2.9BSD - /usr/src/lib/c/gen/crypt.c

   1: /*	@(#)crypt.c	2.1	SCCS id keyword	*/
   2: /*
   3:  * This program implements the
   4:  * Proposed Federal Information Processing
   5:  *  Data Encryption Standard.
   6:  * See Federal Register, March 17, 1975 (40FR12134)
   7:  */
   8: 
   9: /*
  10:  * Initial permutation,
  11:  */
  12: static  char    IP[] = {
  13:     58,50,42,34,26,18,10, 2,
  14:     60,52,44,36,28,20,12, 4,
  15:     62,54,46,38,30,22,14, 6,
  16:     64,56,48,40,32,24,16, 8,
  17:     57,49,41,33,25,17, 9, 1,
  18:     59,51,43,35,27,19,11, 3,
  19:     61,53,45,37,29,21,13, 5,
  20:     63,55,47,39,31,23,15, 7,
  21: };
  22: 
  23: /*
  24:  * Final permutation, FP = IP^(-1)
  25:  */
  26: static  char    FP[] = {
  27:     40, 8,48,16,56,24,64,32,
  28:     39, 7,47,15,55,23,63,31,
  29:     38, 6,46,14,54,22,62,30,
  30:     37, 5,45,13,53,21,61,29,
  31:     36, 4,44,12,52,20,60,28,
  32:     35, 3,43,11,51,19,59,27,
  33:     34, 2,42,10,50,18,58,26,
  34:     33, 1,41, 9,49,17,57,25,
  35: };
  36: 
  37: /*
  38:  * Permuted-choice 1 from the key bits
  39:  * to yield C and D.
  40:  * Note that bits 8,16... are left out:
  41:  * They are intended for a parity check.
  42:  */
  43: static  char    PC1_C[] = {
  44:     57,49,41,33,25,17, 9,
  45:      1,58,50,42,34,26,18,
  46:     10, 2,59,51,43,35,27,
  47:     19,11, 3,60,52,44,36,
  48: };
  49: 
  50: static  char    PC1_D[] {
  51:     63,55,47,39,31,23,15,
  52:      7,62,54,46,38,30,22,
  53:     14, 6,61,53,45,37,29,
  54:     21,13, 5,28,20,12, 4,
  55: };
  56: 
  57: /*
  58:  * Sequence of shifts used for the key schedule.
  59: */
  60: static  char    shifts[] = {
  61:     1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1,
  62: };
  63: 
  64: /*
  65:  * Permuted-choice 2, to pick out the bits from
  66:  * the CD array that generate the key schedule.
  67:  */
  68: static  char    PC2_C[] = {
  69:     14,17,11,24, 1, 5,
  70:      3,28,15, 6,21,10,
  71:     23,19,12, 4,26, 8,
  72:     16, 7,27,20,13, 2,
  73: };
  74: 
  75: static  char    PC2_D[] = {
  76:     41,52,31,37,47,55,
  77:     30,40,51,45,33,48,
  78:     44,49,39,56,34,53,
  79:     46,42,50,36,29,32,
  80: };
  81: 
  82: /*
  83:  * The C and D arrays used to calculate the key schedule.
  84:  */
  85: 
  86: static  char    C[28];
  87: static  char    D[28];
  88: /*
  89:  * The key schedule.
  90:  * Generated from the key.
  91:  */
  92: static  char    KS[16][48];
  93: 
  94: /*
  95:  * Set up the key schedule from the key.
  96:  */
  97: 
  98: setkey(key)
  99: char *key;
 100: {
 101:     register i, j, k;
 102:     int t;
 103: 
 104:     /*
 105: 	 * First, generate C and D by permuting
 106: 	 * the key.  The low order bit of each
 107: 	 * 8-bit char is not used, so C and D are only 28
 108: 	 * bits apiece.
