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Object Automation library
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package com.viaoa.util;

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.*;

import javax.crypto.*;
import javax.crypto.spec.DESKeySpec;

/*
    Sun:
    http://java.sun.com/javase/6/docs/technotes/guides/security/crypto/CryptoSpec.html    

    Sample programs:
    http://www.owasp.org/index.php/Digital_Signature_Implementation_in_Java
    http://www.rgagnon.com/javadetails/java-0400.html    

*/

public class OAEncryption {

    /**
     * Generates a SHA-256 hash code base64 string for a given input.
     * This is a one way function (irreversible).
     * 
     * Example: used when the real password is not stored.  Instead
     * the hash is stored and is used to compare the hash of user input.
     */
    public static String getSHAHash(String input){
        return getHash(input);
    }
    public static String getHash(String input){
        if (input == null) return null;
        MessageDigest md = null;
        
        try {
            md = MessageDigest.getInstance("SHA-256");
        }
        catch(NoSuchAlgorithmException e){
            System.out.println("No SHA-256");
            return null;
        }
        try {
          md.update(input.getBytes("UTF-8"));
        }
        catch(UnsupportedEncodingException e)
        {
            System.out.println("Encoding error.");
        }
        
        byte raw[] = md.digest();
        String hash = new String(Base64.encode(raw));
        
        return hash;
    }

    
    /**
     * Encrypt bytes into a new byte array.
     * @see #decrypt(byte[])
     */
    public static byte[] encrypt(byte[] bs) throws Exception {
        Cipher cipher = Cipher.getInstance("DES");
        cipher.init(Cipher.ENCRYPT_MODE, getSecretKey());
        
        bs = cipher.doFinal(bs);
        return bs;
    }
    public static byte[] encrypt(byte[] bs, String password) throws Exception {
        Cipher cipher = Cipher.getInstance("DES");
        
        SecretKey key;
        if (OAString.isEmpty(password)) key = getSecretKey();
        else key = getSecretKey(password);
        
        cipher.init(Cipher.ENCRYPT_MODE, key);
        
        bs = cipher.doFinal(bs);
        return bs;
    }

    public static Cipher getCipher() throws Exception {
        Cipher cipher = Cipher.getInstance("DES");
        cipher.init(Cipher.ENCRYPT_MODE, getSecretKey());
        return cipher;
    }
    
    /**
     * Decrypt bytes into a new byte array.
     * @see #encrypt(byte[])
     */
    public static byte[] decrypt(byte[] bs) throws Exception {
        Cipher cipher = Cipher.getInstance("DES");
        cipher.init(Cipher.DECRYPT_MODE, getSecretKey());
        bs = cipher.doFinal(bs);
        return bs;
    }
    public static byte[] decrypt(byte[] bs, String password) throws Exception {
        Cipher cipher = Cipher.getInstance("DES");

        SecretKey key;
        if (OAString.isEmpty(password)) key = getSecretKey();
        else key = getSecretKey(password);

        cipher.init(Cipher.DECRYPT_MODE, key);
        bs = cipher.doFinal(bs);
        return bs;
    }

    private static SecretKey _secretKey;
    /**
     * DES secret key used for encrypting data.
     */
    public static SecretKey getSecretKey() throws Exception {
        if (_secretKey == null) {
            byte[] bs = new byte[DESKeySpec.DES_KEY_LEN];
            for (int i=0; i \""+s2+"\"");

        
        String s3 = decrypt(s2, "password");
        System.out.println("Decrypted ==> \""+s3+"\"");

        String s4 = getHash(s);
        System.out.println("Hashed ==> \""+s4+"\"");
    }
    
}