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-rw-r--r--test/functional/test_framework/segwit_addr.py107
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diff --git a/test/functional/test_framework/segwit_addr.py b/test/functional/test_framework/segwit_addr.py
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+++ b/test/functional/test_framework/segwit_addr.py
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+#!/usr/bin/env python3
+# 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."""
+
+
+CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+
+
+def bech32_polymod(values):
+ """Internal function that computes the Bech32 checksum."""
+ generator = [0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3]
+ chk = 1
+ for value in values:
+ top = chk >> 25
+ chk = (chk & 0x1ffffff) << 5 ^ value
+ for i in range(5):
+ chk ^= generator[i] if ((top >> i) & 1) else 0
+ return chk
+
+
+def bech32_hrp_expand(hrp):
+ """Expand the HRP into values for checksum computation."""
+ return [ord(x) >> 5 for x in hrp] + [0] + [ord(x) & 31 for x in 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
+
+
+def bech32_create_checksum(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
+ 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)
+ return hrp + '1' + ''.join([CHARSET[d] for d in combined])
+
+
+def bech32_decode(bech):
+ """Validate a Bech32 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)
+ bech = bech.lower()
+ pos = bech.rfind('1')
+ if pos < 1 or pos + 7 > len(bech) or len(bech) > 90:
+ return (None, None)
+ if not all(x in CHARSET for x in bech[pos+1:]):
+ return (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])
+
+
+def convertbits(data, frombits, tobits, pad=True):
+ """General power-of-2 base conversion."""
+ acc = 0
+ bits = 0
+ ret = []
+ maxv = (1 << tobits) - 1
+ max_acc = (1 << (frombits + tobits - 1)) - 1
+ for value in data:
+ if value < 0 or (value >> frombits):
+ return None
+ acc = ((acc << frombits) | value) & max_acc
+ bits += frombits
+ while bits >= tobits:
+ bits -= tobits
+ ret.append((acc >> bits) & maxv)
+ if pad:
+ if bits:
+ ret.append((acc << (tobits - bits)) & maxv)
+ elif bits >= frombits or ((acc << (tobits - bits)) & maxv):
+ return None
+ return ret
+
+
+def decode(hrp, addr):
+ """Decode a segwit address."""
+ hrpgot, data = bech32_decode(addr)
+ if hrpgot != hrp:
+ return (None, None)
+ decoded = convertbits(data[1:], 5, 8, False)
+ if decoded is None or len(decoded) < 2 or len(decoded) > 40:
+ return (None, None)
+ if data[0] > 16:
+ return (None, None)
+ if data[0] == 0 and len(decoded) != 20 and len(decoded) != 32:
+ return (None, None)
+ return (data[0], decoded)
+
+
+def encode(hrp, witver, witprog):
+ """Encode a segwit address."""
+ ret = bech32_encode(hrp, [witver] + convertbits(witprog, 8, 5))
+ if decode(hrp, ret) == (None, None):
+ return None
+ return ret