RE: Really simple DES encryption

[Samuel Mota]

Hi,

Thanks Jeffrey. A few more newbie questions :)

For ECB mode the initialization vector is not used or it`s fixed somewhere?
(http://www.tropsoft.com/strongenc/des.htm;)
The simplest programm I wrote is encrypting and decrypting the message, but the 
encrypted does not
match with the expected (from the vendor test case application). The first 2 
bytes matches, but
after that they are different. Any idea?

My App output:
Plain text is:
0x6 0x12 0x34 0x56 0xff 0xff 0xff 0xff
Cipher text is:
0x21 0x79 0xad 0xb9 0x24 0x59 0xee 0xe3
Decrypted text is:
0x6 0x12 0x34 0x56 0xff 0xff 0xff 0xff

The expected encrypted text is: 0x21 0x79 0x53 0xE1 0xC7 0xB1 0x72 0xAD

My source code:
#include "modes.h"
#include "des.h"
#include "hex.h"

#include <iostream>
#include <time.h>

#include <windows.h>

USING_NAMESPACE(CryptoPP)
USING_NAMESPACE(std)

int main()
{
      //declare help variables
      register int i;
      const unsigned int blocksize = 8;

      //declare key and plain text vector
      const byte key[] =
            { 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61 };
      byte plaintext[] =
            { 0x06, 0x12, 0x34, 0x56, 0xFF, 0xFF, 0xFF, 0xFF };

      //declare vectors to hole encrypted and decrypted messages
      byte *ciphertext;
      ciphertext = new byte[blocksize];
      byte *decryptedtext;
      decryptedtext = new byte[blocksize];

      //declare encryption and decryption objects
      ECB_Mode<DES>::Encryption ecbEncryption(key, DES::DEFAULT_KEYLENGTH, 
NULL);
      ECB_Mode<DES>::Decryption ecbDecryption(key, DES::DEFAULT_KEYLENGTH, 
NULL);

      //show plain text contents
      printf("Plain text is:\n");
      for(i=0; i<blocksize; i++) {
            printf("%#x ", plaintext[i]);
      }

      //encrypt
      ecbEncryption.ProcessData(ciphertext, plaintext, blocksize);

      //show encrypted message
      printf("\nCipher text is:\n");
      for(i=0; i<blocksize; i++) {
            printf("%#x ", ciphertext[i]);
      }

      //decrypt
      ecbDecryption.ProcessData(decryptedtext, ciphertext, blocksize);

      printf("\nDecrypted text is:\n");
      for(i=0; i<blocksize; i++) {
            printf("%#x ", decryptedtext[i]);
      }

      free(ciphertext);
      free(decryptedtext);

      return 0;
}

+ Samuel G. Mota
+ [EMAIL PROTECTED]
+ 55 (11) 4417 7093
+ Business Application Dpt.
+ Netset Servi�os em Tecnologia
+ a Hypercom Company
+ http://www.hypercom.com