Use Bech32m encoding for v1+ segwit addresses

This also includes updates to the Python test framework implementation,
test vectors, and release notes.

3 files changed, 60 insertions, 24 deletions

diff --git a/test/functional/rpc_invalid_address_message.py b/test/functional/rpc_invalid_address_message.py
index 469d6bdb05..e362642f0f 100755
--- a/test/functional/rpc_invalid_address_message.py
+++ b/test/functional/rpc_invalid_address_message.py
@@ -12,8 +12,12 @@ from test_framework.util import (
 )
 
 BECH32_VALID = 'bcrt1qtmp74ayg7p24uslctssvjm06q5phz4yrxucgnv'
-BECH32_INVALID_SIZE = 'bcrt1sqqpl9r5c'
-BECH32_INVALID_PREFIX = 'bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4'
+BECH32_INVALID_BECH32 = 'bcrt1p0xlxvlhemja6c4dqv22uapctqupfhlxm9h8z3k2e72q4k9hcz7vqdmchcc'
+BECH32_INVALID_BECH32M = 'bcrt1qw508d6qejxtdg4y5r3zarvary0c5xw7k35mrzd'
+BECH32_INVALID_VERSION = 'bcrt130xlxvlhemja6c4dqv22uapctqupfhlxm9h8z3k2e72q4k9hcz7vqynjegk'
+BECH32_INVALID_SIZE = 'bcrt1s0xlxvlhemja6c4dqv22uapctqupfhlxm9h8z3k2e72q4k9hcz7v8n0nx0muaewav25430mtr'
+BECH32_INVALID_V0_SIZE = 'bcrt1qw508d6qejxtdg4y5r3zarvary0c5xw7kqqq5k3my'
+BECH32_INVALID_PREFIX = 'bc1pw508d6qejxtdg4y5r3zarvary0c5xw7kw508d6qejxtdg4y5r3zarvary0c5xw7k7grplx'
 
 BASE58_VALID = 'mipcBbFg9gMiCh81Kj8tqqdgoZub1ZJRfn'
 BASE58_INVALID_PREFIX = '17VZNX1SN5NtKa8UQFxwQbFeFc3iqRYhem'
@@ -40,6 +44,18 @@ class InvalidAddressErrorMessageTest(BitcoinTestFramework):
         assert not info['isvalid']
         assert_equal(info['error'], 'Invalid prefix for Bech32 address')
 
+        info = node.validateaddress(BECH32_INVALID_BECH32)
+        assert not info['isvalid']
+        assert_equal(info['error'], 'Version 1+ witness address must use Bech32m checksum')
+
+        info = node.validateaddress(BECH32_INVALID_BECH32M)
+        assert not info['isvalid']
+        assert_equal(info['error'], 'Version 0 witness address must use Bech32 checksum')
+
+        info = node.validateaddress(BECH32_INVALID_V0_SIZE)
+        assert not info['isvalid']
+        assert_equal(info['error'], 'Invalid Bech32 v0 address data size')
+
         info = node.validateaddress(BECH32_VALID)
         assert info['isvalid']
         assert 'error' not in info
diff --git a/test/functional/test_framework/segwit_addr.py b/test/functional/test_framework/segwit_addr.py
index 00c0d8a919..861ca2b949 100644
--- a/test/functional/test_framework/segwit_addr.py
+++ b/test/functional/test_framework/segwit_addr.py
@@ -2,10 +2,18 @@
 # Copyright (c) 2017 Pieter Wuille
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
-"""Reference implementation for Bech32 and segwit addresses."""
+"""Reference implementation for Bech32/Bech32m and segwit addresses."""
 import unittest
+from enum import Enum
 
 CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+BECH32_CONST = 1
+BECH32M_CONST = 0x2bc830a3
+
+class Encoding(Enum):
+    """Enumeration type to list the various supported encodings."""
+    BECH32 = 1
+    BECH32M = 2
 
 
 def bech32_polymod(values):
@@ -27,38 +35,45 @@ def bech32_hrp_expand(hrp):
 
 def bech32_verify_checksum(hrp, data):
     """Verify a checksum given HRP and converted data characters."""
-    return bech32_polymod(bech32_hrp_expand(hrp) + data) == 1
-
+    check = bech32_polymod(bech32_hrp_expand(hrp) + data)
+    if check == BECH32_CONST:
+        return Encoding.BECH32
+    elif check == BECH32M_CONST:
+        return Encoding.BECH32M
+    else:
+        return None
 
-def bech32_create_checksum(hrp, data):
+def bech32_create_checksum(encoding, hrp, data):
     """Compute the checksum values given HRP and data."""
     values = bech32_hrp_expand(hrp) + data
-    polymod = bech32_polymod(values + [0, 0, 0, 0, 0, 0]) ^ 1
+    const = BECH32M_CONST if encoding == Encoding.BECH32M else BECH32_CONST
+    polymod = bech32_polymod(values + [0, 0, 0, 0, 0, 0]) ^ const
     return [(polymod >> 5 * (5 - i)) & 31 for i in range(6)]
 
