Crypto++: cast.cpp Source File

00001 // cast.cpp - written and placed in the public domain by Wei Dai and Leonard Janke
00002 // based on Steve Reid's public domain cast.c
00003 
00004 #include "pch.h"
00005 #include "cast.h"
00006 #include "misc.h"
00007 
00008 NAMESPACE_BEGIN(CryptoPP)
00009 
00010 /* Macros to access 8-bit bytes out of a 32-bit word */
00011 #define U8a(x) GETBYTE(x,3)
00012 #define U8b(x) GETBYTE(x,2)
00013 #define U8c(x) GETBYTE(x,1)
00014 #define U8d(x) GETBYTE(x,0)
00015 
00016 /* CAST uses three different round functions */
00017 #define f1(l, r, km, kr) \
00018         t = rotlVariable(km + r, kr); \
00019         l ^= ((S[0][U8a(t)] ^ S[1][U8b(t)]) - \
00020          S[2][U8c(t)]) + S[3][U8d(t)];
00021 #define f2(l, r, km, kr) \
00022         t = rotlVariable(km ^ r, kr); \
00023         l ^= ((S[0][U8a(t)] - S[1][U8b(t)]) + \
00024          S[2][U8c(t)]) ^ S[3][U8d(t)];
00025 #define f3(l, r, km, kr) \
00026         t = rotlVariable(km - r, kr); \
00027         l ^= ((S[0][U8a(t)] + S[1][U8b(t)]) ^ \
00028          S[2][U8c(t)]) - S[3][U8d(t)];
00029 
00030 #define F1(l, r, i, j) f1(l, r, K[i], K[i+j])
00031 #define F2(l, r, i, j) f2(l, r, K[i], K[i+j])
00032 #define F3(l, r, i, j) f3(l, r, K[i], K[i+j])
00033 
00034 typedef BlockGetAndPut<word32, BigEndian> Block;
00035 
00036 void CAST128::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
00037 {
00038         word32 t, l, r;
00039 
00040         /* Get inblock into l,r */
00041         Block::Get(inBlock)(l)(r);
00042         /* Do the work */
00043         F1(l, r,  0, 16);
00044         F2(r, l,  1, 16);
00045         F3(l, r,  2, 16);
00046         F1(r, l,  3, 16);
00047         F2(l, r,  4, 16);
00048         F3(r, l,  5, 16);
00049         F1(l, r,  6, 16);
00050         F2(r, l,  7, 16);
00051         F3(l, r,  8, 16);
00052         F1(r, l,  9, 16);
00053         F2(l, r, 10, 16);
00054         F3(r, l, 11, 16);
00055         /* Only do full 16 rounds if key length > 80 bits */
00056         if (!reduced) {
00057                 F1(l, r, 12, 16);
00058                 F2(r, l, 13, 16);
00059                 F3(l, r, 14, 16);
00060                 F1(r, l, 15, 16);
00061         }
00062         /* Put l,r into outblock */
00063         Block::Put(xorBlock, outBlock)(r)(l);
00064 }
00065 
00066 void CAST128::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
00067 {
00068         word32 t, l, r;
00069 
00070         /* Get inblock into l,r */
00071         Block::Get(inBlock)(r)(l);
00072         /* Only do full 16 rounds if key length > 80 bits */
00073         if (!reduced) {
00074                 F1(r, l, 15, 16);
00075                 F3(l, r, 14, 16);
00076                 F2(r, l, 13, 16);
00077                 F1(l, r, 12, 16);
00078         }
00079         F3(r, l, 11, 16);
00080         F2(l, r, 10, 16);
00081         F1(r, l,  9, 16);
00082         F3(l, r,  8, 16);
00083         F2(r, l,  7, 16);
