This course focuses on Domain 4 of the CISSP exam, covering network security. It begins with an in-depth look at the OSI Reference Model. At each layer, we will discuss functionality, threats/vulnerabilities and common mitigation strategies. In addition, we will focus on firewalls, proxy servers and remote access solutions. It also covers the security services that cryptography can provide and examine common terms like initialization vectors, salts, hashing, algorithms and keys. We will then build on this foundation to explore symmetric, asymmetric and hybrid cryptography and look at its practical implementations.