Cryptography Basics

The main goal of cryptography is the design of protocols for encryption that enables secure communication over an insecure channel in the presence of possibly malicious adversaries. These protocols play a vital role in information security, as we’ll show in this lesson. In particular, they have to provide the following properties:

• Confidentiality: The information isn’t available for unauthorized parties.
• Authentication: It’s possible to verify the origin of a message.
• Integrity: It’s provable that the contents of a message have not been changed since the message was sent.
• Non-repudiation: The sender of a message cannot deny that they sent the message.