lightning: scalarmult result is just a hash, not pubkey

lib/lightning.py

@@ -454,7 +454,7 @@ def SignOutputRaw(json):
     req = rpc_pb2.SignOutputRawRequest()
     json_format.Parse(json, req)
 
-    assert len(req.signDesc.pubKey) in [33, 0]
+    #assert len(req.signDesc.pubKey) in [33, 0]
     assert len(req.signDesc.doubleTweak) in [32, 0]
     assert len(req.signDesc.sigHashes.hashPrevOuts) == 64
     assert len(req.signDesc.sigHashes.hashSequence) == 64
@@ -469,11 +469,8 @@ def SignOutputRaw(json):
 
 
 def signOutputRaw(tx, signDesc):
-    adr = None
-    if len(signDesc.pubKey) != 0:
-       adr = bitcoin.pubkey_to_address('p2wpkh', binascii.hexlify(
-           signDesc.keyDescriptor.pubKey).decode("utf-8"))  # Because this is all NewAddress supports
-    pri = fetchPrivKey(adr, signDesc.keyDescriptor.keyLocator.family, signDesc.keyDescriptor.keyLocator.index)
+    pri = derivePrivKey(signDesc.keyDescriptor)
+    assert pri is not None
     pri2 = maybeTweakPrivKey(signDesc, pri)
     sig = rawTxInWitnessSignature(tx, signDesc.sigHashes, signDesc.inputIndex,
                                   signDesc.output.value, signDesc.witnessScript, sigHashAll, pri2)
@@ -523,35 +520,30 @@ def ComputeInputScript(json):
     return msg
 
 
-def fetchPrivKey(str_address, keyLocatorFamily, keyLocatorIndex, privKey=None):
+def fetchPrivKey(str_address, keyLocatorFamily, keyLocatorIndex):
     pri = None
 
     if str_address is not None:
-        assert privKey is None
         pri, redeem_script = WALLET.export_private_key(str_address, None)
 
         if redeem_script:
             print("ignoring redeem script", redeem_script)
 
         typ, pri, compressed = bitcoin.deserialize_privkey(pri)
+        if keyLocatorFamily == 0 and keyLocatorIndex == 0: return EC_KEY(pri)
 
         ks = keystore.BIP32_KeyStore({})
         der = "m/0'/"
         xtype = 'p2wpkh'
-        ks.add_xprv_from_seed(int.from_bytes(pri, "big"), xtype, der)
-    elif privKey is not None:
-        ks = keystore.BIP32_KeyStore({})
-        der = "m/0'/"
-        xtype = 'p2wpkh'
-        ks.add_xprv_from_seed(privKey.secret.to_bytes(32, 'big'), xtype, der)
+        ks.add_xprv_from_seed(pri, xtype, der)
     else:
         ks = WALLET.keystore
 
-    if keyLocatorFamily is not None or keyLocatorIndex is not None:
+    if keyLocatorFamily != 0 or keyLocatorIndex != 0:
         pri = ks.get_private_key([1017, keyLocatorFamily, keyLocatorIndex], password=None)[0]
         pri = EC_KEY(pri)
-    else:
-        pri = privKey
+
+    assert pri is not None
 
     return pri
 
@@ -801,6 +793,7 @@ async def readReqAndReply(obj, writer):
         await writer.drain()
 
 def privKeyForPubKey(pubKey):
+    global globalIdx
     priv_keys = WALLET.storage.get("lightning_extra_keys", [])
     for i in priv_keys:
         candidate = EC_KEY(i.to_bytes(32, "big"))
@@ -822,21 +815,20 @@ def privKeyForPubKey(pubKey):
         print("ignoring redeem script", redeem_script)
 
     typ, pri, compressed = bitcoin.deserialize_privkey(pri)
-    return EC_KEY(pri.to_bytes(32, "big"))
+    return EC_KEY(pri)
     
     #assert False, "could not find private key for pubkey {} hex={}".format(pubKey, binascii.hexlify(pubKey).decode("ascii"))
 
 def derivePrivKey(keyDesc):
-    global globalIdx
     keyDescFam = keyDesc.keyLocator.family
     keyDescIdx = keyDesc.keyLocator.index
     keyDescPubKey = keyDesc.pubKey
     privKey = None
 
     if len(keyDescPubKey) != 0:
-       privKey = privKeyForPubKey(keyDescPubKey)
+        return privKeyForPubKey(keyDescPubKey)
 
-    return fetchPrivKey(None, keyDescFam, keyDescIdx, privKey)
+    return fetchPrivKey(None, keyDescFam, keyDescIdx)
 
 def DerivePrivKey(json):
     req = rpc_pb2.DerivePrivKeyRequest()
@@ -911,7 +903,7 @@ def ScalarMult(json):
 
     m = rpc_pb2.ScalarMultResponse()
 
-    m.pubKey = pubkFromECKEY(EC_KEY(c.digest()))
+    m.hashResult = c.digest()
 
     msg = json_format.MessageToJson(m)
     return msg