usr/src/lib/libcrypt/common/des_encrypt.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma weak _des_encrypt1 = des_encrypt1
  31
  32 #include <sys/types.h>
  33
  34 void
  35 des_encrypt1(char *block, char *L, char *IP, char *R, char *preS, char *E,
  36         char KS[][48], char S[][64], char *f, char *tempL, char *P, char *FP)
  37 {
  38         int     i;
  39         int     t, j, k;
  40         char    t2;
  41
  42         /*
  43          * First, permute the bits in the input
  44          */
  45         for (j = 0; j < 64; j++)
  46                 L[j] = block[IP[j]-1];
  47         /*
  48          * Perform an encryption operation 16 times.
  49          */
  50         for (i = 0; i < 16; i++) {
  51                 /*
  52                  * Save the R array,
  53                  * which will be the new L.
  54                  */
  55                 for (j = 0; j < 32; j++)
  56                         tempL[j] = R[j];
  57                 /*
  58                  * Expand R to 48 bits using the E selector;
  59                  * exclusive-or with the current key bits.
  60                  */
  61                 for (j = 0; j < 48; j++)
  62                         preS[j] = R[E[j]-1] ^ KS[i][j];
  63                 /*
  64                  * The pre-select bits are now considered
  65                  * in 8 groups of 6 bits each.
  66                  * The 8 selection functions map these
  67                  * 6-bit quantities into 4-bit quantities
  68                  * and the results permuted
  69                  * to make an f(R, K).
  70                  * The indexing into the selection functions
  71                  * is peculiar; it could be simplified by
  72                  * rewriting the tables.
  73                  */
  74                 for (j = 0; j < 8; j++) {
  75                         t = 6*j;
  76                         k = S[j][(preS[t+0]<<5)+
  77                             (preS[t+1]<<3)+
  78                             (preS[t+2]<<2)+
  79                             (preS[t+3]<<1)+
  80                             (preS[t+4]<<0)+
  81                             (preS[t+5]<<4)];
  82                         t = 4*j;
  83                         f[t+0] = (k>>3)&01;
  84                         f[t+1] = (k>>2)&01;
  85                         f[t+2] = (k>>1)&01;
  86                         f[t+3] = (k>>0)&01;
  87                 }
  88                 /*
  89                  * The new R is L ^ f(R, K).
  90                  * The f here has to be permuted first, though.
  91                  */
  92                 for (j = 0; j < 32; j++)
  93                         R[j] = L[j] ^ f[P[j]-1];
  94                 /*
  95                  * Finally, the new L (the original R)
  96                  * is copied back.
  97                  */
  98                 for (j = 0; j < 32; j++)
  99                         L[j] = tempL[j];
 100         }
 101         /*
 102          * The output L and R are reversed.
 103          */
 104         for (j = 0; j < 32; j++) {
 105                 t2 = L[j];
 106                 L[j] = R[j];
 107                 R[j] = t2;
 108         }
 109         /*
 110          * The final output
 111          * gets the inverse permutation of the very original.
 112          */
 113         for (j = 0; j < 64; j++)
 114                 block[j] = L[FP[j]-1];
 115 }