Using SHA1 Message Digest in Java

This section provides a tutorial example on how to use SHA1 message digest algorithm in Java. The JDK JCE package offers the SHA1 algorithm through a generic message digest class, javax.security.MessageDigest.

Sun provides SHA1 algorithm in Java under their JCE (Java Cryptography Extension) package, which is included in JDK 1.5 and newer versions.

Sun's implementation of SHA1 can be accessed through a generic class called MessageDigest. Here are the main methods of MessageDigest class:

Here is a sample Java program to show you how to use the MessageDigest class to perform some tests on SHA1 algorithms.

/* JceSha1Test.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.security.*;
class JceSha1Test {
   public static void main(String[] a) {
      try {
         MessageDigest md = MessageDigest.getInstance("SHA1");
         System.out.println("Message digest object info: ");
         System.out.println("   Algorithm = "+md.getAlgorithm());
         System.out.println("   Provider = "+md.getProvider());
         System.out.println("   toString = "+md.toString());

         String input = "";
         md.update(input.getBytes()); 
         byte[] output = md.digest();
         System.out.println();
         System.out.println("SHA1(\""+input+"\") =");
         System.out.println("   "+bytesToHex(output));

         input = "abc";
         md.update(input.getBytes()); 
         output = md.digest();
         System.out.println();
         System.out.println("SHA1(\""+input+"\") =");
         System.out.println("   "+bytesToHex(output));

         input = "abcdefghijklmnopqrstuvwxyz";
         md.update(input.getBytes()); 
         output = md.digest();
         System.out.println();
         System.out.println("SHA1(\""+input+"\") =");
         System.out.println("   "+bytesToHex(output));
         
      } catch (Exception e) {
         System.out.println("Exception: "+e);
      }
   }
   public static String bytesToHex(byte[] b) {
      char hexDigit[] = {'0', '1', '2', '3', '4', '5', '6', '7',
                         '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
      StringBuffer buf = new StringBuffer();
      for (int j=0; j<b.length; j++) {
         buf.append(hexDigit[(b[j] >> 4) & 0x0f]);
         buf.append(hexDigit[b[j] & 0x0f]);
      }
      return buf.toString();
   }
}

If you run this sample program, you should get the following output:

herong> javac JceSha1Test.java

herong> java JceSha1Test
Message digest object info:
   Algorithm = SHA1
   Provider = SUN version 1.5
   toString = SHA1 Message Digest from SUN, <initialized>

SHA1("") =
   DA39A3EE5E6B4B0D3255BFEF95601890AFD80709

SHA1("abc") =
   A9993E364706816ABA3E25717850C26C9CD0D89D

SHA1("abcdefghijklmnopqrstuvwxyz") =
   32D10C7B8CF96570CA04CE37F2A19D84240D3A89

The output matches the testing result listed in FreeBSD libmd makefile: http://www.opensource.apple.com/source/libmd/libmd-2/Makefile.

Table of Contents

 About This Book

 Cryptography Terminology

 Cryptography Basic Concepts

 Introduction to AES (Advanced Encryption Standard)

 Introduction to DES Algorithm

 DES Algorithm - Illustrated with Java Programs

 DES Algorithm Java Implementation

 DES Algorithm - Java Implementation in JDK JCE

 DES Encryption Operation Modes

 DES in Stream Cipher Modes

 PHP Implementation of DES - mcrypt

 Blowfish - 8-Byte Block Cipher

 Secret Key Generation and Management

 Cipher - Secret Key Encryption and Decryption

 Introduction of RSA Algorithm

 RSA Implementation using java.math.BigInteger Class

 Introduction of DSA (Digital Signature Algorithm)

 Java Default Implementation of DSA

 Private key and Public Key Pair Generation

 PKCS#8/X.509 Private/Public Encoding Standards

 Cipher - Public Key Encryption and Decryption

 MD5 Mesasge Digest Algorithm

SHA1 Mesasge Digest Algorithm

 What Is SHA1 Message Digest Algorithm?

 SHA1 Message Digest Algorithm Overview

Using SHA1 Message Digest in Java

 Using SHA1 Message Digest in PHP

 Using SHA1 Message Digest in Perl

 OpenSSL Introduction and Installation

 OpenSSL Generating and Managing RSA Keys

 OpenSSL Managing Certificates

 OpenSSL Generating and Signing CSR

 OpenSSL Validating Certificate Path

 "keytool" and "keystore" from JDK

 "OpenSSL" Signing CSR Generated by "keytool"

 Migrating Keys from "keystore" to "OpenSSL" Key Files

 Certificate X.509 Standard and DER/PEM Formats

 Migrating Keys from "OpenSSL" Key Files to "keystore"

 Using Certificates in IE

 Using Certificates in Google Chrome

 Using Certificates in Firefox

 Archived Tutorials

 References

 Full Version in PDF/EPUB