Professor Bart Preneel (KU Leuven, Belgium)
To celebrate the achievements of IPN in the past 25 years, IPN is organising a special, online series of colloquia in which world-renowned computer scientists give their view on the progress in, and future of the field of computer science. These colloquia will feature thought-provoking presentations that are of interest to a broad (academic) computer science audience. Although these colloquia are initially aimed at the Dutch computer science community, they are open to interested people around the world!
Abstract
The Crypto Wars represent the ongoing tension between government efforts to access encrypted data for national security and the protection of privacy. This talk will provide a brief history of these conflicts, including attempts to suppress cryptographic research, impose secure communication controls (e.g., the Clipper Chip), access encrypted devices (Apple vs. FBI), and deploy spyware (e.g., NSO Group). Recently, focus has shifted to client-side scanning—filtering content on devices before encryption or after decryption—ostensibly to detect Child Sexual Abuse Material (CSAM), but also positioned for anti-terrorism and crime efforts.
However, client-side scanning undermines end-to-end encryption, is prone to misuse, and lacks proven effectiveness. Perceptual hash functions used to detect known CSAM often yield high false positive and negative rates, as shown in our recent research. Regulatory proposals promoting AI for detecting AI-generated CSAM raise further concerns about reliability.
In Spring 2025, the ProtectEU initiative launched a roadmap to explore lawful access technologies for 2026, marking a new phase in the crypto war.
Despite encryption challenges, law enforcement has amassed vast metadata and surveillance tools. Rather than weakening encryption, efforts should focus on robust cybersecurity, transparency in surveillance, and a societal debate to balance security with rights.
Date, Time, Location
The colloquium will take place on October 28, 2025, 16:00 – 17:00 (CEST).
The colloquium will be hosted as a Teams webinar. You can join the colloquium here.
We are looking forward to seeing you there!
Afterwards you can find the recording here.