News
Accepted Papers at Eurocrypt 2026
Several papers co-authored by ATHENE researchers were accepted at this year’s Annual International Conference on the Theory and Applications of Cryptographic Techniques, known as Eurocrypt. The conference is one of the most prestigious and influential conferences worldwide in the field of cryptography. It is part of the International Association for Cryptologic Research (IACR)’s “IACR Flagship Conference” series. Leading cryptographers from academia and industry around the world come together to discuss their latest research findings.
The accepted papers are the following:
When Trying to Catch Cheaters Breaks the MPC: Breaking and Fixing Delayed Consistency Checks in Trident, Fantastic Four, SWIFT, and Quad
Authors: Andreas Brüggemann, Thomas Schneider
In the paper, the researchers describe a fundamental vulnerability in a family of protocols for secure multi-party computation (MPC): If consistency checks, designed to detect misconduct by individual parties, are bundled and postponed to the end of the protocol execution for efficiency reasons, a malicious party can manipulate the computation in such a way that the subsequent consistency checks allow it to reconstruct confidential inputs from other parties. The protocols affected are Trident, Fantastic Four, SWIFT, and Quad, as well as their implementation in the widely used MP-SPDZ framework and other open-source MPC tools. Until now, this vulnerability had eluded the formal security analyses of the affected protocols, as the optimization appeared innocuous and was therefore ignored in the analyses. The paper demonstrates why even the smallest optimization of a protocol must be consistently included in the formal security proof. In response to the identified vulnerabilities, the team developed a generic repair mechanism that combines all individual checks into a single, secure sub-protocol, disclosing only the overall result: success or failure, without revealing any additional information. The paper was developed as part of the ATHENE project PriDA (https://crypto.athene-center.de/projects)
PDF
Combining Oblivious Pseudorandom Functions
Authors: Sebastian Faller, Marc Fischlin, Julius Hard, Julia Hesse
Veiled pseudorandom functions allow a client to interactively evaluate a random function with a server without revealing its input. Conversely, the server’s key remains secret. Systems such as Microsoft and Cloudflare already use this method. However, the underlying security assumptions of current methods are threatened by quantum computers, so hybrid methods combining classical and quantum-secure solutions are preferred. A combiner is a cryptographic method that merges two security protocols into a single one. The combined protocol is secure as long as at least one of the two original protocols remains secure. In their publication, the researchers prove that ideal combiners for oblivious pseudorandom functions generally do not exist. At the same time, they construct practical combiners with minimal additional effort under additional security assumptions. The work, conducted in collaboration with researchers from IBM Zurich, stems from the ATHENE project “Oblivious Pseudorandom Functions, Revisited.”
The work was carried out as part of the ATHENE project "Oblivious Pseudorandom Functions, Revisited (OPRF)".
PDF
Counter Galois Onion: Fast Non-Malleable Onion Encryption for Tor
Authors: Jean Paul Degabriele, Alessandro Melloni, Jean-Pierre Münch, Martijn Stam
PDF
Eurocrypt 2026 will take place in Rome from May 10 to 14, 2026.
show all news