 109: 	 */
 110:     for (i=0; i<28; i++) {
 111:         C[i] = key[PC1_C[i]-1];
 112:         D[i] = key[PC1_D[i]-1];
 113:     }
 114:     /*
 115: 	 * To generate Ki, rotate C and D according
 116: 	 * to schedule and pick up a permutation
 117: 	 * using PC2.
 118: 	 */
 119:     for (i=0; i<16; i++) {
 120:         /*
 121: 		 * rotate.
 122: 		 */
 123:         for (k=0; k<shifts[i]; k++) {
 124:             t = C[0];
 125:             for (j=0; j<28-1; j++)
 126:                 C[j] = C[j+1];
 127:             C[27] = t;
 128:             t = D[0];
 129:             for (j=0; j<28-1; j++)
 130:                 D[j] = D[j+1];
 131:             D[27] = t;
 132:         }
 133:         /*
 134: 		 * get Ki. Note C and D are concatenated.
 135: 		 */
 136:         for (j=0; j<24; j++) {
 137:             KS[i][j] = C[PC2_C[j]-1];
 138:             KS[i][j+24] = D[PC2_D[j]-28-1];
 139:         }
 140:     }
 141: }
 142: 
 143: /*
 144:  * The E bit-selection table.
 145:  */
 146: static  char    E[48];
 147: static  char    e[] {
 148:     32, 1, 2, 3, 4, 5,
 149:      4, 5, 6, 7, 8, 9,
 150:      8, 9,10,11,12,13,
 151:     12,13,14,15,16,17,
 152:     16,17,18,19,20,21,
 153:     20,21,22,23,24,25,
 154:     24,25,26,27,28,29,
 155:     28,29,30,31,32, 1,
 156: };
 157: 
 158: /*
 159:  * The 8 selection functions.
 160:  * For some reason, they give a 0-origin
 161:  * index, unlike everything else.
 162:  */
 163: static  char    S[8][64] {
 164:     14, 4,13, 1, 2,15,11, 8, 3,10, 6,12, 5, 9, 0, 7,
 165:      0,15, 7, 4,14, 2,13, 1,10, 6,12,11, 9, 5, 3, 8,
 166:      4, 1,14, 8,13, 6, 2,11,15,12, 9, 7, 3,10, 5, 0,
 167:     15,12, 8, 2, 4, 9, 1, 7, 5,11, 3,14,10, 0, 6,13,
 168: 
 169:     15, 1, 8,14, 6,11, 3, 4, 9, 7, 2,13,12, 0, 5,10,
 170:      3,13, 4, 7,15, 2, 8,14,12, 0, 1,10, 6, 9,11, 5,
 171:      0,14, 7,11,10, 4,13, 1, 5, 8,12, 6, 9, 3, 2,15,
 172:     13, 8,10, 1, 3,15, 4, 2,11, 6, 7,12, 0, 5,14, 9,
 173: 
 174:     10, 0, 9,14, 6, 3,15, 5, 1,13,12, 7,11, 4, 2, 8,
 175:     13, 7, 0, 9, 3, 4, 6,10, 2, 8, 5,14,12,11,15, 1,
 176:     13, 6, 4, 9, 8,15, 3, 0,11, 1, 2,12, 5,10,14, 7,
 177:      1,10,13, 0, 6, 9, 8, 7, 4,15,14, 3,11, 5, 2,12,
 178: 
 179:      7,13,14, 3, 0, 6, 9,10, 1, 2, 8, 5,11,12, 4,15,
 180:     13, 8,11, 5, 6,15, 0, 3, 4, 7, 2,12, 1,10,14, 9,
 181:     10, 6, 9, 0,12,11, 7,13,15, 1, 3,14, 5, 2, 8, 4,
 182:      3,15, 0, 6,10, 1,13, 8, 9, 4, 5,11,12, 7, 2,14,
 183: 
 184:      2,12, 4, 1, 7,10,11, 6, 8, 5, 3,15,13, 0,14, 9,
 185:     14,11, 2,12, 4, 7,13, 1, 5, 0,15,10, 3, 9, 8, 6,