00084         F1(l, r,  6, 16);
00085         F3(r, l,  5, 16);
00086         F2(l, r,  4, 16);
00087         F1(r, l,  3, 16);
00088         F3(l, r,  2, 16);
00089         F2(r, l,  1, 16);
00090         F1(l, r,  0, 16);
00091         /* Put l,r into outblock */
00092         Block::Put(xorBlock, outBlock)(l)(r);
00093         /* Wipe clean */
00094         t = l = r = 0;
00095 }
00096 
00097 void CAST128::Base::UncheckedSetKey(const byte *userKey, unsigned int keylength, const NameValuePairs &)
00098 {
00099         AssertValidKeyLength(keylength);
00100 
00101         reduced = (keylength <= 10);
00102 
00103         word32 X[4], Z[4];
00104         GetUserKey(BIG_ENDIAN_ORDER, X, 4, userKey, keylength);
00105 
00106 #define x(i) GETBYTE(X[i/4], 3-i%4)
00107 #define z(i) GETBYTE(Z[i/4], 3-i%4)
00108 
00109         unsigned int i;
00110         for (i=0; i<=16; i+=16)
00111         {
00112                 // this part is copied directly from RFC 2144 (with some search and replace) by Wei Dai
00113                 Z[0] = X[0] ^ S[4][x(0xD)] ^ S[5][x(0xF)] ^ S[6][x(0xC)] ^ S[7][x(0xE)] ^ S[6][x(0x8)];
00114                 Z[1] = X[2] ^ S[4][z(0x0)] ^ S[5][z(0x2)] ^ S[6][z(0x1)] ^ S[7][z(0x3)] ^ S[7][x(0xA)];
00115                 Z[2] = X[3] ^ S[4][z(0x7)] ^ S[5][z(0x6)] ^ S[6][z(0x5)] ^ S[7][z(0x4)] ^ S[4][x(0x9)];
00116                 Z[3] = X[1] ^ S[4][z(0xA)] ^ S[5][z(0x9)] ^ S[6][z(0xB)] ^ S[7][z(0x8)] ^ S[5][x(0xB)];
00117                 K[i+0] = S[4][z(0x8)] ^ S[5][z(0x9)] ^ S[6][z(0x7)] ^ S[7][z(0x6)] ^ S[4][z(0x2)];
00118                 K[i+1] = S[4][z(0xA)] ^ S[5][z(0xB)] ^ S[6][z(0x5)] ^ S[7][z(0x4)] ^ S[5][z(0x6)];
00119                 K[i+2] = S[4][z(0xC)] ^ S[5][z(0xD)] ^ S[6][z(0x3)] ^ S[7][z(0x2)] ^ S[6][z(0x9)];
00120                 K[i+3] = S[4][z(0xE)] ^ S[5][z(0xF)] ^ S[6][z(0x1)] ^ S[7][z(0x0)] ^ S[7][z(0xC)];
00121                 X[0] = Z[2] ^ S[4][z(0x5)] ^ S[5][z(0x7)] ^ S[6][z(0x4)] ^ S[7][z(0x6)] ^ S[6][z(0x0)];
00122                 X[1] = Z[0] ^ S[4][x(0x0)] ^ S[5][x(0x2)] ^ S[6][x(0x1)] ^ S[7][x(0x3)] ^ S[7][z(0x2)];
00123                 X[2] = Z[1] ^ S[4][x(0x7)] ^ S[5][x(0x6)] ^ S[6][x(0x5)] ^ S[7][x(0x4)] ^ S[4][z(0x1)];
00124                 X[3] = Z[3] ^ S[4][x(0xA)] ^ S[5][x(0x9)] ^ S[6][x(0xB)] ^ S[7][x(0x8)] ^ S[5][z(0x3)];
00125                 K[i+4] = S[4][x(0x3)] ^ S[5][x(0x2)] ^ S[6][x(0xC)] ^ S[7][x(0xD)] ^ S[4][x(0x8)];
00126                 K[i+5] = S[4][x(0x1)] ^ S[5][x(0x0)] ^ S[6][x(0xE)] ^ S[7][x(0xF)] ^ S[5][x(0xD)];
00127                 K[i+6] = S[4][x(0x7)] ^ S[5][x(0x6)] ^ S[6][x(0x8)] ^ S[7][x(0x9)] ^ S[6][x(0x3)];
00128                 K[i+7] = S[4][x(0x5)] ^ S[5][x(0x4)] ^ S[6][x(0xA)] ^ S[7][x(0xB)] ^ S[7][x(0x7)];
00129                 Z[0] = X[0] ^ S[4][x(0xD)] ^ S[5][x(0xF)] ^ S[6][x(0xC)] ^ S[7][x(0xE)] ^ S[6][x(0x8)];
00130                 Z[1] = X[2] ^ S[4][z(0x0)] ^ S[5][z(0x2)] ^ S[6][z(0x1)] ^ S[7][z(0x3)] ^ S[7][x(0xA)];
