add XTEA and BTEA

1 files changed, 107 insertions, 14 deletions

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<word32, BigEndian> 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<word32, BigEndian> 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<ROUNDS; i++)
+	while (sum != m_limit)
 	{   
 		sum += DELTA;
-		y += (z << 4) + k[0] ^ z + sum ^ (z >> 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<word32, BigEndian> 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<ROUNDS; i++)
+	word32 sum = m_limit;
+	while (sum != 0)
 	{
-		z -= (y << 4) + k[2] ^ y + sum ^ (y >> 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