Kettle: Short Threshold HAWK Signatures

"Preview Talk" (by team Kettle) @ TCPT3, in reply to the NIST Threshold Call

Abstract: In this talk, we present Kettle, a thresholdized version of the signature scheme HAWK. While HAWK has been attacked recently, its security remains exponential, and its parameters are still competitive compared to existing threshold schemes. We demonstrate that HAWK can be evaluated with as few as 2 online rounds, provide short signatures and low online communication cost. Through a tailored way of daBits, we manage to move the Gaussian sampling and a secret multiplication to the offline phase, lowering the number of online rounds and communication cost. We prove the security of our scheme in the ABB framework, which make our building blocks (eg. Gaussian sampling) reusable in other schemes.

Joint work: Calvin Abou Haidar, Daniel Escudero, Thomas Espitau, Clément Hoffmann, Haruhisa Kosuge, Kaoru Takemure, Mehdi Tibouchi, Hernán Darío Vanegas Madrigal.

Suggested readings

• Preview Writeup (PDF): Kettle: Short Post-Quantum Threshold Signatures from the HAWK Signature Scheme
• HAWK: version 1.1 (February 5, 2025) (PDF)