Xor seedsave

shared/flow.py

@@ -13,7 +13,7 @@
 from users import make_users_menu
 from drv_entro import drv_entro_start
 from backups import clone_start, clone_write_data
-from xor_seed import xor_split_start, xor_restore_start
+from xor_seed import xor_save_start, xor_split_start, xor_restore_start
 from countdowns import countdown_pin_submenu, countdown_chooser
 
 # Optional feature: HSM
@@ -230,7 +230,8 @@ def vdisk_enabled():
 SeedXORMenu = [
     #         xxxxxxxxxxxxxxxx
     MenuItem("Split Existing", f=xor_split_start),
-    MenuItem("Restore Seed XOR", f=xor_restore_start),
+    MenuItem("Restore Seed XOR", menu=xor_restore_start),
+    MenuItem("Create XOR file", menu=xor_save_start)
 ]
 
 SeedFunctionsMenu = [

shared/manifest.py

@@ -53,6 +53,7 @@
 	'version.py',
 	'xor_seed.py',
 	'ftux.py',
+	'xor_seedsave.py',
 ], opt=0)
 
 # Optimize data-like files, since no need to debug them.

shared/pincodes.py

@@ -328,6 +328,9 @@ def has_duress_pin(self):
     def has_brickme_pin(self):
         return bool(self.state_flags & PA_HAS_BRICKME)
 
+    def has_tmp_seed(self):
+        return not self.tmp_value == False
+
     def reset(self):
         # start over, like when you commit a new seed
         return self.setup(self.pin, self.is_secondary)

shared/xor_seed.py

@@ -5,6 +5,8 @@
 # - for secret spliting on paper
 # - all combination of partial XOR seed phrases are working wallets
 #
+from menu import MenuItem, MenuSystem
+from xor_seedsave import XORSeedSaver
 import stash, ngu, chains, bip39, random
 from ux import ux_show_story, ux_enter_number, the_ux, ux_confirm, ux_dramatic_pause
 from seed import word_quiz, WordNestMenu, set_seed_value
@@ -107,8 +109,10 @@ async def xor_split_start(*a):
             continue
 
         for ws, part in enumerate(word_parts):
+            print('ws, part, %s, %s'%(ws, part))
             ch = await word_quiz(part, title='Word %s%%d is?' % chr(65+ws))
-            if ch == 'x': break
+            if ch == 'x': 
+                break
         else:
             break
 
@@ -152,8 +156,10 @@ async def all_done(new_words):
             import_xor_parts.clear()          # concern: we are contaminated w/ secrets
             return None
         elif ch == '1':
-            # do another list of words
-            nxt = XORWordNestMenu(num_words=24)
+            # do another list of words. 
+            # fast-track to manual entry if no secret set yet.
+            from pincodes import pa
+            nxt = XORWordNestMenu(num_words=24) if pa.is_secret_blank() else XORSourceMenu()
             the_ux.push(nxt)
         elif ch == '2':
             # done; import on temp basis, or be the main secret
@@ -169,6 +175,7 @@ async def all_done(new_words):
             else:
                 pa.tmp_secret(enc)
                 await ux_show_story("New master key in effect until next power down.")
+                goto_top_menu()
 
         return None
 
@@ -177,6 +184,32 @@ def tr_label(self):
         pn = len(import_xor_parts)
         return chr(65+pn) + ' Word' 
 
+
+
+
+class XORSourceMenu(MenuSystem):
+    def __init__(self):
+        items = [
+            MenuItem('Enter Manually', menu=self.manual_entry),
+            MenuItem('From SDCard', f=self.from_sdcard)
+        ]
+
+        super(XORSourceMenu, self).__init__(items)
+
+    async def manual_entry(*a):
+        return XORWordNestMenu(num_words=24)
+
+    async def from_sdcard(*a):
+        new_words = await XORSeedSaver().read_from_card()
+        if not new_words:
+            return None
+
+        return await XORWordNestMenu.all_done(new_words)
+
+
+
+
+
 async def show_n_parts(parts, chk_word):
     num_parts = len(parts)
     msg = 'Record these %d lists of 24-words each.\n\n' % num_parts
@@ -224,6 +257,34 @@ async def xor_restore_start(*a):
                     if len(words) == 24:
                         import_xor_parts.append(words)
 
-    return XORWordNestMenu(num_words=24)
+    # fast-track to manual entry if no secret set yet.
+    if pa.is_secret_blank():
+        return XORWordNestMenu(num_words=24)
+
+    return XORSourceMenu()
+
+async def xor_save_start(*a):
+    from pincodes import pa 
+    if pa.has_tmp_seed():
+        ch = await ux_show_story('''\
+The current master key is a temporary one; the file will be encrypted with this key.
+
+Press OK to continue. X to cancel.
+''')
+        if ch == 'x': return
+
+    ch = await ux_show_story('''\
+Have your 24-word phrase ready. You will enter the 24 words which will then be encrypted using the master key and stored on your SDCard.
+
+Press OK to continue. X to cancel.
+''')
+    if ch == 'x': return
+
+
+    async def callback(new_words):
+        WordNestMenu.pop_all()
+        return await XORSeedSaver().save_to_card(new_words)
+
+    return WordNestMenu(num_words=24, done_cb=callback)
 
