Abstract: Threshold signing research progressed a lot in the last three years, especially for ECDSA, which is less MPC-friendly than Schnorr-based signatures such as EdDSA. This progress was mainly driven by blockchain applications, and boosted by breakthrough results concurrently published by Lindell and by Gennaro & Goldfeder. Since then, several research teams published threshold signature schemes with different features, design trade-offs, building blocks, and proof techniques. Furthermore, threshold signing is now deployed within major organizations to protect large amounts of digital assets.
In this talk, we start by exploring some of the use cases for TSS including applications to cryptocurrency custody.
We then describe a general threshold ECDSA protocol using an MPC framework, as well as various building blocks that can be used to implement this scheme.
Finally, we highlight some security vulnerabilities that can arise in real world deployments of TSS.
Jean-Philippe (JP) Aumasson is the Chief Security Officer and cofounder of Taurus Group, a Swiss financial tech company specializing in digital assets infrastructure. Since 2006, he has authored more than 60 research articles in the field of cryptography and designed the widely used hash functions BLAKE2 and SipHash. The author of the acclaimed book Serious Cryptography (No Starch Press, 2017), he speaks regularly at information security and technology conferences.
Adrian Hamelink is a Master’s student in Computer Science at the École Polytechnique Fédérale de Lausanne (EPFL). His research interests include isogeny-based cryptography and zero-knowledge proofs. Parallel to his studies, he is working as a part-time research intern for Taurus Group with a strong focus on multi-signature schemes.