55 lines
1.2 KiB
C++
55 lines
1.2 KiB
C++
// tea.cpp - modified by Wei Dai from code in the original paper
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#include "pch.h"
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#include "tea.h"
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#include "misc.h"
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NAMESPACE_BEGIN(CryptoPP)
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const word32 TEA::Base::DELTA = 0x9e3779b9;
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void TEA::Base::UncheckedSetKey(CipherDir direction, const byte *userKey, unsigned int length)
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{
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AssertValidKeyLength(length);
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GetUserKey(BIG_ENDIAN_ORDER, k.begin(), 4, userKey, KEYLENGTH);
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}
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typedef BlockGetAndPut<word32, BigEndian> Block;
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void TEA::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
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{
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word32 y, z;
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Block::Get(inBlock)(y)(z);
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word32 sum = 0;
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for (int i=0; i<ROUNDS; i++)
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{
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sum += DELTA;
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y += (z << 4) + k[0] ^ z + sum ^ (z >> 5) + k[1];
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z += (y << 4) + k[2] ^ y + sum ^ (y >> 5) + k[3];
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}
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Block::Put(xorBlock, outBlock)(y)(z);
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}
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typedef BlockGetAndPut<word32, BigEndian> Block;
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void TEA::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
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{
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word32 y, z;
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Block::Get(inBlock)(y)(z);
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word32 sum = DELTA << LOG_ROUNDS;
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for (int i=0; i<ROUNDS; i++)
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{
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z -= (y << 4) + k[2] ^ y + sum ^ (y >> 5) + k[3];
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y -= (z << 4) + k[0] ^ z + sum ^ (z >> 5) + k[1];
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sum -= DELTA;
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}
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Block::Put(xorBlock, outBlock)(y)(z);
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}
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NAMESPACE_END
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