00131                 Z[2] = X[3] ^ S[4][z(0x7)] ^ S[5][z(0x6)] ^ S[6][z(0x5)] ^ S[7][z(0x4)] ^ S[4][x(0x9)];
00132                 Z[3] = X[1] ^ S[4][z(0xA)] ^ S[5][z(0x9)] ^ S[6][z(0xB)] ^ S[7][z(0x8)] ^ S[5][x(0xB)];
00133                 K[i+8] = S[4][z(0x3)] ^ S[5][z(0x2)] ^ S[6][z(0xC)] ^ S[7][z(0xD)] ^ S[4][z(0x9)];
00134                 K[i+9] = S[4][z(0x1)] ^ S[5][z(0x0)] ^ S[6][z(0xE)] ^ S[7][z(0xF)] ^ S[5][z(0xC)];
00135                 K[i+10] = S[4][z(0x7)] ^ S[5][z(0x6)] ^ S[6][z(0x8)] ^ S[7][z(0x9)] ^ S[6][z(0x2)];
00136                 K[i+11] = S[4][z(0x5)] ^ S[5][z(0x4)] ^ S[6][z(0xA)] ^ S[7][z(0xB)] ^ S[7][z(0x6)];
00137                 X[0] = Z[2] ^ S[4][z(0x5)] ^ S[5][z(0x7)] ^ S[6][z(0x4)] ^ S[7][z(0x6)] ^ S[6][z(0x0)];
00138                 X[1] = Z[0] ^ S[4][x(0x0)] ^ S[5][x(0x2)] ^ S[6][x(0x1)] ^ S[7][x(0x3)] ^ S[7][z(0x2)];
00139                 X[2] = Z[1] ^ S[4][x(0x7)] ^ S[5][x(0x6)] ^ S[6][x(0x5)] ^ S[7][x(0x4)] ^ S[4][z(0x1)];
00140                 X[3] = Z[3] ^ S[4][x(0xA)] ^ S[5][x(0x9)] ^ S[6][x(0xB)] ^ S[7][x(0x8)] ^ S[5][z(0x3)];
00141                 K[i+12] = S[4][x(0x8)] ^ S[5][x(0x9)] ^ S[6][x(0x7)] ^ S[7][x(0x6)] ^ S[4][x(0x3)];
00142                 K[i+13] = S[4][x(0xA)] ^ S[5][x(0xB)] ^ S[6][x(0x5)] ^ S[7][x(0x4)] ^ S[5][x(0x7)];
00143                 K[i+14] = S[4][x(0xC)] ^ S[5][x(0xD)] ^ S[6][x(0x3)] ^ S[7][x(0x2)] ^ S[6][x(0x8)];
00144                 K[i+15] = S[4][x(0xE)] ^ S[5][x(0xF)] ^ S[6][x(0x1)] ^ S[7][x(0x0)] ^ S[7][x(0xD)];
00145         }
00146 
00147         for (i=16; i<32; i++)
00148                 K[i] &= 0x1f;
00149 }
00150 
00151 // The following CAST-256 implementation was contributed by Leonard Janke
00152 
00153 const word32 CAST256::Base::t_m[8][24]={
00154 {       0x5a827999, 0xd151d6a1, 0x482133a9, 0xbef090b1, 0x35bfedb9, 0xac8f4ac1, 
00155         0x235ea7c9, 0x9a2e04d1, 0x10fd61d9, 0x87ccbee1, 0xfe9c1be9, 0x756b78f1, 
00156         0xec3ad5f9, 0x630a3301, 0xd9d99009, 0x50a8ed11, 0xc7784a19, 0x3e47a721, 
00157         0xb5170429, 0x2be66131, 0xa2b5be39, 0x19851b41, 0x90547849, 0x0723d551}, 
00158 {       0xc95c653a, 0x402bc242, 0xb6fb1f4a, 0x2dca7c52, 0xa499d95a, 0x1b693662, 
00159         0x9238936a, 0x0907f072, 0x7fd74d7a, 0xf6a6aa82, 0x6d76078a, 0xe4456492, 
00160         0x5b14c19a, 0xd1e41ea2, 0x48b37baa, 0xbf82d8b2, 0x365235ba, 0xad2192c2, 
00161         0x23f0efca, 0x9ac04cd2, 0x118fa9da, 0x885f06e2, 0xff2e63ea, 0x75fdc0f2}, 
00162 {       0x383650db, 0xaf05ade3, 0x25d50aeb, 0x9ca467f3, 0x1373c4fb, 0x8a432203, 
00163         0x01127f0b, 0x77e1dc13, 0xeeb1391b, 0x65809623, 0xdc4ff32b, 0x531f5033, 
00164         0xc9eead3b, 0x40be0a43, 0xb78d674b, 0x2e5cc453, 0xa52c215b, 0x1bfb7e63, 
00165         0x92cadb6b, 0x099a3873, 0x8069957b, 0xf738f283, 0x6e084f8b, 0xe4d7ac93}, 
00166 {       0xa7103c7c, 0x1ddf9984, 0x94aef68c, 0x0b7e5394, 0x824db09c, 0xf91d0da4, 