 
-def bech32_encode(hrp, data):
-    """Compute a Bech32 string given HRP and data values."""
-    combined = data + bech32_create_checksum(hrp, data)
+def bech32_encode(encoding, hrp, data):
+    """Compute a Bech32 or Bech32m string given HRP and data values."""
+    combined = data + bech32_create_checksum(encoding, hrp, data)
     return hrp + '1' + ''.join([CHARSET[d] for d in combined])
 
 
 def bech32_decode(bech):
-    """Validate a Bech32 string, and determine HRP and data."""
+    """Validate a Bech32/Bech32m string, and determine HRP and data."""
     if ((any(ord(x) < 33 or ord(x) > 126 for x in bech)) or
             (bech.lower() != bech and bech.upper() != bech)):
-        return (None, None)
+        return (None, None, None)
     bech = bech.lower()
     pos = bech.rfind('1')
     if pos < 1 or pos + 7 > len(bech) or len(bech) > 90:
-        return (None, None)
+        return (None, None, None)
     if not all(x in CHARSET for x in bech[pos+1:]):
-        return (None, None)
+        return (None, None, None)
     hrp = bech[:pos]
     data = [CHARSET.find(x) for x in bech[pos+1:]]
-    if not bech32_verify_checksum(hrp, data):
-        return (None, None)
-    return (hrp, data[:-6])
+    encoding = bech32_verify_checksum(hrp, data)
+    if encoding is None:
+        return (None, None, None)
+    return (encoding, hrp, data[:-6])
 
 
 def convertbits(data, frombits, tobits, pad=True):
@@ -86,7 +101,7 @@ def convertbits(data, frombits, tobits, pad=True):
 
 def decode_segwit_address(hrp, addr):
     """Decode a segwit address."""
-    hrpgot, data = bech32_decode(addr)
+    encoding, hrpgot, data = bech32_decode(addr)
     if hrpgot != hrp:
         return (None, None)
     decoded = convertbits(data[1:], 5, 8, False)
@@ -96,12 +111,15 @@ def decode_segwit_address(hrp, addr):
         return (None, None)
     if data[0] == 0 and len(decoded) != 20 and len(decoded) != 32:
         return (None, None)
+    if (data[0] == 0 and encoding != Encoding.BECH32) or (data[0] != 0 and encoding != Encoding.BECH32M):
+        return (None, None)
     return (data[0], decoded)
 
 
 def encode_segwit_address(hrp, witver, witprog):
     """Encode a segwit address."""
-    ret = bech32_encode(hrp, [witver] + convertbits(witprog, 8, 5))
+    encoding = Encoding.BECH32 if witver == 0 else Encoding.BECH32M
+    ret = bech32_encode(encoding, hrp, [witver] + convertbits(witprog, 8, 5))
     if decode_segwit_address(hrp, ret) == (None, None):
         return None
     return ret
@@ -119,3 +137,5 @@ class TestFrameworkScript(unittest.TestCase):
         # P2WSH
         test_python_bech32('bcrt1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq3xueyj')
         test_python_bech32('bcrt1qft5p2uhsdcdc3l2ua4ap5qqfg4pjaqlp250x7us7a8qqhrxrxfsqseac85')
+        # P2TR
+        test_python_bech32('bcrt1p0xlxvlhemja6c4dqv22uapctqupfhlxm9h8z3k2e72q4k9hcz7vqc8gma6')
diff --git a/test/functional/wallet_labels.py b/test/functional/wallet_labels.py
index 883b97561e..551eb72720 100755
--- a/test/functional/wallet_labels.py
+++ b/test/functional/wallet_labels.py
@@ -138,13 +138,13 @@ class WalletLabelsTest(BitcoinTestFramework):
         node.createwallet(wallet_name='watch_only', disable_private_keys=True)
         wallet_watch_only = node.get_wallet_rpc('watch_only')
         BECH32_VALID = {
-            '✔️_VER15_PROG40': 'bcrt10qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqn2cjv3',
-            '✔️_VER16_PROG03': 'bcrt1sqqqqqjq8pdp',
-            '✔️_VER16_PROB02': 'bcrt1sqqqqqjq8pv',
+            '✔️_VER15_PROG40': 'bcrt10qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqxkg7fn',
+            '✔️_VER16_PROG03': 'bcrt1sqqqqq8uhdgr',
+            '✔️_VER16_PROB02': 'bcrt1sqqqq4wstyw',
         }
         BECH32_INVALID = {
-            '❌_VER15_PROG41': 'bcrt10qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqzc7xyq',
-            '❌_VER16_PROB01': 'bcrt1sqqpl9r5c',
+            '❌_VER15_PROG41': 'bcrt1sqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqajlxj8',
+            '❌_VER16_PROB01': 'bcrt1sqq5r4036',
         }
         for l in BECH32_VALID:
             ad = BECH32_VALID[l]