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 void add_pad(PAD *new_pad)
  36 {
  37     printf("add %.8X\n", (unsigned int)new_pad);
  38     if (!pads)
  39     {
  40         pads = new_pad;
  41     }
  42     else
  43     {
  44         PAD *p, *tail;
  45
  46         /* Find tail */
  47         for (p = pads; p; p = p->next)
  48             tail = p;
  49         tail->next = new_pad;
  50     }
  51 }
  52
  53 /** Show a list of all loaded pads. */
  54 void show_pads()
  55 {
  56     PAD *p;
  57
  58     for (p = pads; p; p = p->next)
  59     {
  60         printf("Pad: %s: %s (next=%.8x)\n", p->name, p->local_filename,
  61                 (unsigned int)p->next);
  62     }
  63 }
  64
  65 /** Load a pad file from disk, adding to 'pads' global. */
  66 void load_pad(char *local_filename)
  67 {
  68     FILE *fp;
  69     PAD *new_pad;
  70
  71     fp = fopen("/Volumes/Not Backed Up/otp/otp-dazzlement", "rb");
  72     if (!fp)
  73     {
  74         perror("fopen");
  75         exit(EXIT_FAILURE);
  76     }
  77
  78     new_pad = malloc(sizeof(PAD));
  79     if (!new_pad)
  80     {
  81         perror("malloc");
  82         exit(EX_UNAVAILABLE);
  83     }
  84
  85     new_pad->local_filename = strdup(local_filename);
  86     new_pad->name = NULL;
  87     /* TODO: new_pad->offset = */
  88     new_pad->fp = fp;
  89     new_pad->next = NULL;
  90
  91     add_pad(new_pad);
  92 }
  93
  94 /** Close all pads and free allocated memory. */
  95 void free_pads()
  96 {
  97     PAD *p, *next;
  98
  99     for (p = pads; p; p = next)
 100     {
 101         free(p->name);
 102         free(p->local_filename);
 103         fclose(p->fp);
 104         next = p->next;
 105         free(p);
 106     }
 107 }
 108
 109 int main()
 110 {
 111     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 112     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 113     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 114     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 115     load_pad("/Volumes/Not Backed Up/otp/otp-dazzlement");
 116
 117     show_pads();
 118     free_pads();
 119
 120     return 0;
 121 }
 122