/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* Copyright (c) 1988 AT&T */ /* All Rights Reserved */ /* * Copyright 2005 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ /*LINTLIBRARY*/ #include <sys/types.h> void _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) { int i, ii; int t, j, k; char t2; /* * First, permute the bits in the input */ for (j = 0; j < 64; j++) L[j] = block[IP[j]-1]; /* * Perform a decryption operation 16 times. */ for (ii = 0; ii < 16; ii++) { i = 15-ii; /* * Save the R array, * which will be the new L. */ for (j = 0; j < 32; j++) tempL[j] = R[j]; /* * Expand R to 48 bits using the E selector; * exclusive-or with the current key bits. */ for (j = 0; j < 48; j++) preS[j] = R[E[j]-1] ^ KS[i][j]; /* * The pre-select bits are now considered * in 8 groups of 6 bits each. * The 8 selection functions map these * 6-bit quantities into 4-bit quantities * and the results permuted * to make an f(R, K). * The indexing into the selection functions * is peculiar; it could be simplified by * rewriting the tables. */ for (j = 0; j < 8; j++) { t = 6*j; k = S[j][(preS[t+0]<<5)+ (preS[t+1]<<3)+ (preS[t+2]<<2)+ (preS[t+3]<<1)+ (preS[t+4]<<0)+ (preS[t+5]<<4)]; t = 4*j; f[t+0] = (k>>3)&01; f[t+1] = (k>>2)&01; f[t+2] = (k>>1)&01; f[t+3] = (k>>0)&01; } /* * The new R is L ^ f(R, K). * The f here has to be permuted first, though. */ for (j = 0; j < 32; j++) R[j] = L[j] ^ f[P[j]-1]; /* * Finally, the new L (the original R) * is copied back. */ for (j = 0; j < 32; j++) L[j] = tempL[j]; } /* * The output L and R are reversed. */ for (j = 0; j < 32; j++) { t2 = L[j]; L[j] = R[j]; R[j] = t2; } /* * The final output * gets the inverse permutation of the very original. */ for (j = 0; j < 64; j++) block[j] = L[FP[j]-1]; }