In this talk we will discuss the use of Steganography (hiding the fact that two parties are communicating, or hiding a secret message within an innocuous one) for tracing software pirates. Watermarking represents a particular use of steganography where the hidden message is a copyright notice or a customer identification number, and the innocuous (cover) message is a digital image, an audio file, or a video clip. For example, inside a song file downloaded from iTunes may be hidden the credit card number of the customer, allowing the copyright owner to trace a pirated copy of a song back to the person who originally purchased it. Watermarking doesn't prevent illegal copying of media, but rather allows the tracing of pirates after the fact. In this talk we will discuss the watermarking of software. That is, we are interested in embedding a secret mark inside a computer program to allow us to trace software pirates. We will see how several watermark embedding algorithms have been designed based on graph problems such as graph coloring and graph enumerations.

When information is transmitted over a noisy communication channel, errors may be introduced. Detecting and correcting the errors require adding redundancy to the information sent which in turn increases the cost of transmitting the information. Coding theory searches for efficient methods to achieve error-correction without increasing the cost too much. The applications are endless: wireless communication, CD recording, data transmission from spacecrafts, packet transmission over the Internet, data transfer through modem, ... In this talk, we will work through examples of error-detection and error-correction methods. We will then provide the ultimate limit on how good a code can be: the Shannon bound.

About Cliff Stoll’s (Ph.D., University of Arizona, 1980) pursuit and capture of a German hacker who stole information from US military computers over the internet.

Cryptography (secret writing) has an intriguing history, and forms part of the history of intrigue. It has always also had a business application, since business people have wanted to keep secrets from their competitors. More recently it has entered the world of business in a more mundane way, because of public key cryptography, which allows businesses, banks, and credit card companies to broadcast to the world the key by which consumers can send them secret messages to transfer money or charge a credit card. How is it possible for them to do this without also giving away the secret to decoding those secret instructions? In this talk we will survey the history of cryptography and outline the principles of public key cryptography. The talk is intended to be intelligible to the general public.

A few decades ago (fortunately, just in time for the Information Age) it was discovered that it is possible for two people who have never met to communicate with one another in a way that is secure against eavesdropping. It is remarkable that this is possible in the absence of shared private information, such as the key to a classical cryptosystem. The security of these so-called public-key protocols lies in the computational infeasibility of finding the key, rather than in secrecy. The number theoretic ideas used by these protocols were first discovered hundreds of years ago by pure mathematicians, but have become one of the most important areas of active research in applied mathematics. In this talk we'll describe public-key cryptography via the RSA algorithm, which can be applied to both secure communication and identity verification.