tea.cpp
// 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;
void TEA::Base::UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params)
{
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;
Block::Get(inBlock)(y)(z);
word32 sum = 0;
while (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;
Block::Get(inBlock)(y)(z);
word32 sum = m_limit;
while (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 &params)
{
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;
Block::Get(inBlock)(y)(z);
#ifdef __SUNPRO_CC
// workaround needed on Sun Studio 12u1 Sun C++ 5.10 SunOS_i386 128229-02 2009/09/21
size_t sum = 0;
while ((sum&0xffffffff) != m_limit)
#else
word32 sum = 0;
while (sum != m_limit)
#endif
{
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;
Block::Get(inBlock)(y)(z);
#ifdef __SUNPRO_CC
// workaround needed on Sun Studio 12u1 Sun C++ 5.10 SunOS_i386 128229-02 2009/09/21
size_t sum = m_limit;
while ((sum&0xffffffff) != 0)
#else
word32 sum = m_limit;
while (sum != 0)
#endif
{
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);
assert(IsAlignedOn(inBlock,GetAlignmentOf<word32>()));
assert(IsAlignedOn(outBlock,GetAlignmentOf<word32>()));
unsigned int n = m_blockSize / 4;
word32 *v = (word32*)(void *)outBlock;
ConditionalByteReverse(BIG_ENDIAN_ORDER, v, (const word32*)(void *)inBlock, m_blockSize);
word32 y = v[0], 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);
assert(IsAlignedOn(inBlock,GetAlignmentOf<word32>()));
assert(IsAlignedOn(outBlock,GetAlignmentOf<word32>()));
unsigned int n = m_blockSize / 4;
word32 *v = (word32*)(void *)outBlock;
ConditionalByteReverse(BIG_ENDIAN_ORDER, v, (const word32*)(void *)inBlock, m_blockSize);
word32 y = v[0], z = v[n-1], 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
IsAlignedOn
bool IsAlignedOn(const void *ptr, unsigned int alignment)
Determines whether ptr is aligned to a minimum value.
Definition: misc.h:907
BIG_ENDIAN_ORDER
@ BIG_ENDIAN_ORDER
byte order is big-endian
Definition: cryptlib.h:127
tea.h
Classes for the TEA, BTEA and XTEA block ciphers.
misc.h
Utility functions for the Crypto++ library.
PutBlock
Access a block of memory.
Definition: misc.h:2208
BlockGetAndPut
Access a block of memory.
Definition: misc.h:2246
ConditionalByteReverse
T ConditionalByteReverse(ByteOrder order, T value)
Reverses bytes in a value depending upon endianess.
Definition: misc.h:1849
CryptoPP
Crypto++ library namespace.
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:277