Add support for creating wallet from private key (#24)

Author: Agusx1211

ethwallet/ethwallet.go

@@ -6,8 +6,8 @@ import (
 	"math/big"
 
 	"github.com/0xsequence/ethkit/ethrpc"
-	"github.com/0xsequence/ethkit/go-ethereum/accounts/abi/bind"
 	"github.com/0xsequence/ethkit/go-ethereum/accounts"
+	"github.com/0xsequence/ethkit/go-ethereum/accounts/abi/bind"
 	"github.com/0xsequence/ethkit/go-ethereum/common"
 	"github.com/0xsequence/ethkit/go-ethereum/common/hexutil"
 	"github.com/0xsequence/ethkit/go-ethereum/core/types"
@@ -30,6 +30,14 @@ type WalletOptions struct {
 	RandomWalletEntropyBitSize int
 }
 
+func NewWalletFromPrivateKey(key string) (*Wallet, error) {
+	hdnode, err := NewHDNodeFromPrivateKey(key)
+	if err != nil {
+		return nil, err
+	}
+	return &Wallet{hdnode: hdnode}, nil
+}
+
 func NewWalletFromHDNode(hdnode *HDNode, optPath ...accounts.DerivationPath) (*Wallet, error) {
 	var err error
 	derivationPath := DefaultBaseDerivationPath

ethwallet/ethwallet_test.go

@@ -34,3 +34,24 @@ func TestWalletSignMessage(t *testing.T) {
 	assert.NoError(t, err)
 	assert.True(t, valid)
 }
+
+func TestWalletSignMessageFromPrivateKey(t *testing.T) {
+	wallet, err := ethwallet.NewWalletFromPrivateKey("3c121e5b2c2b2426f386bfc0257820846d77610c20e0fd4144417fb8fd79bfb8")
+	assert.NoError(t, err)
+
+	address := wallet.Address()
+	assert.NoError(t, err)
+	assert.Equal(t, "0x95a7D93FEf729ed829C761FF0e035BB6Dd2c7052", address.String())
+
+	sig, err := wallet.SignMessage([]byte("hi"))
+	assert.NoError(t, err)
+
+	sigHash := hexutil.Encode(sig)
+	expected := "0x14c0b4cbb654b3da1140cdf5c000bfbf5db810f5a7fb339dd4514230d20e1bae4bf9ab78b6431b975260676a020cb4f7c164161776ee6fedbce39eb4103b257f1c"
+	assert.Equal(t, expected, sigHash)
+
+	// Lets validate the signature for good measure
+	valid, err := ethwallet.ValidateEthereumSignature(address.String(), []byte("hi"), sigHash)
+	assert.NoError(t, err)
+	assert.True(t, valid)
+}

ethwallet/hdnode.go

@@ -5,11 +5,11 @@ import (
 	"crypto/rand"
 	"fmt"
 
-	"github.com/btcsuite/btcd/chaincfg"
-	"github.com/btcsuite/btcutil/hdkeychain"
 	"github.com/0xsequence/ethkit/go-ethereum/accounts"
 	"github.com/0xsequence/ethkit/go-ethereum/common"
 	"github.com/0xsequence/ethkit/go-ethereum/crypto"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcutil/hdkeychain"
 	"github.com/tyler-smith/go-bip39"
 )
 
@@ -36,6 +36,19 @@ type HDNode struct {
 	address common.Address
 }
 
+func NewHDNodeFromPrivateKey(privateKey string) (*HDNode, error) {
+	key, err := crypto.HexToECDSA(privateKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return &HDNode{
+		privateKey: key,
+		publicKey:  &key.PublicKey,
+		address:    crypto.PubkeyToAddress(key.PublicKey),
+	}, nil
+}
+
 func NewHDNodeFromMnemonic(mnemonic string, path *accounts.DerivationPath) (*HDNode, error) {
 	entropy, err := MnemonicToEntropy(mnemonic)
 	if err != nil {