Save channel seed in localconfig

electrum/lnpeer.py

@@ -20,7 +20,6 @@ import aiorpcx
 
 from .crypto import sha256, sha256d
 from . import bitcoin
-from .bip32 import BIP32Node
 from . import ecc
 from .ecc import sig_string_from_r_and_s, get_r_and_s_from_sig_string, der_sig_from_sig_string
 from . import constants
@@ -484,38 +483,32 @@ class Peer(Logger):
         return bool(self.features & LnFeatures.OPTION_STATIC_REMOTEKEY_OPT)
 
     def make_local_config(self, funding_sat: int, push_msat: int, initiator: HTLCOwner) -> LocalConfig:
-        # key derivation
-        seed = os.urandom(32)
-        node = BIP32Node.from_rootseed(seed, xtype='standard')
-        keypair_generator = lambda family: generate_keypair(node, family)
 
+        random_seed = os.urandom(32)
         if initiator == LOCAL:
             initial_msat = funding_sat * 1000 - push_msat
         else:
             initial_msat = push_msat
 
         if self.is_static_remotekey():
+            # Note: in the future, if a CSV delay is added,
+            # we will want to derive that key
             wallet = self.lnworker.wallet
             assert wallet.txin_type == 'p2wpkh'
             addr = wallet.get_unused_address()
-            static_key = wallet.get_public_key(addr) # just a pubkey
+            static_remotekey = bfh(wallet.get_public_key(addr))
-            payment_basepoint = OnlyPubkeyKeypair(bfh(static_key))
         else:
-            payment_basepoint = keypair_generator(LnKeyFamily.PAYMENT_BASE)
+            static_remotekey = None
 
-        local_config=LocalConfig(
+        local_config = LocalConfig.from_seed(
-            payment_basepoint=payment_basepoint,
+            seed=random_seed,
-            multisig_key=keypair_generator(LnKeyFamily.MULTISIG),
+            static_remotekey=static_remotekey,
-            htlc_basepoint=keypair_generator(LnKeyFamily.HTLC_BASE),
-            delayed_basepoint=keypair_generator(LnKeyFamily.DELAY_BASE),
-            revocation_basepoint=keypair_generator(LnKeyFamily.REVOCATION_BASE),
             to_self_delay=DEFAULT_TO_SELF_DELAY,
             dust_limit_sat=546,
             max_htlc_value_in_flight_msat=funding_sat * 1000,
             max_accepted_htlcs=5,
             initial_msat=initial_msat,
             reserve_sat=546,
-            per_commitment_secret_seed=keypair_generator(LnKeyFamily.REVOCATION_ROOT).privkey,
             funding_locked_received=False,
             was_announced=False,
             current_commitment_signature=None,

electrum/lnutil.py

@@ -77,11 +77,27 @@ class Config(StoredObject):
 
 @attr.s
 class LocalConfig(Config):
-    per_commitment_secret_seed = attr.ib(type=bytes, converter=hex_to_bytes)
+    seed = attr.ib(type=bytes, converter=hex_to_bytes)
     funding_locked_received = attr.ib(type=bool)
     was_announced = attr.ib(type=bool)
     current_commitment_signature = attr.ib(type=bytes, converter=hex_to_bytes)
     current_htlc_signatures = attr.ib(type=bytes, converter=hex_to_bytes)
+    per_commitment_secret_seed = attr.ib(type=bytes, converter=hex_to_bytes)
+
+    @classmethod
+    def from_seed(self, **kwargs):
+        seed = kwargs['seed']
+        static_remotekey = kwargs.pop('static_remotekey')
+        node = BIP32Node.from_rootseed(seed, xtype='standard')
+        keypair_generator = lambda family: generate_keypair(node, family)
+        kwargs['per_commitment_secret_seed'] = keypair_generator(LnKeyFamily.REVOCATION_ROOT).privkey
+        kwargs['multisig_key'] = keypair_generator(LnKeyFamily.MULTISIG)
+        kwargs['htlc_basepoint'] = keypair_generator(LnKeyFamily.HTLC_BASE)
+        kwargs['delayed_basepoint'] = keypair_generator(LnKeyFamily.DELAY_BASE)
+        kwargs['revocation_basepoint'] = keypair_generator(LnKeyFamily.REVOCATION_BASE)
+        kwargs['payment_basepoint'] = OnlyPubkeyKeypair(static_remotekey) if static_remotekey else keypair_generator(LnKeyFamily.PAYMENT_BASE)
+        return LocalConfig(**kwargs)
+
 
 @attr.s
 class RemoteConfig(Config):

electrum/tests/test_lnchannel.py

@@ -70,6 +70,7 @@ def create_channel_state(funding_txid, funding_index, funding_sat, is_initiator,
                 current_per_commitment_point=cur,
             ),
             "local_config":lnpeer.LocalConfig(
+                seed = None,
                 payment_basepoint=privkeys[0],
                 multisig_key=privkeys[1],
                 htlc_basepoint=privkeys[2],

electrum/wallet_db.py

@@ -50,7 +50,7 @@ if TYPE_CHECKING:
 
 OLD_SEED_VERSION = 4        # electrum versions < 2.0
 NEW_SEED_VERSION = 11       # electrum versions >= 2.0
-FINAL_SEED_VERSION = 27     # electrum >= 2.7 will set this to prevent
+FINAL_SEED_VERSION = 28     # electrum >= 2.7 will set this to prevent
                             # old versions from overwriting new format
 
 
@@ -173,6 +173,7 @@ class WalletDB(JsonDB):
         self._convert_version_25()
         self._convert_version_26()
         self._convert_version_27()
+        self._convert_version_28()
         self.put('seed_version', FINAL_SEED_VERSION)  # just to be sure
 
         self._after_upgrade_tasks()
@@ -596,6 +597,14 @@ class WalletDB(JsonDB):
             c['local_config']['htlc_minimum_msat'] = 1
         self.data['seed_version'] = 27
 
+    def _convert_version_28(self):
+        if not self._is_upgrade_method_needed(27, 27):
+            return
+        channels = self.data.get('channels', {})
+        for channel_id, c in channels.items():
+            c['local_config']['seed'] = None
+        self.data['seed_version'] = 28
+
     def _convert_imported(self):
         if not self._is_upgrade_method_needed(0, 13):
             return