Update User Guide and Dev Guide for encryption

docs/DeveloperGuide.adoc

@@ -439,7 +439,9 @@ The storage file "PlanMySem.txt" is encrypted to prevent easy access of the user
 We are encrypting and decrypting the data using the Java Cypher class.
 This feature is implemented through creating a Encryptor that contains encrypt and decrypt methods. The encrypt method takes a String object as an argument and returns a encrypted String object. The decrypt method takes in a String object as an argument and returns the decrypted message as a String object.
 
-Currently, the encryption is done using AES/ECB/PKCS5Padding. The key used for encryption is a placeholder key and the encrption mode is Electronic Codebook(ECB). In future updates, the key will be generated uniquely and Cipher Block Chaining(CBC) with a Initialization Vector(IV) will be used instead to improve security.
+The encryption is done using AES/CBC/PKCS5Padding. The key used for encryption/decryption is generated randomly and stored in a file named "KeyStorage.jceks". No password is required from the user to retrieve this key, but a password input can be added in the KeyStorage.java class to improve security. +
+
+A initialization vector (IV) is required for the Cipher Block Chain (CBC) mode of encryption. A random IV is generated and appended at the beginning of the data before being stored. The IV is then retrieved from the same file to decrypt the data.
 
 Encryption of the data is done automatically before the file is saved. In the implmentation, the AdaptedPlanner object is first marshalled into a StringWriter before being encrypted and written into the file. This is to ensure that the data is JAXB formatted and the save algorithm is unaffected.
 Similarly, decryption of the data is done automatically before it is loaded. In the implementation, the file is read and decrypted and parsed into a StringReader object. The StringReader object is then unmarshalled and loaded. This is to ensure that the file is converted back into a JAXB object before being loaded and the load algorithm is unaffected.