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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* Copyright (c) 1988 AT&T */ 23 /* All Rights Reserved */ 24 25 26 /* 27 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 28 * Use is subject to license terms. 29 */ 30 31 #pragma ident "%Z%%M% %I% %E% SMI" 32 /*LINTLIBRARY*/ 33 34 #include <sys/types.h> 35 36 void 37 _des_decrypt1(char *block, char *L, char *IP, char *R, char *preS, char *E, char KS[][48], char S[][64], char *f, char *tempL, char *P, char *FP) 38 { 39 int i, ii; 40 int t, j, k; 41 char t2; 42 43 /* 44 * First, permute the bits in the input 45 */ 46 for (j = 0; j < 64; j++) 47 L[j] = block[IP[j]-1]; 48 /* 49 * Perform a decryption operation 16 times. 50 */ 51 for (ii = 0; ii < 16; ii++) { 52 i = 15-ii; 53 /* 54 * Save the R array, 55 * which will be the new L. 56 */ 57 for (j = 0; j < 32; j++) 58 tempL[j] = R[j]; 59 /* 60 * Expand R to 48 bits using the E selector; 61 * exclusive-or with the current key bits. 62 */ 63 for (j = 0; j < 48; j++) 64 preS[j] = R[E[j]-1] ^ KS[i][j]; 65 /* 66 * The pre-select bits are now considered 67 * in 8 groups of 6 bits each. 68 * The 8 selection functions map these 69 * 6-bit quantities into 4-bit quantities 70 * and the results permuted 71 * to make an f(R, K). 72 * The indexing into the selection functions 73 * is peculiar; it could be simplified by 74 * rewriting the tables. 75 */ 76 for (j = 0; j < 8; j++) { 77 t = 6*j; 78 k = S[j][(preS[t+0]<<5)+ 79 (preS[t+1]<<3)+ 80 (preS[t+2]<<2)+ 81 (preS[t+3]<<1)+ 82 (preS[t+4]<<0)+ 83 (preS[t+5]<<4)]; 84 t = 4*j; 85 f[t+0] = (k>>3)&01; 86 f[t+1] = (k>>2)&01; 87 f[t+2] = (k>>1)&01; 88 f[t+3] = (k>>0)&01; 89 } 90 /* 91 * The new R is L ^ f(R, K). 92 * The f here has to be permuted first, though. 93 */ 94 for (j = 0; j < 32; j++) 95 R[j] = L[j] ^ f[P[j]-1]; 96 /* 97 * Finally, the new L (the original R) 98 * is copied back. 99 */ 100 for (j = 0; j < 32; j++) 101 L[j] = tempL[j]; 102 } 103 /* 104 * The output L and R are reversed. 105 */ 106 for (j = 0; j < 32; j++) { 107 t2 = L[j]; 108 L[j] = R[j]; 109 R[j] = t2; 110 } 111 /* 112 * The final output 113 * gets the inverse permutation of the very original. 114 */ 115 for (j = 0; j < 64; j++) 116 block[j] = L[FP[j]-1]; 117 }