 186:      4, 2, 1,11,10,13, 7, 8,15, 9,12, 5, 6, 3, 0,14,
 187:     11, 8,12, 7, 1,14, 2,13, 6,15, 0, 9,10, 4, 5, 3,
 188: 
 189:     12, 1,10,15, 9, 2, 6, 8, 0,13, 3, 4,14, 7, 5,11,
 190:     10,15, 4, 2, 7,12, 9, 5, 6, 1,13,14, 0,11, 3, 8,
 191:      9,14,15, 5, 2, 8,12, 3, 7, 0, 4,10, 1,13,11, 6,
 192:      4, 3, 2,12, 9, 5,15,10,11,14, 1, 7, 6, 0, 8,13,
 193: 
 194:      4,11, 2,14,15, 0, 8,13, 3,12, 9, 7, 5,10, 6, 1,
 195:     13, 0,11, 7, 4, 9, 1,10,14, 3, 5,12, 2,15, 8, 6,
 196:      1, 4,11,13,12, 3, 7,14,10,15, 6, 8, 0, 5, 9, 2,
 197:      6,11,13, 8, 1, 4,10, 7, 9, 5, 0,15,14, 2, 3,12,
 198: 
 199:     13, 2, 8, 4, 6,15,11, 1,10, 9, 3,14, 5, 0,12, 7,
 200:      1,15,13, 8,10, 3, 7, 4,12, 5, 6,11, 0,14, 9, 2,
 201:      7,11, 4, 1, 9,12,14, 2, 0, 6,10,13,15, 3, 5, 8,
 202:      2, 1,14, 7, 4,10, 8,13,15,12, 9, 0, 3, 5, 6,11,
 203: };
 204: 
 205: /*
 206:  * P is a permutation on the selected combination
 207:  * of the current L and key.
 208:  */
 209: static  char    P[] {
 210:     16, 7,20,21,
 211:     29,12,28,17,
 212:      1,15,23,26,
 213:      5,18,31,10,
 214:      2, 8,24,14,
 215:     32,27, 3, 9,
 216:     19,13,30, 6,
 217:     22,11, 4,25,
 218: };
 219: 
 220: /*
 221:  * The current block, divided into 2 halves.
 222:  */
 223: static  char    L[32], R[32];
 224: static  char    tempL[32];
 225: static  char    f[32];
 226: 
 227: /*
 228:  * The combination of the key and the input, before selection.
 229:  */
 230: static  char    preS[48];
 231: 
 232: /*
 233:  * The payoff: encrypt a block.
 234:  */
 235: 
 236: encrypt(block, edflag)
 237: char *block;
 238: {
 239:     int i, ii;
 240:     register t, j, k;
 241: 
 242:     /*
 243: 	 * First, permute the bits in the input
 244: 	 */
 245:     for (j=0; j<64; j++)
 246:         L[j] = block[IP[j]-1];
 247:     /*
 248: 	 * Perform an encryption operation 16 times.
 249: 	 */
 250:     for (ii=0; ii<16; ii++) {
 251:         /*
 252: 		 * Set direction
 253: 		 */
 254:         if (edflag)
 255:             i = 15-ii;
 256:         else
 257:             i = ii;
 258:         /*
 259: 		 * Save the R array,
 260: 		 * which will be the new L.
 261: 		 */
 262:         for (j=0; j<32; j++)
 263:             tempL[j] = R[j];
 264:         /*
 265: 		 * Expand R to 48 bits using the E selector;
 266: 		 * exclusive-or with the current key bits.
 267: 		 */
 268:         for (j=0; j<48; j++)
 269:             preS[j] = R[E[j]-1] ^ KS[i][j];
 270:         /*
 271: 		 * The pre-select bits are now considered
 272: 		 * in 8 groups of 6 bits each.
