eu.clarussecure.dataoperations.splitting.SymmetricCrypto Maven / Gradle / Ivy

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CLARUS Splitting Module
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package eu.clarussecure.dataoperations.splitting;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

public class SymmetricCrypto {

    public static final String KEY = "." + File.separator + "keys" + File.separator + "AES.key";

    public static byte[] encrypt(String text, String key)
            throws FileNotFoundException, IOException, ClassNotFoundException {
        return encrypt(text.getBytes(), key);
    }

    public static byte[] encrypt(byte[] text, String key)
            throws FileNotFoundException, IOException, ClassNotFoundException {
        ObjectInputStream keyStream = new ObjectInputStream(new FileInputStream(key));
        final SecretKey publicKey = (SecretKey) keyStream.readObject(); // la
                                                                        // key
                                                                        // no ha
                                                                        // de
                                                                        // canviar
                                                                        // per a
                                                                        // res,
                                                                        // aixi
                                                                        // que
                                                                        // la
                                                                        // definim
                                                                        // com a
                                                                        // final
        keyStream.close();
        return encrypt(text, publicKey);
    }

    public static byte[] encrypt(byte[] text, SecretKey key) {
        byte[] cipherText = null;

        try {
            final Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            cipherText = cipher.doFinal(text);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return cipherText;
    }

    public static byte[] decrypt(String text, String key)
            throws FileNotFoundException, IOException, ClassNotFoundException {
        return decrypt(text.getBytes(), key);
    }

    public static byte[] decrypt(byte[] text, String key)
            throws FileNotFoundException, IOException, ClassNotFoundException {
        ObjectInputStream keyStream = new ObjectInputStream(new FileInputStream(key));
        final SecretKey publicKey = (SecretKey) keyStream.readObject();
        keyStream.close();
        return decrypt(text, publicKey);
    }

    public static byte[] decrypt(byte[] text, SecretKey key) {
        byte[] dectyptedText = null;
        try {
            final Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, key);
            dectyptedText = cipher.doFinal(text);
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return dectyptedText;
    }

    public static void generateKey() {
        try {
            final KeyGenerator keyGen = KeyGenerator.getInstance("AES");
            keyGen.init(128);
            final SecretKey key = keyGen.generateKey();

            File keyFile = new File(KEY);

            // Create files to store public and private key
            if (keyFile.getParentFile() != null) {
                keyFile.getParentFile().mkdirs();
            }
            keyFile.createNewFile();

            // Saving the Private key in a file
            ObjectOutputStream keyOS = new ObjectOutputStream(new FileOutputStream(keyFile));

            keyOS.writeObject(key);
            keyOS.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}