How to create a message digest in java?

[KADRI]

Hello friends,
I am last year student. I am working on project, where I am using java as front end. As a part of my project I want to create a message digest. In tried various method but unable to get write answer. Can anyone tell me How to create a message digest in java? Please help me.

[absolute55]

You can easily create a message digest in java using general digester class Digester.

package org.kodejava.example.jasypt;
 
import org.jasypt.util.digest.Digester;
 
import java.util.Arrays;. 
public class DigesterDemo {
   public static void main(String[] args) {
  
       Digester d = new Digester("SHA-1");
       byte[] message = "Hello World from Jasypt".getBytes();
       
        byte[] d1 = d.digest(message);
        System.out.println("Digest = " + new String(d1));
        System.out.println("Digest = " + Arrays.toString(d1));
    }
24.}

[Reegan]

Hey you easily create a message digest using following code. Just go through it.

public static void main(String[] args) throws Exception
  {
     
      MessageDigest mdb = MessageDigest.getInstance("SHA-1");

     
      String orig1 = "And  something  different.";
      byte[] msg1 = orig1.getBytes();

      
      mdb.update(msg1);

      
      byte[] aMessageDigest = mdb.digest();

     
      System.out.println("Original: " + new String(msg1));
      System.out.println("Message Digest: " + new String(aMessageDigest));
  }

[opaper]

Just go to following code and try to understand each line.

include java.security.*;
 byte[] defaultBytes1 = sessionid.getBytes();
try{
	MessageDigest algo = MessageDigest.getInstance("MD5");
	algo.reset();
	algo.update(defaultBytes1);
	byte MD[] = algo.digest();
            
	StringBuffer hexString = new StringBuffer();
	for (int p=0;p<MD.length;p++) {
		hexString.append(Integer.toHexString(0xFF & MD[p]));
	}
	String foo1 = MD.toString();
	System.out.println("sessionid "+sessionid+" md5 version is "+hexString.toString());
	sessionid=hexString+"";
}catch(NoSuchAlgorithmException nsae){
            
}

[MindSpace]

It is very easy process to create a message digest in java. I had written example of it. Just try to understand each step.

import java.security.MessageDigest;
import java.io.FileInputStream;

public class CD {
  public static void main(String[] unused) throws Exception{
  String DF = "CD.java";

  MessageDigest md = MessageDigest.getInstance("SHA1");
  FileInputStream fis1 = new FileInputStream(DF);
  byte[] dataBytes1 = new byte[1024];
  int nread1 = fis1.read(dataBytes1);
  while (nread1 > 0) {
    md.update(dataBytes1, 0, nread);
    nread = fis.read(dataBytes);
  };
  byte[] mdbytes1 = md.digest();
  System.out.println("Digest(in hex):: " + Util.byteArray2Hex(mdbytes1));
  }
}