CODEWITHSUNDEEP
javaencryptionjava-8
William
William

Reputation: 241

Reading an Encrypt file

I am writing an application that encrypts a list of Employee into a text file. I was able to encrypt the Employees list to a text file. When I try to decrypt it back, I am getting some error saying

java.lang.ClassCastException: com.reading.employee.blueprint.Employee cannot be cast to java.base/java.util.List

This is an example of the code I am working on. 

private static byte[] encryptingAFile(List<Employee> list) {
    byte[] empList, textEncrypted = null;

    try {
        ByteArrayOutputStream byteArray = new ByteArrayOutputStream();
        ObjectOutputStream object = new ObjectOutputStream(byteArray);

        KeyGenerator keygenerator = KeyGenerator.getInstance("AES");
        SecretKey myDesKey = keygenerator.generateKey();

        Cipher desCipher;
        desCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        String s;

        for (Employee employee: list) {
            object.writeObject(employee);
        }

        empList = byteArray.toByteArray();
        desCipher.init(Cipher.ENCRYPT_MODE, myDesKey, new IvParameterSpec(new byte[16]));
        textEncrypted = desCipher.doFinal(empList);

        Files.write(Paths.get("Encrypt.txt"), textEncrypted);

        desCipher.init(Cipher.DECRYPT_MODE, myDesKey, new IvParameterSpec(new byte[16]));
        byte[] textDecrypted = desCipher.doFinal(textEncrypted);

        ByteArrayInputStream bis = new ByteArrayInputStream(textDecrypted);
        ObjectInputStream ois = new ObjectInputStream(bis);
        List<Employee > result = (List<Employee>) ois.readObject();

        System.out.println(result.toString());

    }
    catch (InvalidKeyException in) {
        System.out.println(in);
    }
    catch (Exception e) {
        System.out.println(e);
    }
    return textEncrypted;
}

I was hoping that someone could help me.

Upvotes: 1

Views: 38

Answers (1)

Daniel Pryden
Daniel Pryden

Reputation: 60987

When you write the objects to the ObjectOutputStream, you write each Employee one at a time, you don't write a single list object. So when you read them back in, you don't get a single list object back. Either you need to write the whole list to the stream in the first place, or you need to read the Employee objects back one at a time.

Upvotes: 2

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