From 4bf1528bb04d54cb3008a8a6169a14de87f43bc8 Mon Sep 17 00:00:00 2001 From: weidai Date: Wed, 30 Jul 2003 00:28:54 +0000 Subject: add XTEA and BTEA --- tea.cpp | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 107 insertions(+), 14 deletions(-) (limited to 'tea.cpp') diff --git a/tea.cpp b/tea.cpp index 3b5d181c..a9710535 100644 --- a/tea.cpp +++ b/tea.cpp @@ -6,49 +6,142 @@ NAMESPACE_BEGIN(CryptoPP) -const word32 TEA::Base::DELTA = 0x9e3779b9; +static const word32 DELTA = 0x9e3779b9; +typedef BlockGetAndPut Block; -void TEA::Base::UncheckedSetKey(CipherDir direction, const byte *userKey, unsigned int length) +void TEA::Base::UncheckedSetKey(CipherDir direction, const byte *userKey, unsigned int length, unsigned int rounds) { AssertValidKeyLength(length); - GetUserKey(BIG_ENDIAN_ORDER, k.begin(), 4, userKey, KEYLENGTH); + GetUserKey(BIG_ENDIAN_ORDER, m_k.begin(), 4, userKey, KEYLENGTH); + m_limit = rounds * DELTA; } -typedef BlockGetAndPut Block; - void TEA::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const { word32 y, z; Block::Get(inBlock)(y)(z); word32 sum = 0; - for (int i=0; i> 5) + k[1]; - z += (y << 4) + k[2] ^ y + sum ^ (y >> 5) + k[3]; + 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); } -typedef BlockGetAndPut Block; - void TEA::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const { word32 y, z; Block::Get(inBlock)(y)(z); - word32 sum = DELTA << LOG_ROUNDS; - for (int i=0; i> 5) + k[3]; - y -= (z << 4) + k[0] ^ z + sum ^ (z >> 5) + k[1]; + 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(CipherDir direction, const byte *userKey, unsigned int length, unsigned int rounds) +{ + AssertValidKeyLength(length); + + GetUserKey(BIG_ENDIAN_ORDER, m_k.begin(), 4, userKey, KEYLENGTH); + m_limit = rounds * DELTA; +} + +void XTEA::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) + { + 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); + + word32 sum = m_limit; + while (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 +{ + unsigned int n = m_blockSize / 4; + word32 *v = (word32*)outBlock; + ConditionalByteReverse(BIG_ENDIAN_ORDER, v, (const word32*)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 +{ + unsigned int n = m_blockSize / 4; + word32 *v = (word32*)outBlock; + ConditionalByteReverse(BIG_ENDIAN_ORDER, v, (const word32*)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 -- cgit v1.2.1