1)
+	SingleKeyScheme       = uint8(2)
+	MultiKeyScheme        = uint8(3)
+	deriveObjectScheme    = uint8(252)
+	namedObjectScheme     = uint8(254)
+	resourceAccountScheme = uint8(255)
+)
+
 type AccountAddress [32]byte
 
 // TODO: find nicer naming for this? Move account to a package so this can be account.ONE ? Wrap in a singleton struct for Account.One ?
@@ -46,33 +55,58 @@ func (aa AccountAddress) String() string {
 func (aa AccountAddress) MarshalBCS(bcs *Serializer) {
 	bcs.FixedBytes(aa[:])
 }
+
 func (aa *AccountAddress) UnmarshalBCS(bcs *Deserializer) {
 	bcs.ReadFixedBytesInto((*aa)[:])
 }
+
 func (aa *AccountAddress) Random() {
 	rand.Read((*aa)[:])
 }
-func (aa *AccountAddress) FromEd25519PubKey(pubkey ed25519.PublicKey) {
-	// TODO: Other SDK implementations have an internal AuthenticationKey type to wrap this. Maybe follow that pattern later?
+
+func (aa *AccountAddress) FromPublicKey(pubkey PublicKey) {
 	hasher := sha3.New256()
-	hasher.Write(pubkey[:])
-	hasher.Write([]byte{0})
+	hasher.Write(pubkey.Bytes())
+	hasher.Write([]byte{pubkey.Scheme()})
 	hasher.Sum((*aa)[:0])
 }
 
+func (aa *AccountAddress) NamedObjectAddress(seed []byte) (accountAddress AccountAddress) {
+	return aa.DerivedAddress(seed, namedObjectScheme)
+}
+
+func (aa *AccountAddress) ObjectAddressFromObject(objectAddress *AccountAddress) (accountAddress AccountAddress) {
+	return aa.DerivedAddress(objectAddress[:], deriveObjectScheme)
+}
+
+func (aa *AccountAddress) ResourceAccount(seed []byte) (accountAddress AccountAddress) {
+	return aa.DerivedAddress(seed, resourceAccountScheme)
+}
+
+// DerivedAddress addresses are derived by the address, the seed, then the type byte
+func (aa *AccountAddress) DerivedAddress(seed []byte, type_byte uint8) (accountAddress AccountAddress) {
+	accountAddress = AccountAddress{}
+	hasher := sha3.New256()
+	hasher.Write(aa[:])
+	hasher.Write(seed[:])
+	hasher.Write([]byte{type_byte})
+	hasher.Sum(accountAddress[:])
+	return
+}
+
 type Account struct {
 	Address    AccountAddress
-	PrivateKey crypto.PrivateKey
+	PrivateKey PrivateKey
 }
 
 func NewAccount() (*Account, error) {
-	pubkey, privkey, err := ed25519.GenerateKey(nil)
+	privkey, pubkey, err := GenerateEd5519Keys()
 	if err != nil {
 		return nil, err
 	}
 	out := &Account{}
-	out.Address.FromEd25519PubKey(pubkey)
-	out.PrivateKey = privkey
+	out.Address.FromPublicKey(pubkey)
+	out.PrivateKey = &privkey
 	return out, nil
 }
 

cmd/goclient/goclient.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"crypto/ed25519"
 	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
@@ -213,14 +212,14 @@ func main() {
 			amount := uint64(200_000_000)
 			err = client.Fund(alice.Address, amount)
 			maybefail(err, "faucet err: %s", err)
-			fmt.Fprintf(os.Stdout, "new account %s funded for %d, privkey = %s\n", alice.Address.String(), amount, hex.EncodeToString(alice.PrivateKey.(ed25519.PrivateKey)[:]))
+			fmt.Fprintf(os.Stdout, "new account %s funded for %d, privkey = %s\n", alice.Address.String(), amount, hex.EncodeToString(alice.PrivateKey.Bytes()))
 
 			bob, err := aptos.NewAccount()
 			maybefail(err, "new account: %s", err)
 			//amount = uint64(10_000_000)
 			err = client.Fund(bob.Address, amount)
 			maybefail(err, "faucet err: %s", err)
-			fmt.Fprintf(os.Stdout, "new account %s funded for %d, privkey = %s\n", bob.Address.String(), amount, hex.EncodeToString(bob.PrivateKey.(ed25519.PrivateKey)[:]))
+			fmt.Fprintf(os.Stdout, "new account %s funded for %d, privkey = %s\n", bob.Address.String(), amount, hex.EncodeToString(bob.PrivateKey.Bytes()))
 
 			time.Sleep(2 * time.Second)
 			stxn, err := aptos.APTTransferTransaction(client, alice, bob.Address, 42)

crypto.go

@@ -0,0 +1,29 @@
+package aptos
+
+// Signer a generic interface for any kind of signing
+type Signer interface {
+	Sign(msg []byte) (authenticator Authenticator, err error)
+}
+
+// PrivateKey a generic interface for a signing private key
+type PrivateKey interface {
+	Signer
+
+	/// PubKey Retrieve the public key for signature verification
+	PubKey() PublicKey
+
+	Bytes() []byte
+}
+
+// PublicKey a generic interface for a public key associated with the private key
+type PublicKey interface {
+	// BCSStruct The public key must be serializable or it will not be used in transactions
+	BCSStruct
+
+	// Bytes the raw bytes for an authenticator
+	Bytes() []byte
+	// Scheme The scheme used for address derivation
+	Scheme() uint8
+
+	// TODO: add verify
+}

