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 <afsconfig.h>
  16 #include <afs/param.h>
  17
  18 RCSID("$Header$");
  19
  20 #include <des.h>
  21 #include "des_internal.h"
  22 #ifdef HAVE_STRING_H
  23 #include <string.h>
  24 #else
  25 #ifdef HAVE_STRINGS_H
  26 #include <strings.h>
  27 #endif
  28 #endif
  29
  30 /*
  31  * The following are the weak DES keys:
  32  */
  33 static const des_cblock weak[16] = {
  34     /* weak keys */
  35     {0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01},
  36     {0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe},
  37     {0x1f,0x1f,0x1f,0x1f,0x0e,0x0e,0x0e,0x0e},
  38     {0xe0,0xe0,0xe0,0xe0,0xf1,0xf1,0xf1,0xf1},
  39
  40     /* semi-weak */
  41     {0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe},
  42     {0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01},
  43
  44     {0x1f,0xe0,0x1f,0xe0,0x0e,0xf1,0x0e,0xf1},
  45     {0xe0,0x1f,0xe0,0x1f,0xf1,0x0e,0xf1,0x0e},
  46
  47     {0x01,0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1},
  48     {0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1,0x01},
  49
  50     {0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e,0xfe},
  51     {0xfe,0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e},
  52
  53     {0x01,0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e},
  54     {0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e,0x01},
  55
  56     {0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1,0xfe},
  57     {0xfe,0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1}
  58 };
  59
  60 /*
  61  * des_is_weak_key: returns true iff key is a [semi-]weak des key.
  62  *
  63  * Requires: key has correct odd parity.
  64  */
  65 int
  66 des_is_weak_key(key)
  67      des_cblock key;
  68 {
  69     int i;
  70     const des_cblock *weak_p = weak;
  71
  72     for (i = 0; i < (sizeof(weak)/sizeof(des_cblock)); i++) {
  73         if (!bcmp((char *)weak_p++,(char *)key,sizeof(des_cblock)))
  74             return 1;
  75     }
  76
  77     return 0;
  78 }