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-rw-r--r--src/ssh_audit/ssh1_crc32.py47
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diff --git a/src/ssh_audit/ssh1_crc32.py b/src/ssh_audit/ssh1_crc32.py
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+++ b/src/ssh_audit/ssh1_crc32.py
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+"""
+ 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