add: support derive extended master key from mnemonic.

Makefile

@@ -33,7 +33,7 @@ buildAllSDKIOS:
 
 # If you want to quickly verify some features of the gomobile, you can just package a little file test.
 buildIOSBase:
-	GOOS=ios gomobile bind -ldflags "-s -w" -v -target=ios/arm64  -o=${outdir}/${iosPackageName} ${pkgBase} ${pkgBtc}
+	GOOS=ios gomobile bind -ldflags "-s -w" -v -target=ios/arm64  -o=${outdir}/${iosPackageName} ${pkgBase} ${pkgBtc} ${pkgWallet}
 
 # 使用: make packageAll v=1.4
 # 结果: out 目录下将产生两个压缩包 wallet-SDK-ios.1.4.zip 和 wallet-SDK-android.1.4.zip 

core/wallet/mnemonic.go

@@ -1,6 +1,8 @@
 package wallet
 
 import (
+	"github.com/btcsuite/btcd/btcutil/hdkeychain"
+	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/tyler-smith/go-bip39"
 )
 
@@ -17,3 +19,15 @@ func IsValidMnemonic(mnemonic string) bool {
 	_, err := bip39.NewSeedWithErrorChecking(mnemonic, "")
 	return err == nil
 }
+
+func ExtendMasterKey(mnemonic string) (string, error) {
+	seed, err := bip39.NewSeedWithErrorChecking(mnemonic, "")
+	if err != nil {
+		return "", err
+	}
+	masterKey, err := hdkeychain.NewMaster(seed, &chaincfg.MainNetParams)
+	if err != nil {
+		return "", err
+	}
+	return masterKey.String(), nil
+}

core/wallet/mnemonic_test.go

@@ -1,9 +1,11 @@
 package wallet
 
 import (
+	"testing"
+
 	"github.com/ChainSafe/go-schnorrkel"
+	"github.com/stretchr/testify/require"
 	"github.com/tyler-smith/go-bip39"
-	"testing"
 )
 
 // const (
@@ -37,3 +39,11 @@ func TestSeed(t *testing.T) {
 	t.Log(seed)
 	t.Log(fromMnemonic)
 }
+
+func TestExtendMasterKey(t *testing.T) {
+	mn := "unaware oxygen allow method allow property predict various slice travel please priority"
+	extendedMasterKey, err := ExtendMasterKey(mn)
+	require.NoError(t, err)
+	want := "xprv9s21ZrQH143K2gM869SUAeSEGDM81UnyWG2tM7ZygYwN3PkveZmY799G6q7zkQYSQCMn7M7AMpP8Z6etKUoZo8x4hH1WVcKBCMZnVTNM8AD"
+	require.Equal(t, want, extendedMasterKey)
+}