Srimathi Varadharajan successfully completed her PhD trial lecture and thesis defense at the University of Bergen, on the 22nd November 2019 and on the 28th of April 2020, respectively, and will be awarded the degree of Doctor of Philosophy.
The title of her thesis is “Hard Mathematical Problems in Cryptography and Coding Theory” and the topic of her trail lecture was: “Fermat’s last theorem”.
Cryptography and code theory are two important fields of communication exchange. Code theory is about how information can be represented in a way that makes it possible to automatically correct errors that occur during shipping. Cryptography deals with techniques to keep information secret and to ensure that information has not been changed between sender and recipient. Both fields are based on difficult mathematical problems.
Srimathi’s dissertation deals with a variety of such problems and studies possible algorithms to solve them. One example of such a problem is the factoring of large numbers into their prime factors, which form the basis for much of the security of the Internet today. Another example is the problem of finding the shortest vector in a so-called lattice. It is known that a quantum computer can effectively solve the factorization problem, while it is believed that it is not possible to effectively solve the shortest-vector problem, even with a quantum computer. Lattice-based cryptography is therefore a good candidate for securing the Internet of the future, and it is important to understand how difficult this problem is and what makes it difficult.
Srimathi Varadharajan carried out her PhD work at the Department of Informatics, University of Bergen.
Her main supervisor was Håvard Raddum, Simula.