/**
 * This file is part of Graylog.
 *
 * Graylog is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Graylog is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Graylog.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.graylog2.security;

import org.apache.shiro.codec.Hex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nullable;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class AESTools {
    private static final Logger LOG = LoggerFactory.getLogger(AESTools.class);

    @Nullable
    public static String encrypt(String plainText, String encryptionKey, String salt) {
        try {
            @SuppressWarnings("CIPHER_INTEGRITY")
            Cipher cipher = Cipher.getInstance("AES/CBC/ISO10126Padding", "SunJCE");
            SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
            cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(salt.getBytes("UTF-8")));
            return Hex.encodeToString(cipher.doFinal(plainText.getBytes("UTF-8")));
        } catch (Exception e) {
            LOG.error("Could not encrypt value.", e);
        }
        return null;
    }

    @Nullable
    public static String decrypt(String cipherText, String encryptionKey, String salt) {
        try {
            @SuppressWarnings("CIPHER_INTEGRITY")
            Cipher cipher = Cipher.getInstance("AES/CBC/ISO10126Padding", "SunJCE");
            SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
            cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(salt.getBytes("UTF-8")));
            return new String(cipher.doFinal(Hex.decode(cipherText)), "UTF-8");
        } catch (Exception e) {
            LOG.error("Could not decrypt value.", e);
        }
        return null;
    }
}