Binary file encryption and decryption (AES) (Java)

aes

public static void encryptFile(SecretKeySpec key, IvParameterSpec iv, String inputFilePath, String outputFilePath) {
    try {
        Cipher encryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        encryptCipher.init(Cipher.ENCRYPT_MODE, key, iv);

        File inFile = new File(inputFilePath);
        File outFile = new File(outputFilePath);

        Files.touch(outFile);

        InputStream is = new FileInputStream(inFile);
        OutputStream os = new FileOutputStream(outFile);
        CipherOutputStream cos = new CipherOutputStream(os, encryptCipher);

        byte[] buffer = new byte[1024];

        int length;

        while ((length = is.read(buffer)) > 0) {
            cos.write(buffer, 0, length);
        }

        is.close();
        cos.flush();
        cos.close();
    }
    catch (Exception e) {
        // log exception
    }
}

public static void decryptFile(SecretKeySpec key, IvParameterSpec iv, String inputFilePath, String outputFilePath) {
    try {
        Cipher encryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        encryptCipher.init(Cipher.DECRYPT_MODE, key, iv);

        File inFile = new File(inputFilePath);
        File outFile = new File(outputFilePath);

        Files.touch(outFile);

        InputStream is = new FileInputStream(inFile);
        OutputStream os = new FileOutputStream(outFile);
        CipherInputStream cis = new CipherInputStream(is, encryptCipher);

        byte[] buffer = new byte[1024];

        int length;

        while ((length = cis.read(buffer)) > 0) {
            os.write(buffer, 0, length);
        }

        cis.close();
        os.flush();
        os.close();
    }
    catch (Exception e) {
        // log exception
    }
}

It is not working for me...