Week 1. This week's topic is an overview of what cryptography is about as well as our first example ciphers. You will learn about pseudo-randomness and how to use it for encryption. We will also look at a few basic definitions of secure encryption.

Week 2. We introduce a new primitive called a block cipher that will let us build more powerful forms of encryption. We will look at a few classic block-cipher constructions (AES and 3DES) and see how to use them for encryption. Block ciphers are the work horse of cryptography and have many applications. Next week we will see how to use block ciphers to provide data integrity. The optional programming assignment this week asks students to build an encryption/decryption system using AES.

Week 3. This week's topic is data integrity. We will discuss a number of classic constructions for MAC systems that are used to ensure data integrity. For now we only discuss how to prevent modification of non-secret data. Next week we will come back to encryption and show how to provide both confidentiality and integrity. This week's programming project shows how to authenticate large video files. Even if you don't do the project, please read the project description --- it teaches an important concept called a hash chain.

Week 4. This week's topic is authenticated encryption: encryption methods that ensure both confidentiality and integrity. We will also discuss a few odds and ends such as how to search on encrypted data. This is our last week studying symmetric encryption. Next week we start with key management and public-key cryptography. As usual there is also an extra credit programming project. This week's project involves a bit of networking to experiment with a chosen ciphertext attack on a toy web site.