Basic Cryptography and Programming with Crypto API

Overview

Class Central Tips

In this MOOC, we will learn the basic concepts and principles of crytography, apply basic cryptoanalysis to decrypt messages encrypted with mono-alphabetic substitution cipher, and discuss the strongest encryption technique of the one-time-pad and related quantum key distribution systems. We will also learn the efficient symmetric key cryptography algorithms for encrypting data, discuss the DES and AES standards, study the criteria for selecting AES standard, present the block cipher operating modes and discuss how they can prevent and detect the block swapping attacks, and examine how to defend against replay attacks. We will learn the Diffie-Hellman Symmetric Key Exchange Protocol to generate a symmetric key for two parties to communicate over insecure channel. We will learn the modular arithmetic and the Euler Totient Theorem to appreciate the RSA Asymmetric Crypto Algorithm, and use OpenSSL utility to realize the basic operations of RSA Crypto Algorithm. Armed with these knowledge, we learn how to use PHP Crypto API to write secure programs for encrypting and decrypting documents and for signing and verify documents. We then apply these techniques to enhance the registration process of a web site which ensures the account created is actually requested by the owner of the email account.

Syllabus

Basic Cryptography

In this module we learn the basic concepts and principles of crytography, introduce the basic concept of cryptoanalysis using mono-alphabetic substitution cipher as an example, and discuss the one-time-pad and quantum key distribution concepts.

Symmetric Key Cryptography

In this module we present the basic mechanism of symmetric key crytography algorithms, discuss the DES and AES standard, describe the criteria for selecting AES standard, present the block cipher operating modes and discuss how the block swapping attacks and replay attacks can be prevented and detected.

Asymmetric Key Cryptography

In this module we will learn the modular arithmetic, the Euler Totient Theorm, the RSA Asymmetric Crypto Algorithm, use OpenSSL to realize the basic operations of RSA Crypto Algorithm, and Diffie-Hellman Symmetric Key Exchange Protocol to derive session keys.

Develop Secure Programs with Crypto API

In this module, we learn how to use Crypto API to write secure programs for encrypting and decrypting documents, and for signing and verify documents. We then apply the techniques to enhance the registration process of a web site which ensures the account created is actually belonging to the owner of the email account the request profile.