 # EOF

shared/xor_seedsave.py

@@ -0,0 +1,113 @@
+# (c) Copyright 2020 by Coinkite Inc. This file is covered by license found in COPYING-CC.
+#
+# xor_seedsave.py - Save xor seedwords into encrypted file on MicroSD (if desired)
+#
+import sys, stash, ujson, os, ngu
+from actions import file_picker
+from files import CardSlot, CardMissingError
+from ux import ux_show_story
+
+class XORSeedSaver:
+    # Encrypts a 12-word seed very carefully, and appends
+    # to a file on MicroSD card.
+    # AES-256 CTR with key=SHA256(SHA256(salt + derived key off master + salt))
+    # where: salt=sha256(microSD serial # details)
+
+    def _calc_key(self, card):
+        # calculate the key to be used.
+        if getattr(self, 'key', None): return
+
+        try:
+            salt = card.get_id_hash()
+
+            with stash.SensitiveValues(bypass_pw=True) as sv:
+                self.key = bytearray(sv.encryption_key(salt))
+
+        except:
+            self.key = None
+
+    def _read(self, filename):
+        # Return 24 words from encrypted file, or empty list if fail.
+        # Fail silently in all cases.
+        decrypt = ngu.aes.CTR(self.key)
+
+        try:
+            msg = open(filename, 'rb').read()
+            txt = decrypt.cipher(msg)
+            val = ujson.loads(txt)
+
+            # If contents are not what we expect, return nothing
+            if not type(val) is list:
+                return []
+            if not len(val) == 24:
+                return []
+
+            return val
+        except:
+            return []
+
+    def _write(self, filename, words):
+        # Encrypt and save words to file.
+        # Allow exceptions to throw as validation should 
+        # have been performed before calling.
+        encrypt = ngu.aes.CTR(self.key)
+        json = ujson.dumps(words)
+        contents = encrypt.cipher(json)
+        open(filename, 'wb').write(contents)
+
+    async def read_from_card(self): 
+        import pyb
+        if not pyb.SDCard().present():
+            await ux_show_story("Insert an SDCard and try again.")
+            return None
+
+        choices = await file_picker(None, suffix='xor')
+        filename = await file_picker('Choose your XOR file.', choices=choices)
+
+        if not filename:
+            return None
+
+        # Read file, decrypt and make a menu to show; OR return None
+        # if any error hit.
+        try:
+            with CardSlot() as card:
+                self._calc_key(card)
+                if not self.key:
+                    await ux_show_story("Failed to read file!\n\nNo action has been taken.")
+                    return None
+
+                data = self._read(filename)
+                if not data:
+                    await ux_show_story("Failed to read file!\n\nNo action has been taken.")
+                    return None
+
+                return data
+        except CardMissingError:
+            # not an error: they just aren't using feature
+            await ux_show_story("Failed to read file!\n\nNo action has been taken.")
+            return None
+
+    async def save_to_card(self, words):
+        msg = ('Confirm these %d secret words:\n') % len(words)
+        msg += '\n'.join('%2d: %s' % (i+1, w) for i,w in enumerate(words))
+        ch = await ux_show_story(msg, sensitive=True)
+        if ch == 'x': return
+
+        import pyb
+        while not pyb.SDCard().present():
+            ch = await ux_show_story('Please insert an SDCard!\n\nPress OK to continue, X to cancel')
+            if ch == 'x': return
+
+        from glob import dis
+        # Show progress:
+        dis.fullscreen('Encrypting...')
+
+        with CardSlot() as card:
+            filename, nice = card.pick_filename('seedwords.xor')
+            self._calc_key(card)
+            self._write(filename, words)
+            await ux_show_story('XOR file written:\n\n%s' % nice)
+
+        return None
+
+# EOF

testing/test_seed_xor.py

@@ -22,7 +22,7 @@
     ( [ones32]*7, ones32),
     ( [ones32]*4, zero32),
 ])
-def test_import_xor(incl_self, parts, expect, goto_home, pick_menu_item, cap_story, need_keypress, cap_menu, word_menu_entry, get_secrets, reset_seed_words, set_seed_words):
+def test_import_xor_manual(incl_self, parts, expect, goto_home, pick_menu_item, cap_story, need_keypress, cap_menu, word_menu_entry, get_secrets, reset_seed_words, set_seed_words):
 
     # values from docs/seed-xor.md, and some easy cases
 
@@ -50,6 +50,8 @@ def test_import_xor(incl_self, parts, expect, goto_home, pick_menu_item, cap_sto
     else:
         need_keypress('y')
 
+    pick_menu_item('Enter Manually')
+
     #time.sleep(0.01)
 
     for n, part in enumerate(parts):
@@ -65,6 +67,7 @@ def test_import_xor(incl_self, parts, expect, goto_home, pick_menu_item, cap_sto
 
         if n != len(parts)-1:
             need_keypress('1')
+            pick_menu_item('Enter Manually')
         else:
             # correct anticipated checksum word
             chk_word = expect.split()[-1]
@@ -165,6 +168,7 @@ def test_import_zero_set(goto_home, pick_menu_item, cap_story, need_keypress, ca
     assert 'you have a seed already' in body
     assert '(1) to include this Coldcard' in body
     need_keypress('y')
+    pick_menu_item('Enter Manually')
 
     #time.sleep(0.01)
 
@@ -181,6 +185,8 @@ def test_import_zero_set(goto_home, pick_menu_item, cap_story, need_keypress, ca
             return
 
         need_keypress('1')
+        pick_menu_item('Enter Manually')
+
 
     raise pytest.fail("reached")
 

unix/work/MicroSD/.gitignore

@@ -6,4 +6,5 @@
 *.pdf
 *.dfu
 *.txn
+*.xor
 .tmp.tmp