To calculate cryptographic hashing value in Java, MessageDigest Class is used, under the package java.security.
MessageDigest Class provides following cryptographic hash function to find hash value of a text, they are:
- MD5
- SHA-1
- SHA-256
This Algorithms are initialize in static method called getInstance(). After selecting the algorithm it calculate the digest value and return the results in byte array.
BigInteger class is used, which converts the resultant byte array into its sign-magnitude representation.
This representation converts into hex format to get the MessageDigest
Examples:
Input : hello world Output : 5eb63bbbe01eeed093cb22bb8f5acdc3 Input : GeeksForGeeks Output : e39b9c178b2c9be4e99b141d956c6ff6
Implementation:
Java
import java.math.BigInteger;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;// Java program to calculate MD5 hash valuepublic class MD5 { public static String getMd5(String input) { try { // Static getInstance method is called with hashing MD5 MessageDigest md = MessageDigest.getInstance("MD5"); // digest() method is called to calculate message digest // of an input digest() return array of byte byte[] messageDigest = md.digest(input.getBytes()); // Convert byte array into signum representation BigInteger no = new BigInteger(1, messageDigest); // Convert message digest into hex value String hashtext = no.toString(16); while (hashtext.length() < 32) { hashtext = "0" + hashtext; } return hashtext; } // For specifying wrong message digest algorithms catch (NoSuchAlgorithmException e) { throw new RuntimeException(e); } } // Driver code public static void main(String args[]) throws NoSuchAlgorithmException { String s = "GeeksForGeeks"; System.out.println("Your HashCode Generated by MD5 is: " + getMd5(s)); }} |
Output
Your HashCode Generated by MD5 is: e39b9c178b2c9be4e99b141d956c6ff6
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