Feature: Add derive to SoftwareSigner

bitcoin_usb/seed_tools.py

@@ -1,5 +1,5 @@
 import logging
-from typing import Tuple
+from typing import Optional, Tuple
 
 import bdkpython as bdk
 from bitcointx import select_chain_params
@@ -11,17 +11,19 @@
 from .address_types import SimplePubKeyProvider
 
 
-def key_origin_fits_network(key_origin: str, network: bdk.Network):
-    network_str = key_origin.split("/")[2]
-    assert network_str.endswith("h")
-    network_index = int(network_str.replace("h", ""))
+def get_network_index(key_origin: str) -> Optional[int]:
+    splitted = key_origin.split("/")
+    if len(splitted) < 3:
+        logger.warning(f"{key_origin} has too few levels for a network_index")
+        return None
 
-    if network_index == 0:
-        return network == bdk.Network.BITCOIN
-    elif network_index == 1:
-        return network != bdk.Network.BITCOIN
-    else:
-        raise ValueError(f"Unknown network/coin type {network_str} in {key_origin}")
+    network_str = splitted[2]
+    if not network_str.endswith("h"):
+        logger.warning(f"The network index ({network_str}) must be hardened")
+        return None
+
+    network_index = int(network_str.replace("h", ""))
+    return network_index
 
 
 def get_mnemonic_seed(mnemonic: str):
@@ -47,8 +49,6 @@ def derive(mnemonic: str, key_origin: str, network: bdk.Network) -> Tuple[str, s
     Returns:
         Tuple[str, str]: xpub, fingerprint  (where fingerprint is the master fingerprint)
     """
-    if not key_origin_fits_network(key_origin, network):
-        raise ValueError(f"{key_origin} does not fit the selected network {network}")
 
     # Select network parameters
     network_params = {
@@ -64,11 +64,13 @@ def derive(mnemonic: str, key_origin: str, network: bdk.Network) -> Tuple[str, s
     # Create a master extended key from the seed
     master_key = CCoinExtKey.from_seed(seed_bytes)
 
-    # Derive the xpub at the specified origin
-    derived_key = master_key.derive_path(key_origin)
+    if key_origin == "m":
+        derived_key = master_key
+    else:
+        # Derive the xpub at the specified origin
+        derived_key = master_key.derive_path(key_origin)
 
     # Extract xpub
-
     xpub = str(derived_key.neuter())
 
     # Get the fingerprint

bitcoin_usb/software_signer.py

@@ -23,6 +23,10 @@ def __init__(self, mnemonic: str, network: bdk.Network) -> None:
         super().__init__(network=network)
         self.mnemonic = mnemonic
 
+    def derive(self, key_origin: str):
+        xpub, fingerprint = derive(self.mnemonic, key_origin, self.network)
+        return xpub
+
     def get_fingerprint(self) -> str:
         # it doesn't mattrer which AddressTypes i choose, because the fingerprint is identical for all
         address_type = AddressTypes.p2wsh

pyproject.toml

@@ -11,7 +11,7 @@ disable_error_code = "assignment"
 
 [tool.poetry]
 name = "bitcoin-usb"
-version = "0.2.1"
+version = "0.2.2"
 authors = ["andreasgriffin <[email protected]>"]
 license = "GPL-3.0"
 readme = "README.md"

tests/test_derivation.py

@@ -1,13 +1,11 @@
-import pytest
-
 from bitcoin_usb.address_types import (
     AddressTypes,
     DescriptorInfo,
     bdk,
     get_all_address_types,
     logging,
 )
-from bitcoin_usb.seed_tools import derive, derive_spk_provider
+from bitcoin_usb.seed_tools import derive_spk_provider, get_network_index
 
 # test seeds
 # seed1: spider manual inform reject arch raccoon betray moon document across main build
@@ -61,6 +59,56 @@ def test_correct_p2sh_p2wsh_derivation():
     assert spk_provider.fingerprint == "7c85f2b5".upper()
 
 
+def test_unusual_derivations():
+    #######
+    key_origin = "m"
+    spk_provider = derive_spk_provider(
+        "spider manual inform reject arch raccoon betray moon document across main build",
+        key_origin,
+        network,
+    )
+    print(spk_provider)
+    assert spk_provider.key_origin == key_origin
+    assert (
+        spk_provider.xpub
+        == "tpubD6NzVbkrYhZ4YjD4x8pv3PDE9bzSdF6FLsCroncohJbjpx4X9KykvHvZt2E2ybcrAuiNXWkVMt8TuJxYV7YMcgkfytvjMoCssXpL6pUp4Sc"
+    )
+    # compared with sparrow
+    assert spk_provider.fingerprint == "7c85f2b5".upper()
+
+    #######
+    key_origin = "m/1234567"
+    spk_provider = derive_spk_provider(
+        "spider manual inform reject arch raccoon betray moon document across main build",
+        key_origin,
+        network,
+    )
+    print(spk_provider)
+    assert spk_provider.key_origin == key_origin
+    assert (
+        spk_provider.xpub
+        == "tpubD9BDKDcxLHML2kmMeCuMF5QBETNQncf35TnwPvC5qhtLZupbxLEa4mhrpZZzfgmL8cxVTVUhgmUticQNWipZd19zatMmwg7LLgYjmFkqXpM"
+    )
+    # compared with sparrow
+    assert spk_provider.fingerprint == "7c85f2b5".upper()
+
+    #######
+    key_origin = "m/1234567/0h/1"
+    spk_provider = derive_spk_provider(
+        "spider manual inform reject arch raccoon betray moon document across main build",
+        key_origin,
+        network,
+    )
+    print(spk_provider)
+    assert spk_provider.key_origin == key_origin
+    assert (
+        spk_provider.xpub
+        == "tpubDDXENRdKZmizWdFbbgVf37n9zZ6yykSUdLYfhoPG2ubUgBVaUShGvdU17BPRwNNtLRrt8jVayR96JoW8yg9TdDo9tg7LeCWCqJ9V7NFnQqL"
+    )
+    # compared with sparrow
+    assert spk_provider.fingerprint == "7c85f2b5".upper()
+
+
 def test_correct_p2wsh_derivation():
     spk_provider = derive_spk_provider(
         "spider manual inform reject arch raccoon betray moon document across main build",
@@ -107,16 +155,6 @@ def test_correct_84derivation():
     assert spk_provider.fingerprint == "7c85f2b5".upper()
 
 
-def test_wrong_network():
-    with pytest.raises(ValueError) as exc_info:
-        xpub, fingerprint = derive(
-            "spider manual inform reject arch raccoon betray moon document across main build",
-            "m/48h/0h/0h/2h",
-            network,
-        )
-    assert str(exc_info.value) == "m/48h/0h/0h/2h does not fit the selected network Network.REGTEST"
-
-
 def test_multisig():
     spk_providers = [
         derive_spk_provider(
@@ -175,3 +213,12 @@ def test_multisig_unusual_key_origin(caplog):
         "m/44h/1h/0h does not match the default key origin m/48h/1h/0h/2h for this address type Multi Sig (SegWit/p2wsh)!"
         == caplog.records[-1].message
     )
+
+
+def test_get_network_index():
+    assert get_network_index("m/48h/0h/0h/2h") == 0
+    assert get_network_index("m/48h/1h/0h/2h") == 1
+
+    assert get_network_index("m/48h/1/0h/2h") == None
+
+    assert get_network_index("m/4") == None