persist channel db on disk. verify channel gossip sigs.

electrum/constants.py

@@ -27,6 +27,7 @@ import os
 import json
 
 from .util import inv_dict
+from . import bitcoin
 
 
 def read_json(filename, default):
@@ -49,6 +50,10 @@ class AbstractNet:
     def max_checkpoint(cls) -> int:
         return max(0, len(cls.CHECKPOINTS) * 2016 - 1)
 
+    @classmethod
+    def rev_genesis_bytes(cls) -> bytes:
+        return bytes.fromhex(bitcoin.rev_hex(cls.GENESIS))
+
 
 class BitcoinMainnet(AbstractNet):