44 lines
1.1 KiB
Python
44 lines
1.1 KiB
Python
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import sys
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# python2/3 compatibility
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if sys.version > '3':
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byte2int = lambda x: x
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else:
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byte2int = ord
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def remove_pkcs5_padding(data):
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padding_length = byte2int(data[-1])
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return data[:-padding_length]
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def add_pkcs5_padding(data, blocksize):
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last_block_len = len(data) % blocksize
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padding_length = blocksize - last_block_len
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if padding_length == 0:
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padding_length = blocksize
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return data + bytes(bytearray([padding_length] * padding_length))
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# algorithm taken from msdn documentation for CryptDeriveKey
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def derive_key_3des_aes(hash_alg):
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from wincrypto.api import CryptCreateHash
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buf1 = bytearray(b'\x36' * 64)
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hash_val = bytearray(hash_alg.get_hash_val())
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for x in range(len(hash_val)):
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buf1[x] ^= hash_val[x]
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buf2 = bytearray(b'\x5c' * 64)
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for x in range(len(hash_val)):
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buf2[x] ^= hash_val[x]
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hash1 = CryptCreateHash(hash_alg.alg_id)
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hash1.hash_data(bytes(buf1))
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hash2 = CryptCreateHash(hash_alg.alg_id)
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hash2.hash_data(bytes(buf2))
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derived_key = hash1.get_hash_val() + hash2.get_hash_val()
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return derived_key
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def GET_ALG_CLASS(x):
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return x & (7 << 13)
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