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 /* EXPORT DELETE START */ 40 int i, ii; 41 int t, j, k; 42 char t2; 43 44 /* 45 * First, permute the bits in the input 46 */ 47 for (j = 0; j < 64; j++) 48 L[j] = block[IP[j]-1]; 49 /* 50 * Perform a decryption operation 16 times. 51 */ 52 for (ii = 0; ii < 16; ii++) { 53 i = 15-ii; 54 /* 55 * Save the R array, 56 * which will be the new L. 57 */ 58 for (j = 0; j < 32; j++) 59 tempL[j] = R[j]; 60 /* 61 * Expand R to 48 bits using the E selector; 62 * exclusive-or with the current key bits. 63 */ 64 for (j = 0; j < 48; j++) 65 preS[j] = R[E[j]-1] ^ KS[i][j]; 66 /* 67 * The pre-select bits are now considered 68 * in 8 groups of 6 bits each. 69 * The 8 selection functions map these 70 * 6-bit quantities into 4-bit quantities 71 * and the results permuted 72 * to make an f(R, K). 73 * The indexing into the selection functions 74 * is peculiar; it could be simplified by 75 * rewriting the tables. 76 */ 77 for (j = 0; j < 8; j++) { 78 t = 6*j; 79 k = S[j][(preS[t+0]<<5)+ 80 (preS[t+1]<<3)+ 81 (preS[t+2]<<2)+ 82 (preS[t+3]<<1)+ 83 (preS[t+4]<<0)+ 84 (preS[t+5]<<4)]; 85 t = 4*j; 86 f[t+0] = (k>>3)&01; 87 f[t+1] = (k>>2)&01; 88 f[t+2] = (k>>1)&01; 89 f[t+3] = (k>>0)&01; 90 } 91 /* 92 * The new R is L ^ f(R, K). 93 * The f here has to be permuted first, though. 94 */ 95 for (j = 0; j < 32; j++) 96 R[j] = L[j] ^ f[P[j]-1]; 97 /* 98 * Finally, the new L (the original R) 99 * is copied back. 100 */ 101 for (j = 0; j < 32; j++) 102 L[j] = tempL[j]; 103 } 104 /* 105 * The output L and R are reversed. 106 */ 107 for (j = 0; j < 32; j++) { 108 t2 = L[j]; 109 L[j] = R[j]; 110 R[j] = t2; 111 } 112 /* 113 * The final output 114 * gets the inverse permutation of the very original. 115 */ 116 for (j = 0; j < 64; j++) 117 block[j] = L[FP[j]-1]; 118 /* EXPORT DELETE END */ 119 } 120