From c3cff91fcadb240a82d2e5ae9789a89df299bdc7 Mon Sep 17 00:00:00 2001
From: tecnovert <tecnovert@tecnovert.net>
Date: Tue, 19 Jan 2021 15:10:42 +0200
Subject: [PATCH] Raise version. Verify message with coincurve.

---
 basicswap/__init__.py      |  2 +-
 basicswap/basicswap.py     |  2 +-
 basicswap/interface_btc.py | 24 +++++++++++++++++++++++-
 basicswap/util.py          | 35 ++++++++++++++++++++++++-----------
 4 files changed, 49 insertions(+), 14 deletions(-)

diff --git a/basicswap/__init__.py b/basicswap/__init__.py
index 338d8c4..cd29f0e 100644
--- a/basicswap/__init__.py
+++ b/basicswap/__init__.py
@@ -1,3 +1,3 @@
 name = "basicswap"
 
-__version__ = "0.0.11"
+__version__ = "0.0.12"
diff --git a/basicswap/basicswap.py b/basicswap/basicswap.py
index d10409e..a4c8472 100644
--- a/basicswap/basicswap.py
+++ b/basicswap/basicswap.py
@@ -3523,7 +3523,7 @@ class BasicSwap(BaseApp):
             # Verify proof of funds
             bid_proof_address = replaceAddrPrefix(bid_data.proof_address, Coins.PART, self.chain)
             mm = chainparams[coin_to]['message_magic']
-            passed = self.callcoinrpc(Coins.PART, 'verifymessage', [bid_proof_address, bid_data.proof_signature, bid_data.proof_address + '_swap_proof', mm])
+            passed = self.ci(Coins.PART).verifyMessage(bid_proof_address, bid_data.proof_address + '_swap_proof', bid_data.proof_signature, mm)
             assert(passed is True), 'Proof of funds signature invalid'
 
             if self.coin_clients[coin_to]['use_segwit']:
diff --git a/basicswap/interface_btc.py b/basicswap/interface_btc.py
index 73db051..d601538 100644
--- a/basicswap/interface_btc.py
+++ b/basicswap/interface_btc.py
@@ -6,6 +6,7 @@
 # file LICENSE or http://www.opensource.org/licenses/mit-license.php.
 
 import time
+import base64
 import hashlib
 import logging
 from io import BytesIO
@@ -14,10 +15,12 @@ from basicswap.contrib.test_framework import segwit_addr
 from .util import (
     decodeScriptNum,
     getCompactSizeLen,
+    SerialiseNumCompact,
     dumpj,
     format_amount,
     make_int,
     toWIF,
+    assert_cond,
     decodeAddress)
 from coincurve.keys import (
     PrivateKey,
@@ -61,7 +64,6 @@ from .contrib.test_framework.script import (
 
 from .chainparams import CoinInterface, Coins, chainparams
 from .rpc import make_rpc_func
-from .util import assert_cond
 
 
 def findOutput(tx, script_pk):
@@ -859,6 +861,26 @@ class BTCInterface(CoinInterface):
         rv = pubkey.verify_compact(sig, message_hash, hasher=None)
         assert(rv is True)
 
+    def verifyMessage(self, address, message, signature, message_magic=None):
+        if message_magic is None:
+            message_magic = chainparams[self.coin_type()]['message_magic']
+
+        message_bytes = SerialiseNumCompact(len(message_magic)) + bytes(message_magic, 'utf-8') + SerialiseNumCompact(len(message)) + bytes(message, 'utf-8')
+        message_hash = hashlib.sha256(hashlib.sha256(message_bytes).digest()).digest()
+        signature_bytes = base64.b64decode(signature)
+        rec_id = (signature_bytes[0] - 27) & 3
+        signature_bytes = signature_bytes[1:] + bytes((rec_id,))
+        try:
+            pubkey = PublicKey.from_signature_and_message(signature_bytes, message_hash, hasher=None)
+        except Exception as e:
+            logging.info('verifyMessage failed: ' + str(e))
+            return False
+
+        address_hash = self.decodeAddress(address)
+        pubkey_hash = hash160(pubkey.format())
+
+        return True if address_hash == pubkey_hash else False
+
 
 def testBTCInterface():
     print('testBTCInterface')
diff --git a/basicswap/util.py b/basicswap/util.py
index 4572775..1cc653c 100644
--- a/basicswap/util.py
+++ b/basicswap/util.py
@@ -7,6 +7,7 @@
 
 import json
 import time
+import struct
 import decimal
 import hashlib
 
@@ -113,9 +114,9 @@ def decodeWif(network_key):
 
 
 def toWIF(prefix_byte, b, compressed=True):
-    b = bytes((prefix_byte, )) + b
+    b = bytes((prefix_byte,)) + b
     if compressed:
-        b += bytes((0x01, ))
+        b += bytes((0x01,))
     b += hashlib.sha256(hashlib.sha256(b).digest()).digest()[:4]
     return b58encode(b)
 
@@ -163,9 +164,9 @@ def pubkeyToAddress(prefix, pubkey):
 
 def SerialiseNum(n):
     if n == 0:
-        return bytes([0x00])
+        return bytes((0x00,))
     if n > 0 and n <= 16:
-        return bytes([0x50 + n])
+        return bytes((0x50 + n,))
     rv = bytearray()
     neg = n < 0
     absvalue = -n if neg else n
@@ -176,7 +177,7 @@ def SerialiseNum(n):
         rv.append(0x80 if neg else 0)
     elif neg:
         rv[-1] |= 0x80
-    return bytes([len(rv)]) + rv
+    return bytes((len(rv),)) + rv
 
 
 def DeserialiseNum(b, o=0):
@@ -222,15 +223,27 @@ def getCompactSizeLen(v):
     # Compact Size
     if v < 253:
         return 1
-    if v < 0xffff:  # USHRT_MAX
+    if v <= 0xffff:  # USHRT_MAX
         return 3
-    if v < 0xffffffff:  # UINT_MAX
+    if v <= 0xffffffff:  # UINT_MAX
         return 5
-    if v < 0xffffffffffffffff:  # UINT_MAX
+    if v <= 0xffffffffffffffff:  # UINT_MAX
         return 9
     raise ValueError('Value too large')
 
 
+def SerialiseNumCompact(v):
+    if v < 253:
+        return bytes((v,))
+    if v <= 0xffff:  # USHRT_MAX
+        return struct.pack("<BH", 253, v)
+    if v <= 0xffffffff:  # UINT_MAX
+        return struct.pack("<BI", 254, v)
+    if v <= 0xffffffffffffffff:  # UINT_MAX
+        return struct.pack("<BQ", 255, v)
+    raise ValueError('Value too large')
+
+
 def float_to_str(f):
     # stackoverflow.com/questions/38847690
     d1 = decimal_ctx.create_decimal(repr(f))
@@ -314,10 +327,10 @@ def format_timestamp(value, with_seconds=False):
 
 
 def getP2SHScriptForHash(p2sh):
-    return bytes([OpCodes.OP_HASH160, 0x14]) \
+    return bytes((OpCodes.OP_HASH160, 0x14)) \
         + p2sh \
-        + bytes([OpCodes.OP_EQUAL])
+        + bytes((OpCodes.OP_EQUAL,))
 
 
 def getP2WSH(script):
-    return bytes([OpCodes.OP_0, 0x20]) + hashlib.sha256(script).digest()
+    return bytes((OpCodes.OP_0, 0x20)) + hashlib.sha256(script).digest()