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package anlavn.hash;
// Make By Bình An || AnLaVN || KatoVN

import anlavn.file.Log;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**The MD5 class supports object and string encryption, decryption it is impossible.
 * MD5 uses the Message-Digest algorithm 5 cryptographic hash function with a 128-bit long hash value.
 * 
Make sure your object class was "implements Serializable".
 * @author AnLaVN - https://github.com/AnLaVN
 * @deprecated The security of the MD5 hash function is severely compromised. 
 * A collision attack exists that can find collisions within seconds on a computer with a 2.6 GHz Pentium 4 processor 
 * (complexity of 2^24.1). Further, there is also a chosen-prefix collision attack that can produce a collision 
 * for two inputs with specified prefixes within seconds, using off-the-shelf computing hardware (complexity 2³⁹).
 */
@Deprecated
public class MD5 {
    
    private static String encrypt(final byte[] bytes){
        try {
            final MessageDigest md = MessageDigest.getInstance("MD5");
            final byte[] hash = md.digest(bytes);
            final BigInteger no = new BigInteger(1, hash);
            String hashtext = no.toString(16);
            while (hashtext.length() < 32) {
                hashtext = "0" + hashtext;
            }
            return hashtext;
        }catch (NoSuchAlgorithmException e) {
            Log.add("!!! Error try to Encrypt MD5. !!!\n\tError code: " + e.toString());
            return null;
        }
    }
    
    
    /**Use this method to encrypt the original object.
     * @param objToEncrypt is the object need encrypt.

     * @return a MD5 hash code of the original object.
     */
    public static final String encrypt(final Object objToEncrypt){
        try {
            final ByteArrayOutputStream bos = new ByteArrayOutputStream();
            final ObjectOutputStream oos = new ObjectOutputStream(bos);
            oos.writeObject(objToEncrypt); oos.flush();
            return encrypt(bos.toByteArray());
        }catch (IOException e) {
            Log.add("!!! Error try to Encrypt MD5 an Object. Can not parse Object to bytes. !!!\n\tError code: " + e.toString());
            return null;
        }
    }
    
    
    /**Use this method to encrypt the original string.
     * @param strToEncrypt is the string need encrypt.

     * @return a MD5 hash code of the original string.
     */
    public static final String encrypt(final String strToEncrypt){
        return encrypt(strToEncrypt.getBytes());
    }
}