Support importing BIP32 xpub/xpriv

README.md

@@ -23,7 +23,9 @@ Constructors:
 
 * `generate([icap])` - create an instance based on a new random key (setting `icap` to true will generate an address suitable for the `ICAP Direct mode`)
 * `fromPrivateKey(input)` - create an instance based on a raw private key
+* `fromExtendedPrivateKey(input)` - create an instance based on a BIP32 xprv
 * `fromPublicKey(input)` - create an instance based on a public key (certain methods will not be available)
+* `fromExtendedPublicKey(input)` - create an instance based on a BIP32 xpub
 * `fromV1(input, password)` - import a wallet (Version 1 of the Ethereum wallet format)
 * `fromV3(input, password, [nonStrict])` - import a wallet (Version 3 of the Ethereum wallet format). Set `nonStrict` true to accept files with mixed-caps.
 * `fromEthSale(input, password)` - import an Ethereum Pre Sale wallet

index.js

@@ -2,6 +2,8 @@ var ethUtil = require('ethereumjs-util')
 var crypto = require('crypto')
 var scryptsy = require('scrypt.js')
 var uuid = require('uuid')
+var secp256k1 = require('secp256k1')
+var bs58check = require('bs58check')
 
 function assert (val, msg) {
   if (!val) {
@@ -163,10 +165,25 @@ Wallet.fromPublicKey = function (pub) {
   return new Wallet(null, pub)
 }
 
+Wallet.fromExtendedPublicKey = function (pub) {
+  assert(pub.slice(0, 4) === 'xpub', 'Not an extended public key')
+  pub = bs58check.decode(pub).slice(45)
+  // Convert to an Ethereum public key
+  pub = secp256k1.publicKeyConvert(pub, false).slice(1)
+  return Wallet.fromPublicKey(pub)
+}
+
 Wallet.fromPrivateKey = function (priv) {
   return new Wallet(priv)
 }
 
+Wallet.fromExtendedPrivateKey = function (priv) {
+  assert(priv.slice(0, 4) === 'xprv', 'Not an extended private key')
+  var tmp = bs58check.decode(priv)
+  assert(tmp[45] === 0, 'Invalid extended private key')
+  return Wallet.fromPrivateKey(tmp.slice(46))
+}
+
 // https://github.com/ethereum/go-ethereum/wiki/Passphrase-protected-key-store-spec
 Wallet.fromV1 = function (input, password) {
   assert(typeof password === 'string')

package.json

@@ -25,8 +25,10 @@
   "homepage": "https://github.com/axic/ethereumjs-wallet",
   "dependencies": {
     "aes-js": "^0.2.3",
+    "bs58check": "^1.0.8",
     "ethereumjs-util": "^4.3.0",
     "scrypt.js": "^0.1.0",
+    "secp256k1": "^3.0.1",
     "uuid": "^2.0.1",
     "utf8": "^2.1.1"
   },

test/index.js

@@ -73,6 +73,21 @@ describe('public key only wallet', function () {
   })
 })
 
+describe('.fromExtendedPrivateKey()', function () {
+  it('should work', function () {
+    var xprv = 'xprv9s21ZrQH143K4KqQx9Zrf1eN8EaPQVFxM2Ast8mdHn7GKiDWzNEyNdduJhWXToy8MpkGcKjxeFWd8oBSvsz4PCYamxR7TX49pSpp3bmHVAY'
+    assert.equal(Wallet.fromExtendedPrivateKey(xprv).getAddressString(), '0xb800bf5435f67c7ee7d83c3a863269969a57c57c')
+  })
+})
+
+describe('.fromExtendedPublicKey()', function () {
+  it('should work', function () {
+    var xpub = 'xpub661MyMwAqRbcGout4B6s29b6gGQsowyoiF6UgXBEr7eFCWYfXuZDvRxP9zEh1Kwq3TLqDQMbkbaRpSnoC28oWvjLeshoQz1StZ9YHM1EpcJ'
+    assert.equal(Wallet.fromExtendedPublicKey(xpub).getAddressString(), '0xb800bf5435f67c7ee7d83c3a863269969a57c57c')
+  })
+})
+
+
 describe('.generate()', function () {
   it('should generate an account', function () {
     assert.equal(Wallet.generate().getPrivateKey().length, 32)