libotp.c

   1 /** Practical One-time Pad Library
   2  *
   3  * Created:20080514
   4  * By Jeff Connelly
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <sysexits.h>
  10 #include <string.h>
  11
  12 #define MARKER_TO "to:"
  13 #define MARKER_BEGIN "--EMOTP_BEGIN--"
  14 #define MARKER_END "--EMOTP_END--"
  15
  16 /** Packaged up encrypted message, ready for transport. */
  17 typedef struct _PACKAGE
  18 {
  19     unsigned long offset;
  20     char *pad_name;
  21     char *cipher_text;
  22 } PACKAGE;
  23
  24 typedef struct _PAD
  25 {
  26     char *local_filename;
  27     char *name;
  28     unsigned long offset;
  29     FILE *fp;
  30     struct _PAD *next;
  31 } PAD;
  32
  33 PAD *pads = NULL;
  34
  35 /** Show a list of all loaded pads. */
  36 void show_pads()
  37 {
  38     PAD *p;
  39
  40     for (p = pads; p; p = p->next)
  41     {
  42         printf("Pad: %s: %s\n", p->name, p->local_filename);
  43     }
  44 }
  45
  46 /** Load a pad file from disk, adding to 'pads' global. */
  47 void load_pad(char *local_filename)
  48 {
  49     FILE *fp;
  50     PAD *new_pad;
  51
  52     fp = fopen("/Volumes/Not Backed Up/otp/otp-dazzlement", "rb");
  53     if (!fp)
  54     {
  55         perror("fopen");
  56         exit(EXIT_FAILURE);
  57     }
  58
  59     new_pad = malloc(sizeof(PAD));
  60     if (!new_pad)
  61     {
  62         perror("malloc");
  63         exit(EX_UNAVAILABLE);
  64     }
  65
  66     new_pad->local_filename = strdup(local_filename);
  67     new_pad->name = strdup("dc"); /* TODO */
  68     new_pad->offset = -1; /* TODO */
  69     new_pad->fp = fp;
  70     new_pad->next = NULL;
  71
  72     /* Add to linked list. */
  73     if (!pads)
  74     {
  75         pads = new_pad;
  76     }
  77     else
  78     {
  79         PAD *p, *tail;
  80
  81         /* Find tail */
  82         for (p = pads; p; p = p->next)
  83             tail = p;
  84         tail->next = new_pad;
  85     }
  86 }
  87
  88 /** Close all pads and free allocated memory. */
  89 void free_pads()
  90 {
  91     PAD *p, *next;
  92
  93     for (p = pads; p; p = next)
  94     {
  95         free(p->name);
  96         free(p->local_filename);
  97         fclose(p->fp);
  98         next = p->next;
  99         free(p);
 100     }
 101 }
 102
 103 int main()
 104 {
 105     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 106     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 107     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 108     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 109     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 110
 111     show_pads();
 112     free_pads();
 113
 114     return 0;
 115 }
 116