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Warwick undergraduate Sasha Shaw has helped uncover and responsibly disclose a security flaw in a UK mobile network as part of his dissertation project, supervised by Professor Feng Hao. The vulnerability has now been patched, and Sasha has been recognised by BT on its responsible disclosure Hall of Fame. His project examined the security of the SIP stack over VoLTE and highlights the real-world impact that student cybersecurity research can have.

In a recent work, visiting undergraduate student Yahel Manor and Warwick DCS researchers and 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 (ÉñÂí¸£ÀûӰƬ); Yahel Manor (University of Haifa); Igor C. Oliveira (ÉñÂí¸£ÀûӰƬ)

The paper describing this research is available .