Network Security, Threats, Authentication, Authorization, and Securing Devices

Nowadays, almost all the information is stored electronically in computers, network servers, mobile devices, or other storage media. We cannot protect electronic information in a cabinet in the same way we protected physical documents in the past. We have to come up with new techniques to protect the information from unauthorized access, use, or manipulation. The easiest way to protect electronic data is to encrypt it so that people cannot gure out what it contains without knowing the secret keys. Over the last several decades, two major types of encryption techniques have been invented: private key encryption and public key encryption.