Hi Friend,

A one-way hash function is used to create digital signatures, which in turn identify and authenticate the message.

Example:
********************

import java.util.*;
import java.security.*;
public class Hashing {

public static String convert(String st)throws Exception{
byte[] by = st.getBytes();
MessageDigest md = MessageDigest.getInstance("MD5");
md.reset();
md.update(by);
byte messageDigest[] = md.digest();
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < messageDigest.length; i++) {
buffer.append(Integer.toHexString(0xFF & messageDigest[i]));
}
return buffer.toString();
}
public static void main(String[]args)throws Exception{
Scanner input=new Scanner(System.in);
System.out.print("Enter text: ");
String text=input.nextLine();

String st=Hashing.convert(text);
System.out.println(st);
}
}

Thanks