00167         0x6fec6aac, 0xe6bbc7b4, 0x5d8b24bc, 0xd45a81c4, 0x4b29decc, 0xc1f93bd4, 
00168         0x38c898dc, 0xaf97f5e4, 0x266752ec, 0x9d36aff4, 0x14060cfc, 0x8ad56a04, 
00169         0x01a4c70c, 0x78742414, 0xef43811c, 0x6612de24, 0xdce23b2c, 0x53b19834}, 
00170 {       0x15ea281d, 0x8cb98525, 0x0388e22d, 0x7a583f35, 0xf1279c3d, 0x67f6f945, 
00171         0xdec6564d, 0x5595b355, 0xcc65105d, 0x43346d65, 0xba03ca6d, 0x30d32775, 
00172         0xa7a2847d, 0x1e71e185, 0x95413e8d, 0x0c109b95, 0x82dff89d, 0xf9af55a5, 
00173         0x707eb2ad, 0xe74e0fb5, 0x5e1d6cbd, 0xd4ecc9c5, 0x4bbc26cd, 0xc28b83d5}, 
00174 {       0x84c413be, 0xfb9370c6, 0x7262cdce, 0xe9322ad6, 0x600187de, 0xd6d0e4e6, 
00175         0x4da041ee, 0xc46f9ef6, 0x3b3efbfe, 0xb20e5906, 0x28ddb60e, 0x9fad1316, 
00176         0x167c701e, 0x8d4bcd26, 0x041b2a2e, 0x7aea8736, 0xf1b9e43e, 0x68894146, 
00177         0xdf589e4e, 0x5627fb56, 0xccf7585e, 0x43c6b566, 0xba96126e, 0x31656f76}, 
00178 {       0xf39dff5f, 0x6a6d5c67, 0xe13cb96f, 0x580c1677, 0xcedb737f, 0x45aad087, 
00179         0xbc7a2d8f, 0x33498a97, 0xaa18e79f, 0x20e844a7, 0x97b7a1af, 0x0e86feb7, 
00180         0x85565bbf, 0xfc25b8c7, 0x72f515cf, 0xe9c472d7, 0x6093cfdf, 0xd7632ce7, 
00181         0x4e3289ef, 0xc501e6f7, 0x3bd143ff, 0xb2a0a107, 0x296ffe0f, 0xa03f5b17}, 
00182 {       0x6277eb00, 0xd9474808, 0x5016a510, 0xc6e60218, 0x3db55f20, 0xb484bc28, 
00183         0x2b541930, 0xa2237638, 0x18f2d340, 0x8fc23048, 0x06918d50, 0x7d60ea58, 
00184         0xf4304760, 0x6affa468, 0xe1cf0170, 0x589e5e78, 0xcf6dbb80, 0x463d1888, 
00185         0xbd0c7590, 0x33dbd298, 0xaaab2fa0, 0x217a8ca8, 0x9849e9b0, 0x0f1946b8} 
00186 };
00187 
00188 const unsigned int CAST256::Base::t_r[8][24]={ 
00189         {19, 27, 3, 11, 19, 27, 3, 11, 19, 27, 3, 11, 19, 27, 3, 11, 19, 27, 3, 11, 19, 27, 3, 11}, 
00190         {4, 12, 20, 28, 4, 12, 20, 28, 4, 12, 20, 28, 4, 12, 20, 28, 4, 12, 20, 28, 4, 12, 20, 28}, 
00191         {21, 29, 5, 13, 21, 29, 5, 13, 21, 29, 5, 13, 21, 29, 5, 13, 21, 29, 5, 13, 21, 29, 5, 13}, 
00192         {6, 14, 22, 30, 6, 14, 22, 30, 6, 14, 22, 30, 6, 14, 22, 30, 6, 14, 22, 30, 6, 14, 22, 30}, 
00193         {23, 31, 7, 15, 23, 31, 7, 15, 23, 31, 7, 15, 23, 31, 7, 15, 23, 31, 7, 15, 23, 31, 7, 15}, 
00194         {8, 16, 24, 0, 8, 16, 24, 0, 8, 16, 24, 0, 8, 16, 24, 0, 8, 16, 24, 0, 8, 16, 24, 0}, 
00195         {25, 1, 9, 17, 25, 1, 9, 17, 25, 1, 9, 17, 25, 1, 9, 17, 25, 1, 9, 17, 25, 1, 9, 17}, 
00196         {10, 18, 26, 2, 10, 18, 26, 2, 10, 18, 26, 2, 10, 18, 26, 2, 10, 18, 26, 2, 10, 18, 26, 2}
00197 };
00198 
00199 #define Q(i) \
00200         F1(block[2],block[3],8*i+4,-4); \
00201         F2(block[1],block[2],8*i+5,-4); \
00202         F3(block[0],block[1],8*i+6,-4); \
00203         F1(block[3],block[0],8*i+7,-4);
00204 
00205 #define QBar(i) \
00206         F1(block[3],block[0],8*i+7,-4); \
00207         F3(block[0],block[1],8*i+6,-4); \
00208         F2(block[1],block[2],8*i+5,-4); \
