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 /*LINTLIBRARY*/ 32 33 #include <sys/types.h> 34 35 void 36 _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) 37 { 38 int i, ii; 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 a decryption operation 16 times. 49 */ 50 for (ii = 0; ii < 16; ii++) { 51 i = 15-ii; 52 /* 53 * Save the R array, 54 * which will be the new L. 55 */ 56 for (j = 0; j < 32; j++) 57 tempL[j] = R[j]; 58 /* 59 * Expand R to 48 bits using the E selector; 60 * exclusive-or with the current key bits. 61 */ 62 for (j = 0; j < 48; j++) 63 preS[j] = R[E[j]-1] ^ KS[i][j]; 64 /* 65 * The pre-select bits are now considered 66 * in 8 groups of 6 bits each. 67 * The 8 selection functions map these 68 * 6-bit quantities into 4-bit quantities 69 * and the results permuted 70 * to make an f(R, K). 71 * The indexing into the selection functions 72 * is peculiar; it could be simplified by 73 * rewriting the tables. 74 */ 75 for (j = 0; j < 8; j++) { 76 t = 6*j; 77 k = S[j][(preS[t+0]<<5)+ 78 (preS[t+1]<<3)+ 79 (preS[t+2]<<2)+ 80 (preS[t+3]<<1)+ 81 (preS[t+4]<<0)+ 82 (preS[t+5]<<4)]; 83 t = 4*j; 84 f[t+0] = (k>>3)&01; 85 f[t+1] = (k>>2)&01; 86 f[t+2] = (k>>1)&01; 87 f[t+3] = (k>>0)&01; 88 } 89 /* 90 * The new R is L ^ f(R, K). 91 * The f here has to be permuted first, though. 92 */ 93 for (j = 0; j < 32; j++) 94 R[j] = L[j] ^ f[P[j]-1]; 95 /* 96 * Finally, the new L (the original R) 97 * is copied back. 98 */ 99 for (j = 0; j < 32; j++) 100 L[j] = tempL[j]; 101 } 102 /* 103 * The output L and R are reversed. 104 */ 105 for (j = 0; j < 32; j++) { 106 t2 = L[j]; 107 L[j] = R[j]; 108 R[j] = t2; 109 } 110 /* 111 * The final output 112 * gets the inverse permutation of the very original. 113 */ 114 for (j = 0; j < 64; j++) 115 block[j] = L[FP[j]-1]; 116 } 117