Lab $4$ Tasks

You will implement a "Caesar" object, which is an object that can perform encryption and decryption in our modified Caesar Cipher operation.

This Caesar object should have exactly one field: an integer representing the key to the cipher. This field should be private and you should have a corresponding getter and setter.

The class does not need to include a constructor. If you choose to include any, make sure the default constructor is callable.

You must implement an 'encrypt' method, which performs encryption based on the modified Caesar Cipher described above with the following signature:

public String encrypt$($String plaintext$)$

plaintext is the message to be encrypted

The method should return the ciphertext, encrypted using this object's key

You must implement an 'decrypt' method, which performs decryption based on the modified Caesar Cipher described above.

public String decrypt$($String ciphertext$)$

ciphertext is the encrypted message to be decrypted

The method should return the plaintext message, decrypted with this object's key

You are encouraged to write a main method to test your two methods but your main method will not be tested by the AutoTester.

Example main method with output

public static void main$($String$[$ argos$)$

$\{$

Caesar cipher $=$ new Caesar$()$;

cipher.setKey$(3)$;

System.out.printIn$($cipher$.$encrypt$("$hello WORLD!"$))$; $//$ prints "KHOOR zruog!"

System.out.printIn$($cipher$.$decrypt$($KHOOR zruog!"$))$; $//$prints "hello WORLD!$$