Sophie Stevens, a mathematics undergraduate, is co-author on the paper, ‘Key-Homomorphic Constrained Pseudorandom Functions’, with colleagues from Georgia Tech University in USA and the Institute of Science and Technology (IST) in Austria. Sophie contributed to the paper during a summer internship at IST, under the supervision of Krzysztof Pietrzak. The paper has other connections to Bristol since another co-author Georg Fuchsbauer is a former member of staff from the University’s Department of Computer Science.

The paper presents constructions of a family of functions, indexed by a key, which look like they produce random outputs, but for which one can “add” the keys to two functions to obtain another function in the family.  The constructions are mainly based on an old area of mathematics arising from the geometry of numbers. Recent years have seen an increasing number of applications of such functions to construct cryptographic schemes with special properties.

Sophie Stevens said: “It is really exciting to be involved in research as an undergraduate.  This work has helped me make up my mind to continue my studies at Bristol next year as a mathematics PhD student.”

Professor Nigel Smart, Head of the Cryptography group, added: “It is no mean feat to have a paper accepted at the TCC conference. Many cryptographers, including myself, have never had a paper at this conference. For Sophie to accomplish this at such a young age shows she has a glittering career in front of her.”

Dr Lynne Walling, Head of Pure Mathematics, commented: “The fact that Sophie can contribute to a paper that has been accepted at one of the top cryptography conferences is a testament not only to Sophie’s talents, but also the excellent teaching and learning environment provided by the School of Mathematics.”