MD5 and RSA - Slow performance - Help / Views Required

Question

Hi,
I am facing a problem while signing a message.The
scenario is:
I have to create 20,000 messages to be sent to
clients. I am encrypting the message using MD5 and
RSA.
But when i am encrypting via RSA it takes about 20
mins to encrypt the 20k messages.I dont know why its
taking so much time. I have max 4-5 mins to manipulate
and send messages. The sample code is as follows:
ur earliest help will be quite helpful.
Thanks in advance
Hassan
************** Source Code ****************
import java.io.IOException;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.MessageDigest;
import java.security.Signature;
import java.security.PrivateKey;
import java.security.spec.RSAPrivateKeySpec;
import org.apache.log4j.Logger;
public class Signer {
******************************************

Answer 1

Hi Sabre,
I have compiled the simple code from JCE tutorial for DES. The output text it is showing is different than input text.
Is there any problem going on in tutorial's example ?
Regards
Hamid
******** output **************
the original cleartext is: [B@13a328f
the encrypted text is: [B@337838
the final cleartext is: [B@119cca4
******** Code ************
public class jCypher {
private static Cipher desCipher = null;
public static void main (String[] args) throws NoSuchAlgorithmException,
InvalidKeyException, IllegalBlockSizeException, NoSuchProviderException,
BadPaddingException, NoSuchPaddingException, Exception
//Creating a Key Generator and Generating a Key
//public static KeyGenerator getInstance(String algorithm);
KeyGenerator keygen = KeyGenerator.getInstance("DES");
SecretKey desKey = keygen.generateKey();
// Creating a Cipher
// Cipher.getInstance(Transformation);     
// c1 = Cipher.getInstance("RSA/ECB/PKCS1Padding");     
desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
// Cipher.init(int opmode, Key key);
desCipher.init(Cipher.ENCRYPT_MODE, desKey );
// Cleartext
byte[] cleartext = "This is small Text for testing".getBytes();
System.out.println("the original cleartext is: " + cleartext.toString());
// Encrypt the cleartext
// encrypted or decrypted data in one step (single-part operation)
// public byte[] doFinal(byte[] input);
byte[] ciphertext = desCipher.doFinal(cleartext);
System.out.println("the encrypted text is: " + ciphertext.toString());
// Initialize the same cipher for decryption
desCipher.init(Cipher.DECRYPT_MODE, desKey );
// Decrypt the ciphertext
byte[] cleartext1 = desCipher.doFinal(ciphertext);
System.out.println("the final cleartext is: " + cleartext1.toString());
} // End main()
}