Question

Can someone please show me an example usage of Schneier’s Blowfish code (http://www.schneier.com/code/bfsh-sch.zip), i.e. encrypting and decrypting a string with a given key, in C or C++?

Thanks in advance.

Edit: this is not a homework assignment.

Answer 1

Here is a test

#include <stdio.h>
#include "blowfish.h"
#include <string.h>

int main(void)
{
  unsigned long xl = 1, xr = 2;
  char key[] = "Hello";


  /* NoErr is defined as 0 in the blowfish.c file */
  if (opensubkeyfile () != 0)
  {
    printf ("\nCannot open subkey file");
    perror ("Exit");
    printf ("\n");
    return 1;
  };

  InitializeBlowfish (key, 7);
  Blowfish_encipher (&xl, &xr);

  printf("\n%x %x", xl, xr);

  Blowfish_decipher (&xl, &xr);

  printf("\n%x %x", xl, xr);

  if ((xl == 1) && (xr == 2))
  {
    printf("\nDecipher OK.");
  }
  else
  {
    printf("\nDecipher Fail\n");
  }
  printf ("\n");
  return 0;
}

Please make sure the header file name’s character case. Also note the file name blowfish.dat is correct.

Also have a look at Paul Kocher’s Implementation from this page : http://www.schneier.com/blowfish-download.html