Support slip39 extendable backups

Author: onvej-sl

slip39/api.py

@@ -983,6 +983,7 @@ def create(
     iteration_exponent: int	= 1,
     cryptopaths: Optional[Sequence[Union[str,Tuple[str,str],Tuple[str,str,str]]]] = None,  # default: ETH, BTC at default path, format
     strength: Optional[int]	= None,		# Default: 128
+    extendable: bool = True,
 ) -> Tuple[str,int,Dict[str,Tuple[int,List[str]]], Sequence[Sequence[Account]], bool]:
     """Creates a SLIP-39 encoding for supplied master_secret Entropy, and 1 or more Cryptocurrency
     accounts.  Returns the Details, in a form directly compatible with the layout.produce_pdf API.
@@ -1084,7 +1085,8 @@ def create(
         groups		= g_dims,
         master_secret	= master_secret,
         passphrase	= passphrase,
-        iteration_exponent= iteration_exponent
+        iteration_exponent= iteration_exponent,
+        extendable	= extendable
     )
 
     groups			= {
@@ -1112,6 +1114,7 @@ def mnemonics(
     passphrase: Optional[Union[bytes,str]] = None,
     iteration_exponent: int	= 1,
     strength: int		= BITS_DEFAULT,
+    extendable: bool = True,
 ) -> List[List[str]]:
     """Generate SLIP39 mnemonics for the supplied group_threshold of the given groups.  Will generate a
      random master_secret, if necessary.
@@ -1143,6 +1146,7 @@ def mnemonics(
         passphrase	= passphrase or b"",  # python-shamir-mnemonic requires bytes
         extendable	= False,
         iteration_exponent = iteration_exponent,
+        extendable = extendable,
     )
 
 

slip39/api_test.py

@@ -229,6 +229,30 @@ def test_account_format():
     assert acct.address == 'bc1qcr8te4kr609gcawutmrza0j4xv80jy8z306fyu'
 
 
+def test_slip39_non_extendable_compatibility():
+    """Test that SLIP-39 non-extendable backup of a wallet generated by Trezor can be recevered"""
+    # The 4th vector from https://github.com/trezor/python-shamir-mnemonic/blob/master/vectors.json
+    mnemonics = [
+      "shadow pistol academic always adequate wildlife fancy gross oasis cylinder mustang wrist rescue view short owner flip making coding armed",
+      "shadow pistol academic acid actress prayer class unknown daughter sweater depict flip twice unkind craft early superior advocate guest smoking"
+    ]
+    account = Account( crypto="Bitcoin", format="legacy" )
+    account.from_mnemonic( "\n".join(mnemonics), passphrase = 'TREZOR', path="m/" )
+    assert account.xprvkey == "xprv9s21ZrQH143K2nNuAbfWPHBtfiSCS14XQgb3otW4pX655q58EEZeC8zmjEUwucBu9dPnxdpbZLCn57yx45RBkwJHnwHFjZK4XPJ8SyeYjYg"
+
+
+def test_slip39_extendable_trezor_compatibility():
+    """Test that SLIP-39 extendable backup of a wallet generated by Trezor can be recevered"""
+    # The 43th vector from https://github.com/trezor/python-shamir-mnemonic/blob/master/vectors.json
+    mnemonics = [
+      "enemy favorite academic acid cowboy phrase havoc level response walnut budget painting inside trash adjust froth kitchen learn tidy punish",
+      "enemy favorite academic always academic sniff script carpet romp kind promise scatter center unfair training emphasis evening belong fake enforce"
+    ]
+    account = Account( crypto="Bitcoin", format="legacy" )
+    account.from_mnemonic( "\n".join(mnemonics), passphrase = 'TREZOR', path="m/" )
+    assert account.xprvkey == "xprv9s21ZrQH143K4FS1qQdXYAFVAHiSAnjj21YAKGh2CqUPJ2yQhMmYGT4e5a2tyGLiVsRgTEvajXkxhg92zJ8zmWZas9LguQWz7WZShfJg6RS"
+
+
 def test_account_from_mnemonic():
     """Test all the ways the entropy 0xffff...ffff can be encoded and HD Wallets derived."""
     # Raw 0xffff...ffff entropy as Seed.  Not BIP-39 decoded (hashed) via mnemonic to produce Seed.
@@ -397,11 +421,11 @@ def test_create():
 
     assert details_xmas.groups == {
         "fren": ( 3, [
-            "academic acid academic acne academic academic academic academic academic academic academic academic academic academic academic academic academic carpet making building",
-            "academic acid academic agree depart dance galaxy acrobat mayor disaster quick justice ordinary agency plunge should pupal emphasis security obtain",
-            "academic acid academic amazing crush royal faint spit briefing craft floral negative work depend prune adapt merit romp home elevator",
-            "academic acid academic arcade cargo unfold aunt spider muscle bedroom triumph theory gather dilemma building similar chemical object cinema salon",
-            "academic acid academic axle crush swing purple violence teacher curly total equation clock mailman display husband tendency smug laundry disaster"
+            "academic agency academic acne academic academic academic academic academic academic academic academic academic academic academic academic academic arena diet involve",
+            "academic agency academic agree closet maximum rumor beyond organize taught game helpful fishing brother bumpy nervous presence document buyer reject",
+            "academic agency academic amazing arena meaning advocate hearing hunting pecan lilac device oasis teacher traffic retailer criminal scene flip true",
+            "academic agency academic arcade cover acne safari item vanish else superior focus skin webcam venture clay loan various impact client",
+            "academic agency academic axle carpet blimp stilt intend august racism webcam replace gather rich sweater mandate maximum rumor drink scene"
         ] ),
     }