Cryptography: From Theory to Practice

You use cryptography every time you make a credit card-based Internet purchase or use an ATM machine. But what is it? How does it work and how do we know when it is secure? This talk is an introduction to the problems, issues, colorful personalities and advances in this area. We will explain how cryptography is a marriage of mathematics and computer science. We will explain what are proofs of security and their value and limitations in providing security assurance. We will see how gaps between theory and practice are rooted in the culture of the field and how they have been lifted to the point where proven secure schemes are present in Microsoft products. We will present case studies that explain the theory and origins of some cryptographic schemes now in use. We will then discuss some future directions.