Implementation of E2EE Using Python

Abstract

The need for cyber security is felt now more than ever. In an era of constant mass surveillance, illegal spying and cyber-attacks, it is extremely important to have a secure means of communication which cannot be intercepted. Several new protocols were introduced such as HTTPS to encrypt the connection between the client and the server. This made sure that no third person can read the data being transmitted to and from the client. This model of encryption had one major flaw: the server itself. Every message that was encrypted by the sender was decrypted at the server, encrypted again and sent to the receiver. Thus the server can read all the messages. The users of such chatting services had to trust the owners of the services with their privacy. Even if the owners were not involved in shady data deals, they still had the risk of their servers getting hacked or being pressured by the government to reveal the data of their users. All these issues paved the way for a new type of implementation of encryption known as end-to-end encryption often abbreviated as E2EE. The message to be sent is encrypted by the sender and is sent to the server which relays it to the receiver as it is. Since the keys used to encrypt and decrypt the data are available only to the users, the server cannot read the messages sent through it. This model quickly gained popularity and was implemented by many messaging applications, the most notable being WhatsApp, Signal, Telegram, and Wire. In this project, we are going to implement E2EE using Python. For encryption, we intend to use the AES algorithm. AES stands for advanced encryption standard which was introduced in 2001 by the NITS (U.S.A.). It was developed by Vincent Rijmen and Joan Daemen in response to the earlier broken algorithm DES. AES is a symmetric key encryption algorithm meaning that the same key is used for encryption as well as decryption of the messages. This algorithm has three key lengths—128,192 and 256 bits, whereas a single block size of 128 bits. The version we are going to implement is 128 bits key size.