Converting a byte array or hex string into DES key

Question

i required to covert a hex represented of DES key into key object for cryptography operation to performed ...
can you help me to find out how to convert a hex representaion of key int DES key object

Answer 1

hi friend,
I think the key size is more than the required size. For DES algorithm, the key size is 64 bit long.But the code u have given has more than 64 bit, because of which this exception has been raised.
Reduce the key value to 64bit and try. If it doesnt work,try the code given below .I think it might be helpful for u
import javax.crypto.*;
import javax.crypto.spec.*;
public class Cryption
     public byte[] encrypt(byte[] keyData,byte[] clearMessage)
          try
               SecretKeySpec sks = new SecretKeySpec(keyData,"DES");
               Cipher c = Cipher.getInstance ("DES");
               c.init(Cipher.ENCRYPT_MODE,sks);
               byte[] encryptedMessage = c.doFinal(clearMessage);
               return encryptedMessage;
          catch(Exception e)
               e.printStackTrace();
          return null;
     public byte[] decrypt(byte[] keyData,byte[] cipherMessage)
          try
               SecretKeySpec sks = new SecretKeySpec(keyData,"DES");
               Cipher c = Cipher.getInstance ("DES");
               c.init(Cipher.DECRYPT_MODE,sks);
               byte[] decryptedMessage = c.doFinal(cipherMessage);
               return decryptedMessage;
          catch(Exception e)
               e.printStackTrace();
          return null;
     public static void main(String[] args)
          String keyString = "ABCDEF12";
          byte keyValue[] = keyString.getBytes();
          Cryption encryption = new Cryption();
          String Message = "Hello Welcome to world of Cryptography";
          System.out.println("Key Value (represented in HEX form): "+keyString);
          System.out.println("Key Value (represented in byte array form): "+keyValue);
          System.out.println("Original Message : "+Message);
          byte[] encryptedMessage = encryption.encrypt(keyValue,Message.getBytes());
          System.out.println("Encrypted Message : "+new String(encryptedMessage));
          Cryption decryption = new Cryption();
          byte[] decryptedMessage = decryption.decrypt(keyValue,encryptedMessage);
          System.out.println("Decrypted Message : "+new String(decryptedMessage));
output :
Key Value (represented in HEX form): ABCDEF12
Key Value (represented in byte array form): [B@43c749
Original Message : Hello Welcome to world of Cryptography
Encrypted Message : "O3�?�M�,����������,�]�3�����R�?>C$
Decrypted Message : Hello Welcome to world of Cryptography
whenever u use any algorithm, first findout the key size or range that algorithm supports. It is very important
regards,
Deepa Raghuraman