Coder.java

package net.lordgatto.Functions;

import java.util.Base64;
import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.*;
import java.security.spec.*;

public class Coder {
    private static final int KEY_SIZE = 256;
    private static final int IV_SIZE = 16;
    private static final int SALT_SIZE = 16;
    private static final int ITERATIONS = 65536;

    public static byte[] generateRandomBytes(int lenght) {
        byte[] bytes = new byte[lenght];
        new SecureRandom().nextBytes(bytes);
        return bytes;
    }

    public static SecretKeySpec deriveKeyFromPassword(String password, byte[] salt) throws Exception {
        SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
        KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, ITERATIONS, KEY_SIZE);
        byte[] KeyBytes = factory.generateSecret(spec).getEncoded();
        return new SecretKeySpec(KeyBytes, "AES");
    }

    public static byte[] encrypt(String text, String password) throws Exception {
        byte[] salt = generateRandomBytes(SALT_SIZE);
        byte[] iv = generateRandomBytes(IV_SIZE);

        SecretKeySpec key = deriveKeyFromPassword(password, salt);

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(iv));
        byte[] encrypted = cipher.doFinal(text.getBytes());

        byte[] combined = new byte[salt.length + iv.length + encrypted.length];
        System.arraycopy(salt, 0, combined, 0, salt.length);
        System.arraycopy(iv, 0, combined, salt.length, iv.length);
        System.arraycopy(encrypted, 0, combined, salt.length + iv.length, encrypted.length);

        return combined;
    }

    public static String decrypt(byte[] text, String password) throws Exception {
        byte[] salt = new byte[SALT_SIZE];
        byte[] iv = new byte[IV_SIZE];
        byte[] ciphed = new byte[text.length - ( SALT_SIZE + IV_SIZE )];

        System.arraycopy(text, 0, salt, 0, SALT_SIZE);
        System.arraycopy(text, SALT_SIZE, iv, 0, IV_SIZE);
        System.arraycopy(text, SALT_SIZE + IV_SIZE, ciphed, 0, ciphed.length);

        SecretKeySpec key = deriveKeyFromPassword(password, salt);

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));
        byte[] decrypted = cipher.doFinal(ciphed);

        return new String(decrypted);
    }

    public static String Code(String decoded) {
        return Base64.getEncoder().encodeToString(decoded.getBytes());
    }

    public static String Decode(String encoded) {
        return new String(Base64.getDecoder().decode(encoded));
    }
}