ed25519.go

@@ -0,0 +1,68 @@
+package aptos
+
+import (
+	"crypto/ed25519"
+)
+
+type Ed25519PrivateKey struct {
+	inner ed25519.PrivateKey
+}
+
+func GenerateEd5519Keys() (privkey Ed25519PrivateKey, pubkey Ed25519PublicKey, err error) {
+	pub, priv, err := ed25519.GenerateKey(nil)
+	if err != nil {
+		return
+	}
+	privkey = Ed25519PrivateKey{priv}
+	pubkey = Ed25519PublicKey{pub}
+	return
+}
+
+func (key *Ed25519PrivateKey) PubKey() PublicKey {
+	pubkey := key.inner.Public()
+	return Ed25519PublicKey{
+		pubkey.(ed25519.PublicKey),
+	}
+}
+
+func (key *Ed25519PrivateKey) Bytes() []byte {
+	return key.inner[:]
+}
+
+func (key *Ed25519PrivateKey) Sign(msg []byte) (authenticator Authenticator, err error) {
+	publicKeyBytes := key.PubKey().Bytes()
+	signature := ed25519.Sign(key.inner, msg)
+
+	auth := &Ed25519Authenticator{}
+	copy(auth.PublicKey[:], publicKeyBytes[:])
+	copy(auth.Signature[:], signature[:]) // TODO: Signature type?
+	authenticator = Authenticator{
+		AuthenticatorEd25519,
+		auth,
+	}
+	return
+}
+
+type Ed25519PublicKey struct {
+	inner ed25519.PublicKey
+}
+
+func (key Ed25519PublicKey) Bytes() []byte {
+	return key.inner[:]
+}
+func (key Ed25519PublicKey) Scheme() uint8 {
+	return Ed25519Scheme
+}
+
+func (key Ed25519PublicKey) MarshalBCS(bcs *Serializer) {
+	bcs.FixedBytes(key.inner[:])
+}
+
+func (key Ed25519PublicKey) UnmarshalBCS(bcs *Deserializer) {
+	key = Ed25519PublicKey{}
+	bytes := bcs.ReadFixedBytes(32)
+	if bcs.Error() != nil {
+		return
+	}
+	copy(key.inner[:], bytes)
+}

transactions.go

@@ -1,7 +1,6 @@
 package aptos
 
 import (
-	"crypto/ed25519"
 	"errors"
 	"fmt"
 	"math/big"
@@ -31,6 +30,7 @@ func (txn *RawTransaction) MarshalBCS(bcs *Serializer) {
 	bcs.U64(txn.ExpirationTimetampSeconds)
 	bcs.U8(txn.ChainId)
 }
+
 func (txn *RawTransaction) UnmarshalBCS(bcs *Deserializer) {
 	txn.Sender.UnmarshalBCS(bcs)
 	txn.SequenceNumber = bcs.U64()
@@ -40,6 +40,7 @@ func (txn *RawTransaction) UnmarshalBCS(bcs *Deserializer) {
 	txn.ExpirationTimetampSeconds = bcs.U64()
 	txn.ChainId = bcs.U8()
 }
+
 func (txn *RawTransaction) SignableBytes() (signableBytes []byte, err error) {
 	ser := Serializer{}
 	txn.MarshalBCS(&ser)
@@ -54,27 +55,20 @@ func (txn *RawTransaction) SignableBytes() (signableBytes []byte, err error) {
 	copy(signableBytes[len(prehash):], txnbytes)
 	return signableBytes, nil
 }
-func (txn *RawTransaction) SignEd25519(privateKey ed25519.PrivateKey) (stxn *SignedTransaction, err error) {
+
+func (txn *RawTransaction) Sign(privateKey PrivateKey) (stxn *SignedTransaction, err error) {
 	signableBytes, err := txn.SignableBytes()
 	if err != nil {
 		return
 	}
-	signature := ed25519.Sign(privateKey, signableBytes)
-	eauth := &Ed25519Authenticator{}
-	pubkey := privateKey.Public()
-	if pkb, ok := pubkey.(ed25519.PublicKey); ok {
-		copy(eauth.PublicKey[:], pkb[:])
-	} else {
-		panic(fmt.Sprintf("could not get bytes from pubkey: %T %#v", pubkey, pubkey))
-	}
-	copy(eauth.Signature[:], signature)
-	aa := Authenticator{
-		Kind: AuthenticatorEd25519,
-		Auth: eauth,
+	authenticator, err := privateKey.Sign(signableBytes)
+	if err != nil {
+		return
 	}
+
 	stxn = &SignedTransaction{
 		Transaction:   *txn,
-		Authenticator: aa,
+		Authenticator: authenticator,
 	}
 	return
 }

transactions_test.go

@@ -1,7 +1,6 @@
 package aptos
 
 import (
-	"crypto/ed25519"
 	"encoding/binary"
 	"testing"
 
@@ -40,7 +39,7 @@ func TestRawTransactionSign(t *testing.T) {
 		ChainId:                   4,
 	}
 
-	stxn, err := txn.SignEd25519(sender.PrivateKey.(ed25519.PrivateKey))
+	stxn, err := txn.Sign(sender.PrivateKey)
 	assert.NoError(t, err)
 
 	_, ok := stxn.Authenticator.Auth.(*Ed25519Authenticator)

util.go

@@ -1,7 +1,6 @@
 package aptos
 
 import (
-	"crypto/ed25519"
 	"encoding/binary"
 	"time"
 )
@@ -51,6 +50,6 @@ func APTTransferTransaction(client *Client, sender *Account, dest AccountAddress
 		ChainId:                   chainId,
 	}
 
-	stxn, err = txn.SignEd25519(sender.PrivateKey.(ed25519.PrivateKey))
+	stxn, err = txn.Sign(sender.PrivateKey)
 	return stxn, err
 }