Sophia Yakoubov

Project title

YOSO: Efficient "You Only Speak Once" Secure Computation

What is your project about?

As data breaches become more common, companies have transferred many digital tasks to decentralised platforms - such as data clouds and blockchains - to eliminate single points of failure. However, distributed systems are still susceptible to attacks by sophisticated adversaries who can target multiple machines in a system at once. The You Only Speak Once (YOSO) framework is a novel paradigm for large-scale secure distributed processing of private data. In a YOSO protocol, each machine sends at most one message; by hiding who will send future messages, YOSO protocols can achieve unprecedented asymptotic communication efficiency while protecting the data from the most powerful kind of adversary. Existing YOSO protocols only provide security under unrealistic conditions, or do not scale well. The goal of this project is to eliminate these drawbacks, bringing YOSO closer to practice.

How did you become interested in your particular field of research?

I have always loved logic puzzles and mathematical thinking. As a child, I explored secret codes such as the Caeser and Vigenere ciphers, and would use them to scramble messages to my friends. During my undergraduate studies I took my first formal classes in cryptography, and really enjoyed learning about applications of discrete mathematics to real security problems. This led me to get a job as a security researcher when I graduated, and eventually to pursue a PhD in cryptography.

What are the scientific challenges and perspectives in your project?

Much of this project focuses on theoretical questions, such as designing protocols with better asymptotic efficiency and establishing lower bounds. There is no formula to follow in pursuit of either goal; it is hard to predict what will be possible. However, achieving these goals - and thus better understanding the landscape of YOSO possibilities and impossibilities - is an important step towards advancing the state of the art in secure distributed computation.

What is your estimate of the impact, which your project may have to society in the long term?

I hope that this project will help make secure and efficient computation in large-scale distributed environments such as clouds and blockchains more feasible. This, in turn, might have applications in many scenarios where mutually distrusting parties wish to outsource a computation on their sensitive data. An example might be hospitals in different countries wishing to pool their medical records for use in medical research, without compromising their patients' privacy by revealing those records to any external parties.

Which impact do you expect the Sapere Aude programme will have on your career as a researcher?

Receiving the Sapere Aude grant will allow me to establish my own research team, and to grow as a supervisor and a leader. It will also allow me to strengthen my international collaborations and relationships through travel and research visits.

Background and personal life

I am an American ex-pat living in Denmark. I initially came to Aarhus University as a visiting PhD student in 2019, with the intention of staying for three months. However, I ended up loving my collaborators and the vibrant small-city life here so much that I'm still around, almost four years later. I'm a vegan animal-lover, and in my spare time I make fumbling attempts to learn tennis, and occasionally dabble in creative writing.