1 /* 2 * lib/crypto/des/weak_key.c 3 * 4 * Copyright 1989,1990 by the Massachusetts Institute of Technology. 5 * All Rights Reserved. 6 * 7 * Export of this software from the United States of America may 8 * require a specific license from the United States Government. 9 * It is the responsibility of any person or organization contemplating 10 * export to obtain such a license before exporting. 11 * 12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 13 * distribute this software and its documentation for any purpose and 14 * without fee is hereby granted, provided that the above copyright 15 * notice appear in all copies and that both that copyright notice and 16 * this permission notice appear in supporting documentation, and that 17 * the name of M.I.T. not be used in advertising or publicity pertaining 18 * to distribution of the software without specific, written prior 19 * permission. Furthermore if you modify this software you must label 20 * your software as modified software and not distribute it in such a 21 * fashion that it might be confused with the original M.I.T. software. 22 * M.I.T. makes no representations about the suitability of 23 * this software for any purpose. It is provided "as is" without express 24 * or implied warranty. 25 * 26 * 27 * Under U.S. law, this software may not be exported outside the US 28 * without license from the U.S. Commerce department. 29 * 30 * These routines form the library interface to the DES facilities. 31 * 32 * Originally written 8/85 by Steve Miller, MIT Project Athena. 33 */ 34 35 #include "k5-int.h" 36 #include "des_int.h" 37 38 /* 39 * The following are the weak DES keys: 40 */ 41 static const mit_des_cblock weak[16] = { 42 /* weak keys */ 43 {0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01}, 44 {0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe}, 45 {0x1f,0x1f,0x1f,0x1f,0x0e,0x0e,0x0e,0x0e}, 46 {0xe0,0xe0,0xe0,0xe0,0xf1,0xf1,0xf1,0xf1}, 47 48 /* semi-weak */ 49 {0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe}, 50 {0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01}, 51 52 {0x1f,0xe0,0x1f,0xe0,0x0e,0xf1,0x0e,0xf1}, 53 {0xe0,0x1f,0xe0,0x1f,0xf1,0x0e,0xf1,0x0e}, 54 55 {0x01,0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1}, 56 {0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1,0x01}, 57 58 {0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e,0xfe}, 59 {0xfe,0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e}, 60 61 {0x01,0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e}, 62 {0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e,0x01}, 63 64 {0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1,0xfe}, 65 {0xfe,0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1} 66 }; 67 68 /* 69 * mit_des_is_weak_key: returns true iff key is a [semi-]weak des key. 70 * 71 * Requires: key has correct odd parity. 72 */ 73 int 74 mit_des_is_weak_key(mit_des_cblock key) 75 { 76 int i; 77 const mit_des_cblock *weak_p = weak; 78 79 for (i = 0; i < (sizeof(weak)/sizeof(mit_des_cblock)); i++) { 80 if (!memcmp(weak_p++,key,sizeof(mit_des_cblock))) 81 return 1; 82 } 83 84 return 0; 85 } 86