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3way.cpp

00001 // 3way.cpp - modifed by Wei Dai from Joan Daemen's 3way.c
00002 // The original code and all modifications are in the public domain.
00003 
00004 #include "pch.h"
00005 #include "3way.h"
00006 #include "misc.h"
00007 
00008 NAMESPACE_BEGIN(CryptoPP)
00009 
00010 void ThreeWay_TestInstantiations()
00011 {
00012         ThreeWay::Encryption x1;
00013         ThreeWay::Decryption x2;
00014 }
00015 
00016 static const word32 START_E = 0x0b0b; // round constant of first encryption round
00017 static const word32 START_D = 0xb1b1; // round constant of first decryption round
00018 static const word32 RC_MODULUS = 0x11011;
00019 
00020 static inline word32 reverseBits(word32 a)
00021 {
00022         a = ((a & 0xAAAAAAAA) >> 1) | ((a & 0x55555555) << 1);
00023         a = ((a & 0xCCCCCCCC) >> 2) | ((a & 0x33333333) << 2);
00024         return ((a & 0xF0F0F0F0) >> 4) | ((a & 0x0F0F0F0F) << 4);
00025 }
00026 
00027 #define mu(a0, a1, a2)                          \
00028 {                                                                       \
00029         a1 = reverseBits(a1);                   \
00030         word32 t = reverseBits(a0);             \
00031         a0 = reverseBits(a2);                   \
00032         a2 = t;                                                 \
00033 }
00034 
00035 #define pi_gamma_pi(a0, a1, a2)         \
00036 {                                                                       \
00037         word32 b0, b2;                                  \
00038         b2 = rotlFixed(a2, 1U);                         \
00039         b0 = rotlFixed(a0, 22U);                                \
00040         a0 = rotlFixed(b0 ^ (a1|(~b2)), 1U);    \
00041         a2 = rotlFixed(b2 ^ (b0|(~a1)), 22U);\
00042         a1 ^= (b2|(~b0));                               \
00043 }
00044 
00045 // thanks to Paulo Barreto for this optimized theta()
00046 #define theta(a0, a1, a2)                                                                       \
00047 {                                                                                                                       \
00048         word32 b0, b1, c;                                                                               \
00049         c = a0 ^ a1 ^ a2;                                                                               \
00050         c = rotlFixed(c, 16U) ^ rotlFixed(c, 8U);                               \
00051         b0 = (a0 << 24) ^ (a2 >> 8) ^ (a1 << 8) ^ (a0 >> 24);   \
00052         b1 = (a1 << 24) ^ (a0 >> 8) ^ (a2 << 8) ^ (a1 >> 24);   \
00053         a0 ^= c ^ b0;                                                                                   \
00054         a1 ^= c ^ b1;                                                                                   \
00055         a2 ^= c ^ (b0 >> 16) ^ (b1 << 16);                                              \
00056 }                                                                                                                       
00057 
00058 #define rho(a0, a1, a2)                 \
00059 {                                                               \
00060         theta(a0, a1, a2);                      \
00061         pi_gamma_pi(a0, a1, a2);        \
00062 }                                                                                       
00063 
00064 void ThreeWay::Base::UncheckedSetKey(CipherDir dir, const byte *uk, unsigned int length, unsigned int r)
00065 {
00066         AssertValidKeyLength(length);
00067         AssertValidRounds(r);
00068 
00069         m_rounds = r;
00070 
00071         for (unsigned int i=0; i<3; i++)
00072                 m_k[i] = (word32)uk[4*i+3] | ((word32)uk[4*i+2]<<8) | ((word32)uk[4*i+1]<<16) | ((word32)uk[4*i]<<24);
00073 
00074         if (dir == DECRYPTION)
00075         {
00076                 theta(m_k[0], m_k[1], m_k[2]);
00077                 mu(m_k[0], m_k[1], m_k[2]);
00078                 m_k[0] = ByteReverse(m_k[0]);
00079                 m_k[1] = ByteReverse(m_k[1]);
00080                 m_k[2] = ByteReverse(m_k[2]);
00081         }
00082 }
00083 
00084 void ThreeWay::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
00085 {
00086         typedef BlockGetAndPut<word32, BigEndian> Block;
00087 
00088         word32 a0, a1, a2;
00089         Block::Get(inBlock)(a0)(a1)(a2);
00090 
00091         word32 rc = START_E;
00092 
00093         for(unsigned i=0; i<m_rounds; i++)
00094         {
00095                 a0 ^= m_k[0] ^ (rc<<16);
00096                 a1 ^= m_k[1];
00097                 a2 ^= m_k[2] ^ rc;
00098                 rho(a0, a1, a2);
00099 
00100                 rc <<= 1;
00101                 if (rc&0x10000) rc ^= 0x11011;
00102         }
00103         a0 ^= m_k[0] ^ (rc<<16);
00104         a1 ^= m_k[1];
00105         a2 ^= m_k[2] ^ rc;
00106         theta(a0, a1, a2);
00107 
00108         Block::Put(xorBlock, outBlock)(a0)(a1)(a2);
00109 }
00110 
00111 void ThreeWay::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
00112 {
00113         typedef BlockGetAndPut<word32, LittleEndian> Block;
00114 
00115         word32 a0, a1, a2;
00116         Block::Get(inBlock)(a0)(a1)(a2);
00117 
00118         word32 rc = START_D;
00119 
00120         mu(a0, a1, a2);
00121         for(unsigned i=0; i<m_rounds; i++)
00122         {
00123                 a0 ^= m_k[0] ^ (rc<<16);
00124                 a1 ^= m_k[1];
00125                 a2 ^= m_k[2] ^ rc;
00126                 rho(a0, a1, a2);
00127 
00128                 rc <<= 1;
00129                 if (rc&0x10000) rc ^= 0x11011;
00130         }
00131         a0 ^= m_k[0] ^ (rc<<16);
00132         a1 ^= m_k[1];
00133         a2 ^= m_k[2] ^ rc;
00134         theta(a0, a1, a2);
00135         mu(a0, a1, a2);
00136 
00137         Block::Put(xorBlock, outBlock)(a0)(a1)(a2);
00138 }
00139 
00140 NAMESPACE_END

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