Data Science News

In a recent work, visiting undergraduate student Yahel Manor and Warwick DCS researchers Jinqiao Hu and Igor Oliveira addressed a fundamental question relevant to the security of cryptographic protocols.

The symmetry of information principle says that the amount of information that a sequence x of bits reveals about another sequence y is essentially the same in either direction. This is known to hold in an idealised world where computations can take an arbitrarily long time, as demonstrated by A. Kolmogorov and L. Levin in the 1970s. In contrast, modern cryptography is built around deliberate asymmetry—for example, functions of the form y = f(x) that are easy to compute but hard to invert (one-way functions).

The new work shows that, once one moves from the idealised setting of time-unbounded computations to the more realistic world of efficient, randomised computations (algorithms that must run quickly and may use randomness), this symmetry can fail in a strong and unconditional way. In other words, computational constraints can yield information asymmetry. In practical terms, this supports the intuition that information may not be extracted efficiently: knowing y = f(x) may not make x efficiently recoverable to the extent that an (ineffective) symmetry principle would suggest, even when x and y are closely related.

Earlier work formally tied an average-case form of this symmetry failure to the existence of one-way functions, the central primitive in cryptography. By proving new failures of symmetry of information, the authors provide concrete progress towards the computational asymmetry that underpins encryption, digital signatures, and many other cryptographic protocols.

This work will be presented at the 58th Annual ACM Symposium on Theory of Computing (STOC) in June 2026 in Salt Lake City, Utah, USA.

Failure of Symmetry of Information for Randomised Computations
Jinqiao Hu (University of Warwick); Yahel Manor (University of Haifa); Igor C. Oliveira (University of Warwick)

The paper describing this research is available here.

The Department of Computer Science is delighted to announce that it has been awarded the Athena Swan Silver Award, recognising our commitment to advancing gender equality for staff and students.

Athena Swan is a UK-wide framework to improve gender equality in higher education. A Silver Award is given to departments that can demonstrate evidence of meaningful progress and impact over a 5-year period – and with a clear and ambitious plan for future action.

In their review, the assessment panel described our submission as "a strong Silver application which addresses all criteria very well."

Many congratulations to Martin Costa for passing his PhD viva, with Prof Long Tran-Thanh (Warwick) and Dr Christian Konrad (Bristol) as examiners. Martin has worked on two different fundamental topics in algorithms - clustering and edge coloring. His work on clustering led to a Google PhD fellowship, and his work on edge coloring (the topic of his thesis) led to a best paper award at STOC. During his PhD spanning 3 years, Martin published 7 papers in STOC/FOCS/SODA, 2 papers in ICML/NeurIPS, and 1 paper in ICALP. We wish him all the very best for the next stage of his career.