Presentation at EUROCRYPT 2026
EUROCRYPT (the Annual International Conference on the Theory and Applications of Cryptographic Techniques) is one of the leading international conferences in the field of cryptography. The conference primarily focuses on theoretical and foundational aspects of cryptography, while also covering a broad range of topics in applied cryptography. Typical research areas include public-key cryptography, zero-knowledge proofs, secure multiparty computation, blockchain and distributed cryptography, cryptographic protocols, cryptographic hardness assumptions, and privacy-preserving technologies.
At EUROCRYPT 2026, which will take place in Rome, Italy, from 10 to 14 May 2026, researchers Paul Gerhart, Davide Li Calsi, Luigi Russo, and Dominique Schröder (all from the Privacy Enhancing Technologies Research Group, TU Wien Informatics) will present new work titled “Fully-Adaptive Two-Round Threshold Schnorr Signatures from DDH.”
Digital signatures are a fundamental technology used to secure online communication, financial transactions, and distributed systems such as blockchains. In many modern applications, it is important that signatures are not produced by a single individual but rather by a group of participants acting together. Threshold signature schemes address this need by allowing a subset of participants to jointly produce a single valid signature. The resulting signature is indistinguishable from a standard Schnorr signature, meaning it can be verified by existing systems without modification.
The work to be presented at EUROCRYPT 2026 introduces a new approach that improves both the security and efficiency of such collaborative signature systems. In particular, the proposed scheme protects against adaptive attacks, in which an adversary may attempt to compromise participants during the signing process. Achieving strong protection against these attacks while maintaining high efficiency has long been a challenge in cryptographic research.
The proposed protocol requires only two rounds of communication, helping ensure low latency and making it suitable for real-world distributed systems. To demonstrate practical feasibility, the researchers implemented a prototype and evaluated its performance on standard hardware. The results indicate that the scheme meets efficiency requirements highlighted in recent recommendations by the U.S. National Institute of Standards and Technology (NIST).
This research represents an important step toward secure and deployable collaborative signature systems, which are increasingly important for applications such as blockchain infrastructures, distributed financial services, and other systems that rely on shared cryptographic control.