CST311 - week 4

 

CST311 – Intro to Computer Networks 

We are halfway into this course, and the focus is on network security this week. As usual, the subject of network security covers a variety of fundamental concepts related to data security transmission and safe storage. Securing data communication aims to maintain confidentiality, data integrity, availability, and authentication. Several cryptographic techniques are used to achieve confidentiality by encrypting the transmitted message, making it impossible for the interceptor to decode it. The reliable transport and data link protocol is used for message integrity to ensure senders and recipients are communicating with each other with confidence. Message authentication codes (MACs) and digital signatures are two distinct methods that provide message integrity.

At a high level, the idea of cryptography is to mask the sender's original message to a recipient and reserve a method for the intended receiver(s) to recover the data. For example, a sender uses an encryption algorithm on a raw message called plaintext to produce ciphertext. On the other hand, a receiver will use decryption algorithm to recover the plaintext. One of the oldest techniques is the use of a symmetric key to encrypt and decrypt. However, sharing such a key poses logistics and even more security risk among participants. A public key partially solves these challenges by allowing senders to freely encrypt the message. A private key is only known to the recipients and must allow the decryption of the message. The RSA algorithm is a widely used public-key cryptographic algorithm, a mathematical concept built on modulus. Additionally, Cryptographic hash function and digital signatures secure email communication by authenticating users and warranting integrity.