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author | Pieter Wuille <pieter.wuille@gmail.com> | 2019-02-06 18:08:21 -0800 |
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committer | Pieter Wuille <pieter.wuille@gmail.com> | 2019-02-15 22:36:05 -0800 |
commit | 3b40bff9880e9ae2817136b7d14989afccfc1937 (patch) | |
tree | 65325ad0dbdda14e32704dfff400196aa13d04b8 /test/functional/test_framework/descriptors.py | |
parent | 743c2f461c0e7c58b1e5c6ddfeaf4f0ff6e6ca85 (diff) | |
download | bitcoin-3b40bff9880e9ae2817136b7d14989afccfc1937.tar.xz |
Descriptor checksum
Diffstat (limited to 'test/functional/test_framework/descriptors.py')
-rw-r--r-- | test/functional/test_framework/descriptors.py | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/test/functional/test_framework/descriptors.py b/test/functional/test_framework/descriptors.py new file mode 100644 index 0000000000..29482ce01e --- /dev/null +++ b/test/functional/test_framework/descriptors.py @@ -0,0 +1,55 @@ +#!/usr/bin/env python3 +# Copyright (c) 2019 Pieter Wuille +# Distributed under the MIT software license, see the accompanying +# file COPYING or http://www.opensource.org/licenses/mit-license.php. +"""Utility functions related to output descriptors""" + +INPUT_CHARSET = "0123456789()[],'/*abcdefgh@:$%{}IJKLMNOPQRSTUVWXYZ&+-.;<=>?!^_|~ijklmnopqrstuvwxyzABCDEFGH`#\"\\ " +CHECKSUM_CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l" +GENERATOR = [0xf5dee51989, 0xa9fdca3312, 0x1bab10e32d, 0x3706b1677a, 0x644d626ffd] + +def descsum_polymod(symbols): + """Internal function that computes the descriptor checksum.""" + chk = 1 + for value in symbols: + top = chk >> 35 + chk = (chk & 0x7ffffffff) << 5 ^ value + for i in range(5): + chk ^= GENERATOR[i] if ((top >> i) & 1) else 0 + return chk + +def descsum_expand(s): + """Internal function that does the character to symbol expansion""" + groups = [] + symbols = [] + for c in s: + if not c in INPUT_CHARSET: + return None + v = INPUT_CHARSET.find(c) + symbols.append(v & 31) + groups.append(v >> 5) + if len(groups) == 3: + symbols.append(groups[0] * 9 + groups[1] * 3 + groups[2]) + groups = [] + if len(groups) == 1: + symbols.append(groups[0]) + elif len(groups) == 2: + symbols.append(groups[0] * 3 + groups[1]) + return symbols + +def descsum_create(s): + """Add a checksum to a descriptor without""" + symbols = descsum_expand(s) + [0, 0, 0, 0, 0, 0, 0, 0] + checksum = descsum_polymod(symbols) ^ 1 + return s + '#' + ''.join(CHECKSUM_CHARSET[(checksum >> (5 * (7 - i))) & 31] for i in range(8)) + +def descsum_check(s, require=True): + """Verify that the checksum is correct in a descriptor""" + if not '#' in s: + return not require + if s[-9] != '#': + return False + if not all(x in CHECKSUM_CHARSET for x in s[-8:]): + return False + symbols = descsum_expand(s[:-9]) + [CHECKSUM_CHARSET.find(x) for x in s[-8:]] + return descsum_polymod(symbols) == 1 |