116 lines
4.0 KiB
Python
116 lines
4.0 KiB
Python
#-*- coding: utf-8 -*-
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'''
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Copyright (c) 2016 NSR (National Security Research Institute)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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'''
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from .lsh_digest import LSHDigest
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## HMAC 구현 클래스
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class HmacLSH:
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__IPAD = 0x36
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__OPAD = 0x5c
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#__md = None
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__blocksize = 0
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__i_key_pad = None
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__o_key_pad = None
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__outlenbits = 0
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## 생성자
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# @param [in] self 객체 포인터
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# @param [in] wordlenbits 워드 길이 256, 512 중 하나여야 함
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# @param [in] outlenbits 출력 해시 길이 1 ~ wordlenbits 사이의 값이어야 함
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def __init__(self, wordlenbits, outlenbits = 0):
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self.__outlenbits = outlenbits
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if outlenbits > 0:
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self.__md = LSHDigest.getInstance(wordlenbits, outlenbits)
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else:
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self.__md = LSHDigest.getInstance(wordlenbits)
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self.__blocksize = self.__md.get_blocksize()
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## HMAC 계산을 위한 초기화
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# @param [in] self 객체 포인터
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# @param [in] key 키
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def init(self, key):
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if key is None:
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key = bytearray([0] * self._blocksize)
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if len(key) > self.__blocksize:
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self.__md.reset()
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key = self.__md.final(key)
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self.__i_key_pad = [HmacLSH.__IPAD] * self.__blocksize
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self.__o_key_pad = [HmacLSH.__OPAD] * self.__blocksize
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for idx in range(len(key)):
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self.__i_key_pad[idx] ^= key[idx]
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self.__o_key_pad[idx] ^= key[idx]
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self.reset()
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## 새로운 HMAC을 계산할 수 있도록 객체를 초기화한다
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# @param [in] self 객체 포인터
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def reset(self):
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self.__md.reset()
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self.__md.update(self.__i_key_pad)
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## HMAC을 계산할 메시지를 추가한다.
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# @param [in] self 객체 포인터
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# @param [in] msg 입력 메시지
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def update(self, msg):
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if msg is None:
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return
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self.__md.update(msg)
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## HMAC을 계산하고 결과를 리턴한다.
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# @param [in] self 객체 포인터
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# @return 계산된 HMAC 값
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def final(self):
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result = self.__md.final()
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self.__md.update(self.__o_key_pad)
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self.__md.update(result)
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result = self.__md.final()
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self.reset()
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return result
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## digest 함수 - 최종 해쉬값을 계산하여 리턴한다.
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# @param [in] wordlenbits 워드 길이 256, 512 중 하나여야 함
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# @param [in] outlenbits 출력 해시 길이 1 ~ wordlenbits 사이의 값이어야 함
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# @param [in] key HMAC key
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# @param [in] data 입력 데이터
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# @param [in] offset 데이터 시작 오프셋 (바이트)
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# @param [in] length 데이터 길이 (비트)
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# @return 계산된 HMAC값
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@staticmethod
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def digest(wordlenbits, outlenbits = None, key = None, data = None, offset = 0, length = -1):
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hmac = HmacLSH(wordlenbits, outlenbits)
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hmac.init(key)
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hmac.update(data, offset, length)
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return hmac.final()
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