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// tea.cpp - modified by Wei Dai from code in the original paper
#include "pch.h"
#include "tea.h"
#include "misc.h"
NAMESPACE_BEGIN(CryptoPP)
static const word32 DELTA = 0x9e3779b9;
typedef BlockGetAndPut<word32, BigEndian> Block;
#define UINT32_CAST(x) ((word32*)(void*)(x))
#define CONST_UINT32_CAST(x) ((const word32*)(const void*)(x))
void TEA::Base::UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs ¶ms)
{
AssertValidKeyLength(length);
GetUserKey(BIG_ENDIAN_ORDER, m_k.begin(), 4, userKey, KEYLENGTH);
m_limit = GetRoundsAndThrowIfInvalid(params, this) * DELTA;
}
void TEA::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
word32 y, z, sum = 0;
Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != m_limit)
{
sum += DELTA;
y += ((z << 4) + m_k[0]) ^ (z + sum) ^ ((z >> 5) + m_k[1]);
z += ((y << 4) + m_k[2]) ^ (y + sum) ^ ((y >> 5) + m_k[3]);
}
Block::Put(xorBlock, outBlock)(y)(z);
}
void TEA::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
word32 y, z, sum = m_limit;
Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != 0)
{
z -= ((y << 4) + m_k[2]) ^ (y + sum) ^ ((y >> 5) + m_k[3]);
y -= ((z << 4) + m_k[0]) ^ (z + sum) ^ ((z >> 5) + m_k[1]);
sum -= DELTA;
}
Block::Put(xorBlock, outBlock)(y)(z);
}
void XTEA::Base::UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs ¶ms)
{
AssertValidKeyLength(length);
GetUserKey(BIG_ENDIAN_ORDER, m_k.begin(), 4, userKey, KEYLENGTH);
m_limit = GetRoundsAndThrowIfInvalid(params, this) * DELTA;
}
void XTEA::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
word32 y, z, sum = 0;
Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != m_limit)
{
y += ((z<<4 ^ z>>5) + z) ^ (sum + m_k[sum&3]);
sum += DELTA;
z += ((y<<4 ^ y>>5) + y) ^ (sum + m_k[sum>>11 & 3]);
}
Block::Put(xorBlock, outBlock)(y)(z);
}
void XTEA::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
word32 y, z, sum = m_limit;
Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != 0)
{
z -= ((y<<4 ^ y>>5) + y) ^ (sum + m_k[sum>>11 & 3]);
sum -= DELTA;
y -= ((z<<4 ^ z>>5) + z) ^ (sum + m_k[sum&3]);
}
Block::Put(xorBlock, outBlock)(y)(z);
}
#define MX ((z>>5^y<<2)+(y>>3^z<<4))^((sum^y)+(m_k[(p&3)^e]^z))
void BTEA::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
CRYPTOPP_UNUSED(xorBlock);
CRYPTOPP_ASSERT(IsAlignedOn(inBlock,GetAlignmentOf<word32>()));
CRYPTOPP_ASSERT(IsAlignedOn(outBlock,GetAlignmentOf<word32>()));
unsigned int n = m_blockSize / 4;
word32 *v = UINT32_CAST(outBlock);
ConditionalByteReverse(BIG_ENDIAN_ORDER, v, CONST_UINT32_CAST(inBlock), m_blockSize);
word32 y, z = v[n-1], e;
word32 p, q = 6+52/n;
word32 sum = 0;
while (q-- > 0)
{
sum += DELTA;
e = sum>>2 & 3;
for (p = 0; p < n-1; p++)
{
y = v[p+1];
z = v[p] += MX;
}
y = v[0];
z = v[n-1] += MX;
}
ConditionalByteReverse(BIG_ENDIAN_ORDER, v, v, m_blockSize);
}
void BTEA::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
CRYPTOPP_UNUSED(xorBlock);
CRYPTOPP_ASSERT(IsAlignedOn(inBlock,GetAlignmentOf<word32>()));
CRYPTOPP_ASSERT(IsAlignedOn(outBlock,GetAlignmentOf<word32>()));
unsigned int n = m_blockSize / 4;
word32 *v = UINT32_CAST(outBlock);
ConditionalByteReverse(BIG_ENDIAN_ORDER, v, CONST_UINT32_CAST(inBlock), m_blockSize);
word32 y = v[0], z, e;
word32 p, q = 6+52/n;
word32 sum = q * DELTA;
while (sum != 0)
{
e = sum>>2 & 3;
for (p = n-1; p > 0; p--)
{
z = v[p-1];
y = v[p] -= MX;
}
z = v[n-1];
y = v[0] -= MX;
sum -= DELTA;
}
ConditionalByteReverse(BIG_ENDIAN_ORDER, v, v, m_blockSize);
}
NAMESPACE_END
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