core: support load device with SLIP-39

updates #356

core/src/apps/management/load_device.py

@@ -1,5 +1,5 @@
 from trezor import config, wire
-from trezor.crypto import bip39
+from trezor.crypto import bip39, slip39
 from trezor.messages.Success import Success
 from trezor.pin import pin_to_int
 from trezor.ui.text import Text
@@ -9,14 +9,29 @@ from apps.common.confirm import require_confirm
 
 
 async def load_device(ctx, msg):
-    # TODO implement SLIP-39
     if storage.is_initialized():
         raise wire.UnexpectedMessage("Already initialized")
 
     if msg.node is not None:
         raise wire.ProcessError("LoadDevice.node is not supported")
 
-    if not msg.skip_checksum and not bip39.check(msg.mnemonic):
+    if not msg.mnemonics:
+        raise wire.ProcessError("No mnemonic provided")
+
+    word_count = len(msg.mnemonics[0].split(" "))
+    for m in msg.mnemonics[1:]:
+        if word_count != len(m.split(" ")):
+            raise wire.ProcessError(
+                "All shares are required to have the same number of words"
+            )
+
+    mnemonic_type = mnemonic.type_from_word_count(word_count)
+
+    if (
+        mnemonic_type == mnemonic.TYPE_BIP39
+        and not msg.skip_checksum
+        and not bip39.check(msg.mnemonics[0])
+    ):
         raise wire.ProcessError("Mnemonic is not valid")
 
     text = Text("Loading seed")
@@ -24,11 +39,17 @@ async def load_device(ctx, msg):
     text.normal("Continue only if you", "know what you are doing!")
     await require_confirm(ctx, text)
 
+    if mnemonic_type == mnemonic.TYPE_BIP39:
+        secret = msg.mnemonics[0].encode()
+    elif mnemonic_type == mnemonic.TYPE_SLIP39:
+        identifier, iteration_exponent, secret = slip39.combine_mnemonics(msg.mnemonics)
+        storage.device.set_slip39_identifier(identifier)
+        storage.device.set_slip39_iteration_exponent(iteration_exponent)
+    else:
+        raise RuntimeError("Unknown mnemonic type")
+
     storage.device.store_mnemonic_secret(
-        secret=msg.mnemonic.encode(),
-        mnemonic_type=mnemonic.TYPE_BIP39,
-        needs_backup=True,
-        no_backup=False,
+        secret, mnemonic_type, needs_backup=True, no_backup=False
     )
     storage.device.load_settings(
         use_passphrase=msg.passphrase_protection, label=msg.label