 273: 		 * The 8 selection functions map these
 274: 		 * 6-bit quantities into 4-bit quantities
 275: 		 * and the results permuted
 276: 		 * to make an f(R, K).
 277: 		 * The indexing into the selection functions
 278: 		 * is peculiar; it could be simplified by
 279: 		 * rewriting the tables.
 280: 		 */
 281:         for (j=0; j<8; j++) {
 282:             t = 6*j;
 283:             k = S[j][(preS[t+0]<<5)+
 284:                 (preS[t+1]<<3)+
 285:                 (preS[t+2]<<2)+
 286:                 (preS[t+3]<<1)+
 287:                 (preS[t+4]<<0)+
 288:                 (preS[t+5]<<4)];
 289:             t = 4*j;
 290:             f[t+0] = (k>>3)&01;
 291:             f[t+1] = (k>>2)&01;
 292:             f[t+2] = (k>>1)&01;
 293:             f[t+3] = (k>>0)&01;
 294:         }
 295:         /*
 296: 		 * The new R is L ^ f(R, K).
 297: 		 * The f here has to be permuted first, though.
 298: 		 */
 299:         for (j=0; j<32; j++)
 300:             R[j] = L[j] ^ f[P[j]-1];
 301:         /*
 302: 		 * Finally, the new L (the original R)
 303: 		 * is copied back.
 304: 		 */
 305:         for (j=0; j<32; j++)
 306:             L[j] = tempL[j];
 307:     }
 308:     /*
 309: 	 * The output L and R are reversed.
 310: 	 */
 311:     for (j=0; j<32; j++) {
 312:         t = L[j];
 313:         L[j] = R[j];
 314:         R[j] = t;
 315:     }
 316:     /*
 317: 	 * The final output
 318: 	 * gets the inverse permutation of the very original.
 319: 	 */
 320:     for (j=0; j<64; j++)
 321:         block[j] = L[FP[j]-1];
 322: }
 323: 
 324: char *
 325: crypt(pw,salt)
 326: char *pw;
 327: char *salt;
 328: {
 329:     register i, j, c;
 330:     int temp;
 331:     static char block[66], iobuf[16];
 332:     for(i=0; i<66; i++)
 333:         block[i] = 0;
 334:     for(i=0; (c= *pw) && i<64; pw++){
 335:         for(j=0; j<7; j++, i++)
 336:             block[i] = (c>>(6-j)) & 01;
 337:         i++;
 338:     }
 339: 
 340:     setkey(block);
 341: 
 342:     for(i=0; i<66; i++)
 343:         block[i] = 0;
 344: 
 345:     for(i=0;i<48;i++)
 346:         E[i] = e[i];
 347: 
 348:     for(i=0;i<2;i++){
 349:         c = *salt++;
 350:         iobuf[i] = c;
 351:         if(c>'Z') c -= 6;
 352:         if(c>'9') c -= 7;
 353:         c -= '.';
 354:         for(j=0;j<6;j++){
 355:             if((c>>j) & 01){
 356:                 temp = E[6*i+j];
 357:                 E[6*i+j] = E[6*i+j+24];
 358:                 E[6*i+j+24] = temp;
 359:                 }
 360:             }
 361:         }
 362: 
 363:     for(i=0; i<25; i++)
 364:         encrypt(block,0);
 365: 
 366:     for(i=0; i<11; i++){
 367:         c = 0;
 368:         for(j=0; j<6; j++){
 369:             c <<= 1;
 370:             c |= block[6*i+j];
 371:             }
 372:         c += '.';
 373:         if(c>'9') c += 7;
 374:         if(c>'Z') c += 6;
 375:         iobuf[i+2] = c;
 376:     }
 377:     iobuf[i+2] = 0;
 378:     if(iobuf[1]==0)
 379:         iobuf[1] = iobuf[0];
 380:     return(iobuf);
 381: }

Defined functions

Defined variables