Public Key Cryptography Basics: RSA, Diffie-Hellman, SSH, and Certificates in Practice

The official room banner for Public Key Cryptography Basics. Image Credit: TryHackMe.

Introduction

Welcome back to my walkthrough series on the Cryptography module of the Cyber Security 101 path! This time we’re tackling Public Key Cryptography Basics, the second of the module’s four introductory rooms.

In my previous article, Cryptography Basics, we covered the core vocabulary of encryption — plaintext, ciphertext, ciphers, and keys — worked through the historical Caesar Cipher, and got comfortable with the XOR and modulo operations that show up throughout cryptography. This room builds directly on that foundation, moving from the theory of symmetric versus asymmetric encryption into the real protocols and tools that put asymmetric cryptography to work: RSA, Diffie-Hellman, SSH keys, TLS certificates, and PGP/GPG.

Catch up on my previous article, Cryptography Basics, by clicking the banner below.

The official room banner for Cryptography Basics. Image Credit: TryHackMe.

What we will cover

• Why asymmetric cryptography matters, illustrated with a simple lock-and-key analogy
• The math behind RSA, and a worked numerical example