src/des/weak_key.c

   1 /*
   2  * Copyright 1989 by the Massachusetts Institute of Technology.
   3  *
   4  * For copying and distribution information, please see the file
   5  * <mit-copyright.h>.
   6  *
   7  * Under U.S. law, this software may not be exported outside the US
   8  * without license from the U.S. Commerce department.
   9  *
  10  * These routines form the library interface to the DES facilities.
  11  *
  12  * Originally written 8/85 by Steve Miller, MIT Project Athena.
  13  */
  14
  15 #include <afs/param.h>
  16 #include <afsconfig.h>
  17
  18 RCSID("$Header$");
  19
  20 #include <des.h>
  21 #include "des_internal.h"
  22 #if defined(HAVE_STRINGS_H)
  23 #include <strings.h>
  24 #endif
  25 #if defined(HAVE_STRING_H)
  26 #include <string.h>
  27 #endif
  28
  29 /*
  30  * The following are the weak DES keys:
  31  */
  32 static const des_cblock weak[16] = {
  33     /* weak keys */
  34     {0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01},
  35     {0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe},
  36     {0x1f,0x1f,0x1f,0x1f,0x0e,0x0e,0x0e,0x0e},
  37     {0xe0,0xe0,0xe0,0xe0,0xf1,0xf1,0xf1,0xf1},
  38
  39     /* semi-weak */
  40     {0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe},
  41     {0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01},
  42
  43     {0x1f,0xe0,0x1f,0xe0,0x0e,0xf1,0x0e,0xf1},
  44     {0xe0,0x1f,0xe0,0x1f,0xf1,0x0e,0xf1,0x0e},
  45
  46     {0x01,0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1},
  47     {0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1,0x01},
  48
  49     {0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e,0xfe},
  50     {0xfe,0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e},
  51
  52     {0x01,0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e},
  53     {0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e,0x01},
  54
  55     {0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1,0xfe},
  56     {0xfe,0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1}
  57 };
  58
  59 /*
  60  * des_is_weak_key: returns true iff key is a [semi-]weak des key.
  61  *
  62  * Requires: key has correct odd parity.
  63  */
  64 int
  65 des_is_weak_key(key)
  66      des_cblock key;
  67 {
  68     int i;
  69     const des_cblock *weak_p = weak;
  70
  71     for (i = 0; i < (sizeof(weak)/sizeof(des_cblock)); i++) {
  72         if (!bcmp((char *)weak_p++,(char *)key,sizeof(des_cblock)))
  73             return 1;
  74     }
  75
  76     return 0;
  77 }