00209         F1(block[2],block[3],8*i+4,-4);
00210 
00211 /* CAST256's encrypt/decrypt functions  are identical except for the order that
00212 the keys are used */
00213 
00214 void CAST256::Base::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
00215 {
00216         word32 t, block[4];
00217         Block::Get(inBlock)(block[0])(block[1])(block[2])(block[3]);
00218 
00219         // Perform 6 forward quad rounds
00220         Q(0);
00221         Q(1);
00222         Q(2);
00223         Q(3);
00224         Q(4);
00225         Q(5);
00226 
00227         // Perform 6 reverse quad rounds
00228         QBar(6);
00229         QBar(7);
00230         QBar(8);
00231         QBar(9);
00232         QBar(10);
00233         QBar(11);
00234 
00235         Block::Put(xorBlock, outBlock)(block[0])(block[1])(block[2])(block[3]);
00236 }
00237 
00238 /* Set up a CAST-256 key */
00239 
00240 void CAST256::Base::Omega(int i, word32 kappa[8])
00241 {
00242         word32 t;
00243 
00244         f1(kappa[6],kappa[7],t_m[0][i],t_r[0][i]);
00245         f2(kappa[5],kappa[6],t_m[1][i],t_r[1][i]);
00246         f3(kappa[4],kappa[5],t_m[2][i],t_r[2][i]);
00247         f1(kappa[3],kappa[4],t_m[3][i],t_r[3][i]);
00248         f2(kappa[2],kappa[3],t_m[4][i],t_r[4][i]);
00249         f3(kappa[1],kappa[2],t_m[5][i],t_r[5][i]);
00250         f1(kappa[0],kappa[1],t_m[6][i],t_r[6][i]);
00251         f2(kappa[7],kappa[0],t_m[7][i],t_r[7][i]);
00252 }
00253 
00254 void CAST256::Base::UncheckedSetKey(const byte *userKey, unsigned int keylength, const NameValuePairs &)
00255 {
00256         AssertValidKeyLength(keylength);
00257 
00258         word32 kappa[8];
00259         GetUserKey(BIG_ENDIAN_ORDER, kappa, 8, userKey, keylength);
00260 
00261         for(int i=0; i<12; ++i)
00262         {
00263                 Omega(2*i,kappa);
00264                 Omega(2*i+1,kappa);
00265                 
00266                 K[8*i]=kappa[0] & 31;
00267                 K[8*i+1]=kappa[2] & 31;
00268                 K[8*i+2]=kappa[4] & 31;
00269                 K[8*i+3]=kappa[6] & 31;
00270                 K[8*i+4]=kappa[7];
00271                 K[8*i+5]=kappa[5];
00272                 K[8*i+6]=kappa[3];
00273                 K[8*i+7]=kappa[1];
00274         }
00275 
00276         if (!IsForwardTransformation())
00277         {
00278                 for(int j=0; j<6; ++j)
00279                 {
00280                         for(int i=0; i<4; ++i)
00281                         {
00282                                 int i1=8*j+i;
00283                                 int i2=8*(11-j)+i;
00284 
00285                                 assert(i1<i2);
00286 
00287                                 std::swap(K[i1],K[i2]); 
00288                                 std::swap(K[i1+4],K[i2+4]); 
00289                         }
00290                 }
00291         }
00292 
00293         memset(kappa, 0, sizeof(kappa));
00294 }
00295 
00296 NAMESPACE_END