Using libgcrypt1.2.0 for 3DES, ECB mode of encryption/decryption.

[Madhavi.Gandavarapu at equifax.com]

Hi,

I have a string that I am trying to encrypt using 3DES,ECB mode.  I have a
specific 24 byte key that I need to use to encrypt or decrypt.
I am not getting good encrypted string back, since I can't even decrypt what I
encrypted with the same key and same library.

Can you point me to what I am doing wrong here.

Here is the code segment.



unsigned char enc_key[24] =
{0x12,0x34,0x51,0x23,0x45,0x12,0x34,0x51,0x15,0x43,0x21,0x54,0x32,0x15,0x43,0x21,0x45,0x12,0x34,0x51,0x12,
0x34,0x51,0x23};


static int do_encrypt(unsigned char* dest,unsigned char* src)
{
   //GCRY_CIPHER_3DES is the algorithm type
   //GCRY_CIPHER_MODE_ECB is the algorithem mode
   //0(zero) is the flags value to send
   int retVal =0;
   gcry_cipher_hd_t hd;

   int keylen;
   int i =0,x=0;
   gcry_error_t err = 0;

   keylen = gcry_cipher_get_algo_keylen(GCRY_CIPHER_3DES);
   if (!keylen)
   {
//    fail ("algo %d, mode %d, gcry_cipher_get_algo_keylen failed\n", algo,
mode);
      logf(&bLog, LF_ERROR, "algo %s, mode %s, gcry_cipher_get_algo_keylen
failed","GCRY_CIPHER_3DES" ,"GCRY_CIPHER_MODE_ECB" );
      retVal = -1;
      return retVal;
   }
   if (keylen < 40 / 8 || keylen > 32)
   {
//    fail ("algo %d, mode %d, keylength problem (%d)\n", algo, mode, keylen);
      logf(&bLog, LF_ERROR, "algo %s, mode %s, keylength problem
(%d)","GCRY_CIPHER_3DES" ,"GCRY_CIPHER_MODE_ECB",keylen );
      retVal = -1;
      return retVal;
   }
   err = gcry_cipher_open (&hd, GCRY_CIPHER_3DES, GCRY_CIPHER_MODE_ECB, 0);
   if (err)
   {
//    fail ("algo %d, mode %d, grcy_open_cipher failed: %s\n", algo, mode,
gpg_strerror (err));
      logf(&bLog, LF_ERROR, "algo %s, mode %s, grcy_open_cipher failed:
%s","GCRY_CIPHER_3DES" ,"GCRY_CIPHER_MODE_ECB",gpg_strerror(err)
);
      return err;

 }
   err = gcry_cipher_setkey (hd, &enc_key, keylen);
   if (err)
   {
//    fail ("algo %d, mode %d, gcry_cipher_setkey failed: %s\n",  algo, mode,
gpg_strerror (err));
      logf(&bLog, LF_ERROR, "algo %s, mode %s, gcry_cipher_setkey failed:
%s","GCRY_CIPHER_3DES" ,"GCRY_CIPHER_MODE_ECB",gpg_strerror(er
r));
      gcry_cipher_close (hd);
      return err;
   }
   //err = gcry_cipher_encrypt (hd, dest, strlen(dest), NULL,strlen(dest));
   err = gcry_cipher_encrypt (hd, dest, strlen(dest), src, strlen(src));
   if (err)
   {
//    fail ("algo %d, mode %d, gcry_cipher_encrypt failed: %s\n", algo, mode,
gpg_strerror (err));
      logf(&bLog, LF_ERROR, "algo %s, mode %s, gcry_cipher_encrypt failed:
%s","GCRY_CIPHER_3DES" ,"GCRY_CIPHER_MODE_ECB",gpg_strerror(e
rr));
      gcry_cipher_close (hd);
      return err;
   }
   i =0; x=0;
   if((x = (strlen(dest)%bsize)))
   {
      x = (bsize - x);
      for(i = 0; i < x; i++)
         strcat(dest," ");
   }

   err = gcry_cipher_decrypt (hd, dest, strlen(dest), dest, strlen(dest));
   if (err)
   {
//    fail ("algo %d, mode %d, gcry_cipher_decrypt failed: %s\n", algo, mode,
gpg_strerror (err));
      logf(&bLog, LF_ERROR, "algo %s, mode %s, gcry_cipher_decrypt failed:
%s","GCRY_CIPHER_3DES" ,"GCRY_CIPHER_MODE_ECB",gpg_strerror(e
rr));
      gcry_cipher_close (hd);
      return err;
   }


   gcry_cipher_close (hd);






Thanks and Regards
Madhavi
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