Welcome to the resource topic for 2025/058
Title:
Skyscraper: Fast Hashing on Big Primes
Authors: Clémence Bouvier, Lorenzo Grassi, Dmitry Khovratovich, Katharina Koschatko, Christian Rechberger, Fabian Schmid, Markus Schofnegger
Abstract:Arithmetic hash functions defined over prime fields have been actively developed and used in verifiable computation (VC) protocols. Among those, elliptic-curve-based SNARKs require large ((256)-bit and higher) primes. Such hash functions are notably slow, losing a factor of up to (1000) compared to regular constructions like SHA-2/3.
In this paper, we present the hash function \textsf{Skyscraper}, which is aimed at large prime fields and provides major improvements compared to \texttt{Reinforced Concrete} and \texttt{Monolith}. First, the design is exactly the same for all large primes, which simplifies analysis and deployment. Secondly, it achieves a performance comparable to cryptographic hash standards by using low-degree non-invertible transformations and minimizing modulo reductions. Concretely, it hashes two (256)-bit prime field (BLS12-381 curve scalar field) elements in (135) nanoseconds, whereas SHA-256 needs (42) nanoseconds on the same machine.
The low circuit complexity of \textsf{Skyscraper}, together with its high native speed, should allow a substantial reduction in many VC scenarios, particularly in recursive proofs.
ePrint: https://eprint.iacr.org/2025/058
See all topics related to this paper.
Feel free to post resources that are related to this paper below.
Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.
For more information, see the rules for Resource Topics .