Simple encryption/decryption method packaging, including Encode (), decode (), MD5 ()

Simple encryption/decryption method packaging, including Encode (), decode (), MD5 ()
Publication date: 2004-07-30 author: [Reprint] Source:

Package Steeven;

/*
Purpose: Simple encryption/decryption method packaging
Author: steeven@kali.com.cn
Date: 12/05/2001
Thank you: http://www-900.ibm.com/developerWorks/java/l-security/index.shtml

Description
This Class need JCE, download here:
Http://java.sun.com/security/index.html

*/

Import java.security.*;
Import javax.crypto.*;
public class Crypt {

private static String algorithm= "DES"; Define cryptographic algorithms, available des,desede,blowfish

Static Boolean debug = FALSE;

static{
Security.addprovider (New Com.sun.crypto.provider.SunJCE ());
}

 //Generate key, note this step takes longer
  public static byte[] GetKey () throws exception{
    Keygenerator keygen = keygenerator.getinstance (algorithm);
    Secretkey Deskey = Keygen.generatekey ();
    if (debug)
      System.out.println ("Generate Key:" +byte2hex ( Deskey.getencoded ()));
    return deskey.getencoded ();
 }

 //encryption
  public static byte[] Encode (byte[] input,byte[] key) throws exception{
    Secretkey Deskey = new Javax.crypto.spec.SecretKeySpec (key,algorithm);
    if (debug) {
      System.out.println ("binary string Before encryption:" +byte2hex (input ));
      System.out.println ("String before Encryption:" +new string (input));
   }
    Cipher c1 = cipher.getinstance (algorithm);
    C1.init (Cipher.encrypt_mode,deskey);
    byte[] cipherbyte=c1.dofinal (input);
    if (debug)
      System.out.println ("Encrypted binary string:" +byte2hex ( Cipherbyte));
    return cipherbyte;
 }

 //decryption
  public static byte[] Decode (byte[] input,byte[] key) throws exception{
    Secretkey Deskey = new Javax.crypto.spec.SecretKeySpec (key,algorithm);
    if (debug)
      System.out.println ("Pre-decryption Information:" +byte2hex (input)) ;
    Cipher c1 = cipher.getinstance (algorithm);
    C1.init (Cipher.decrypt_mode,deskey);
    byte[] clearbyte=c1.dofinal (input);
    if (debug) {
      System.out.println ("Decrypted binary string:" +byte2hex ( Clearbyte));
      System.out.println ("decrypted string:" + (new string (Clearbyte));
   }
    return clearbyte;
 }

 //MD5 () information summary, irreversible
  public static byte[] MD5 (byte[] input) throws exception{
    Java . Security. MessageDigest alg=java.security.messagedigest.getinstance ("MD5"); or "SHA-1"
    if (debug) {
      System.out.println ("binary string before digest:" + Byte2hex (input));
      System.out.println ("String before Digest:" +new string (input));
   }
    alg.update (input);
    byte[] Digest = Alg.digest ();
    if (debug)
      System.out.println ("binary string after digest:" +byte2hex (Digest ));
    return digest;
 }

Byte code converted to 16 binary string
public static String Byte2hex (byte[] b) {
String hs= "";
String stmp= "";
for (int n=0;n stmp= (java.lang.Integer.toHexString (B[n] & 0XFF));
if (Stmp.length () ==1)
hs=hs+ "0" +STMP;
else hs=hs+stmp;
if (n}
return Hs.touppercase ();
}

public static void Main (string[] args) throws exception{
debug = true;
byte[] key = GetKey ();
byte[] key = "Study hard". GetBytes ();
Decode (Encode ("Test Encryption". GetBytes (), key), key);
MD5 ("Test Encryption". GetBytes ());
}
}