view libtomcrypt/demos/ltcrypt.c @ 1663:c795520269f9

Fallback for key gen without hard link support (#89) Add a non-atomic fallback for key generation on platforms where link() is not permitted (such as most stock Android installs) or on filesystems without hard link support (such as FAT).
author Matt Robinson <git@nerdoftheherd.com>
date Sat, 14 Mar 2020 14:37:35 +0000
parents 6dba84798cd5
children
line wrap: on
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */

/* encrypt V1.1 Fri Oct 18 04:28:03 NZDT 2002 */
/* File de/encryption, using libtomcrypt */
/* Written by Daniel Richards <[email protected]> */
/* Help from Tom St Denis with various bits */
/* This code is public domain, no rights reserved. */
/* Encrypts by default, -d flag enables decryption */
/* ie: ./encrypt blowfish story.txt story.ct */
/* ./encrypt -d blowfish story.ct story.pt */

#include <tomcrypt.h>

int usage(char *name)
{
   int x;

   printf("Usage encrypt: %s cipher infile outfile\n", name);
   printf("Usage decrypt: %s -d cipher infile outfile\n", name);
   printf("Usage test:    %s -t cipher\nCiphers:\n", name);
   for (x = 0; cipher_descriptor[x].name != NULL; x++) {
      printf("%s\n",cipher_descriptor[x].name);
   }
   exit(1);
}

int main(int argc, char *argv[])
{
   unsigned char plaintext[512],ciphertext[512];
   unsigned char tmpkey[512], key[MAXBLOCKSIZE], IV[MAXBLOCKSIZE];
   unsigned char inbuf[512]; /* i/o block size */
   unsigned long outlen, y, ivsize, x, decrypt;
   symmetric_CTR ctr;
   int cipher_idx, hash_idx, ks;
   char *infile, *outfile, *cipher;
   prng_state prng;
   FILE *fdin, *fdout;
   int err;

   /* register algs, so they can be printed */
   register_all_ciphers();
   register_all_hashes();
   register_all_prngs();

   if (argc < 4) {
      if ((argc > 2) && (!strcmp(argv[1], "-t"))) {
        cipher  = argv[2];
        cipher_idx = find_cipher(cipher);
        if (cipher_idx == -1) {
          printf("Invalid cipher %s entered on command line.\n", cipher);
          exit(-1);
        } /* if */
        if (cipher_descriptor[cipher_idx].test)
        {
          if (cipher_descriptor[cipher_idx].test() != CRYPT_OK)
          {
            printf("Error when testing cipher %s.\n", cipher);
            exit(-1);
          }
          else
          {
            printf("Testing cipher %s succeeded.\n", cipher);
            exit(0);
          } /* if ... else */
        } /* if */
      }
      return usage(argv[0]);
   }

   if (!strcmp(argv[1], "-d")) {
      decrypt = 1;
      cipher  = argv[2];
      infile  = argv[3];
      outfile = argv[4];
   } else {
      decrypt = 0;
      cipher  = argv[1];
      infile  = argv[2];
      outfile = argv[3];
   }

   /* file handles setup */
   fdin = fopen(infile,"rb");
   if (fdin == NULL) {
      perror("Can't open input for reading");
      exit(-1);
   }

   fdout = fopen(outfile,"wb");
   if (fdout == NULL) {
      perror("Can't open output for writing");
      exit(-1);
   }

   cipher_idx = find_cipher(cipher);
   if (cipher_idx == -1) {
      printf("Invalid cipher entered on command line.\n");
      exit(-1);
   }

   hash_idx = find_hash("sha256");
   if (hash_idx == -1) {
      printf("LTC_SHA256 not found...?\n");
      exit(-1);
   }

   ivsize = cipher_descriptor[cipher_idx].block_length;
   ks = hash_descriptor[hash_idx].hashsize;
   if (cipher_descriptor[cipher_idx].keysize(&ks) != CRYPT_OK) {
      printf("Invalid keysize???\n");
      exit(-1);
   }

   printf("\nEnter key: ");
   if(fgets((char *)tmpkey,sizeof(tmpkey), stdin) == NULL)
      exit(-1);
   outlen = sizeof(key);
   if ((err = hash_memory(hash_idx,tmpkey,strlen((char *)tmpkey),key,&outlen)) != CRYPT_OK) {
      printf("Error hashing key: %s\n", error_to_string(err));
      exit(-1);
   }

   if (decrypt) {
      /* Need to read in IV */
      if (fread(IV,1,ivsize,fdin) != ivsize) {
         printf("Error reading IV from input.\n");
         exit(-1);
      }

      if ((err = ctr_start(cipher_idx,IV,key,ks,0,CTR_COUNTER_LITTLE_ENDIAN,&ctr)) != CRYPT_OK) {
         printf("ctr_start error: %s\n",error_to_string(err));
         exit(-1);
      }

      /* IV done */
      do {
         y = fread(inbuf,1,sizeof(inbuf),fdin);

         if ((err = ctr_decrypt(inbuf,plaintext,y,&ctr)) != CRYPT_OK) {
            printf("ctr_decrypt error: %s\n", error_to_string(err));
            exit(-1);
         }

         if (fwrite(plaintext,1,y,fdout) != y) {
            printf("Error writing to file.\n");
            exit(-1);
         }
      } while (y == sizeof(inbuf));
      fclose(fdin);
      fclose(fdout);

   } else {  /* encrypt */
      /* Setup yarrow for random bytes for IV */

      if ((err = rng_make_prng(128, find_prng("yarrow"), &prng, NULL)) != CRYPT_OK) {
         printf("Error setting up PRNG, %s\n", error_to_string(err));
      }

      /* You can use rng_get_bytes on platforms that support it */
      /* x = rng_get_bytes(IV,ivsize,NULL);*/
      x = yarrow_read(IV,ivsize,&prng);
      if (x != ivsize) {
         printf("Error reading PRNG for IV required.\n");
         exit(-1);
      }

      if (fwrite(IV,1,ivsize,fdout) != ivsize) {
         printf("Error writing IV to output.\n");
         exit(-1);
      }

      if ((err = ctr_start(cipher_idx,IV,key,ks,0,CTR_COUNTER_LITTLE_ENDIAN,&ctr)) != CRYPT_OK) {
         printf("ctr_start error: %s\n",error_to_string(err));
         exit(-1);
      }

      do {
         y = fread(inbuf,1,sizeof(inbuf),fdin);

         if ((err = ctr_encrypt(inbuf,ciphertext,y,&ctr)) != CRYPT_OK) {
            printf("ctr_encrypt error: %s\n", error_to_string(err));
            exit(-1);
         }

         if (fwrite(ciphertext,1,y,fdout) != y) {
            printf("Error writing to output.\n");
            exit(-1);
         }
      } while (y == sizeof(inbuf));
      fclose(fdout);
      fclose(fdin);
   }
   return 0;
}

/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */