From 6b45070b2f7c899dd9bdd1a7bf423ad23a014374 Mon Sep 17 00:00:00 2001
From: ThomasV <thomasv@electrum.org>
Date: Tue, 20 Jun 2017 10:47:02 +0200
Subject: [PATCH] allow arbitrary derivations with bip39 seeds, to let multibit
 users recover funds

---
 gui/qt/installwizard.py |  2 +-
 lib/base_wizard.py      | 26 ++++++++++----------------
 lib/bitcoin.py          | 15 +++++++++++++++
 3 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/gui/qt/installwizard.py b/gui/qt/installwizard.py
index 6288163f..7d1d6c68 100644
--- a/gui/qt/installwizard.py
+++ b/gui/qt/installwizard.py
@@ -453,7 +453,7 @@ class InstallWizard(QDialog, MessageBoxMixin, BaseWizard):
         line = QLineEdit()
         line.setText(default)
         def f(text):
-            self.next_button.setEnabled(test(text))
+            self.next_button.setEnabled(test(unicode(text)))
         line.textEdited.connect(f)
         vbox.addWidget(line)
         vbox.addWidget(WWLabel(warning))
diff --git a/lib/base_wizard.py b/lib/base_wizard.py
index c86c56e8..31cb426f 100644
--- a/lib/base_wizard.py
+++ b/lib/base_wizard.py
@@ -222,21 +222,16 @@ class BaseWizard(object):
             # This is partially compatible with BIP45; assumes index=0
             self.on_hw_derivation(name, device_info, "m/45'/0")
         else:
-            f = lambda x: self.run('on_hw_derivation', name, device_info, bip44_derivation(int(x)))
-            self.account_id_dialog(f)
+            f = lambda x: self.run('on_hw_derivation', name, device_info, str(x))
+            self.derivation_dialog(f)
 
-    def account_id_dialog(self, f):
+    def derivation_dialog(self, f):
+        default = bip44_derivation(0)
         message = '\n'.join([
-            _('Enter your BIP44 account number here.'),
-            _('If you are not sure what this is, leave this field to zero.')
+            _('Enter your wallet derivation here.'),
+            _('If you are not sure what this is, leave this field unchanged.')
         ])
-        def is_int(x):
-            try:
-                int(x)
-                return True
-            except:
-                return False
-        self.line_dialog(run_next=f, title=_('Account Number'), message=message, default='0', test=is_int)
+        self.line_dialog(run_next=f, title=_('Derivation'), message=message, default=default, test=bitcoin.is_bip32_derivation)
 
     def on_hw_derivation(self, name, device_info, derivation):
         from keystore import hardware_keystore
@@ -293,17 +288,16 @@ class BaseWizard(object):
             raise BaseException('Unknown seed type', seed_type)
 
     def on_restore_bip39(self, seed, passphrase):
-        f = lambda x: self.run('on_bip44', seed, passphrase, int(x))
-        self.account_id_dialog(f)
+        f = lambda x: self.run('on_bip44', seed, passphrase, str(x))
+        self.derivation_dialog(f)
 
     def create_keystore(self, seed, passphrase):
         k = keystore.from_seed(seed, passphrase)
         self.on_keystore(k)
 
-    def on_bip44(self, seed, passphrase, account_id):
+    def on_bip44(self, seed, passphrase, derivation):
         k = keystore.BIP32_KeyStore({})
         bip32_seed = keystore.bip39_to_seed(seed, passphrase)
-        derivation = bip44_derivation(account_id)
         k.add_xprv_from_seed(bip32_seed, 0, derivation)
         self.on_keystore(k)
 
diff --git a/lib/bitcoin.py b/lib/bitcoin.py
index 770d3574..bcc289b2 100644
--- a/lib/bitcoin.py
+++ b/lib/bitcoin.py
@@ -820,6 +820,21 @@ def xpub_from_pubkey(xtype, cK):
     return serialize_xpub(xtype, chr(0)*32, cK)
 
 
+def bip32_derivation(s):
+    assert s.startswith('m/')
+    s = s[2:]
+    for n in s.split('/'):
+        if n == '': continue
+        i = int(n[:-1]) + BIP32_PRIME if n[-1] == "'" else int(n)
+        yield i
+
+def is_bip32_derivation(x):
+    try:
+        [ i for i in bip32_derivation(x)]
+        return True
+    except :
+        return False
+
 def bip32_private_derivation(xprv, branch, sequence):
     assert sequence.startswith(branch)
     if branch == sequence: