com.baran.crypto.CryptoDES.java Source code

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Here is the source code for com.baran.crypto.CryptoDES.java

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/* 
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
 * Company: -                                               *            
 * Assignment: Cyclic Redundancy Check + DES + Hibernate + JAX-WSRPC    *
 * Deadline: -                                                     *
 * Programmer: Baran Topal                                         *
 * WorkspaceName: Crypto                                      *
 * Project Name: CyrptoPro                                        *
 * Package name: com.baran.crypto                                *
 * File name: CryptoDES.java                                       *
 *                                                                 *      
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *                                                                                            *
 *  LICENSE: This source file is subject to have the protection of GNU General               *
 *   Public License. You can distribute the code freely but storing this license information. *
 *   Contact Baran Topal if you have any questions. barantopal@barantopal.com                 *
 *                                                                                            *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 */

package com.baran.crypto;

import java.io.File;
import java.security.MessageDigest;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.io.FileUtils;

// Important Note:
// The file in question must have UTF-8 encoding, careful about BOM character.

public class CryptoDES {

    // encrypt the file content via trivia password
    public byte[] encrypt(File file, String trivia) throws Exception {
        final MessageDigest md = MessageDigest.getInstance("md5");
        // digest the trivia password in UTF-8
        final byte[] digestTrivia = md.digest(trivia.getBytes("utf-8"));

        // truncating digest
        final byte[] keyBytes = Arrays.copyOf(digestTrivia, 24);
        for (int j = 0, k = 16; j < 8;) {
            keyBytes[k++] = keyBytes[j++];
        }
        // DESede setting
        final SecretKey key = new SecretKeySpec(keyBytes, "DESede");

        // CBC IV setting
        final IvParameterSpec iv = new IvParameterSpec(new byte[8]);

        final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key, iv);

        String allInOne = FileUtils.readFileToString(file, "utf-8");

        final byte[] plainTextBytes = allInOne.getBytes("utf-8");
        final byte[] cipherText = cipher.doFinal(plainTextBytes);

        return cipherText;
    }

    // decrypt the message via trivia password
    public byte[] decrypt(byte[] message, String trivia) throws Exception {
        final MessageDigest md = MessageDigest.getInstance("md5");
        final byte[] digestTrivia = md.digest(trivia.getBytes("utf-8"));

        final byte[] keyBytes = Arrays.copyOf(digestTrivia, 24);

        for (int j = 0, k = 16; j < 8;) {
            keyBytes[k++] = keyBytes[j++];
        }

        final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
        final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
        final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
        decipher.init(Cipher.DECRYPT_MODE, key, iv);

        final byte[] plainText = decipher.doFinal(message);

        return plainText;
    }
}