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Diffstat (limited to 'src/ssh_audit/ssh1_crc32.py')
-rw-r--r-- | src/ssh_audit/ssh1_crc32.py | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/src/ssh_audit/ssh1_crc32.py b/src/ssh_audit/ssh1_crc32.py new file mode 100644 index 0000000..55089ed --- /dev/null +++ b/src/ssh_audit/ssh1_crc32.py @@ -0,0 +1,47 @@ +""" + The MIT License (MIT) + + Copyright (C) 2017 Andris Raugulis (moo@arthepsy.eu) + + Permission is hereby granted, free of charge, to any person obtaining a copy + of this software and associated documentation files (the "Software"), to deal + in the Software without restriction, including without limitation the rights + to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + copies of the Software, and to permit persons to whom the Software is + furnished to do so, subject to the following conditions: + + The above copyright notice and this permission notice shall be included in + all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + THE SOFTWARE. +""" +# pylint: disable=unused-import +from typing import Dict, List, Set, Sequence, Tuple, Iterable # noqa: F401 +from typing import Callable, Optional, Union, Any # noqa: F401 + + +class SSH1_CRC32: + def __init__(self) -> None: + self._table = [0] * 256 + for i in range(256): + crc = 0 + n = i + for _ in range(8): + x = (crc ^ n) & 1 + crc = (crc >> 1) ^ (x * 0xedb88320) + n = n >> 1 + self._table[i] = crc + + def calc(self, v: bytes) -> int: + crc, length = 0, len(v) + for i in range(length): + n = ord(v[i:i + 1]) + n = n ^ (crc & 0xff) + crc = (crc >> 8) ^ self._table[n] + return crc |