## Speaker:

Prof. Alice Silverberg

## Institution:

Ohio State University

## Time:

Monday, February 2, 2004 - 3:00pm

## Location:

MSTB 254

Public key cryptography is about 25 years old, and relies on number theory. We will discuss Diffie Hellman key exchange and ElGamal encryption, and some recent improvements on them. We show how number theory and algebraic geometry, and in particular the rationality of certain algebraic tori, can be used to give a deeper understanding of these improvements, and to give new cryptosystems.