Abadi, Aydin;
Ristea, Dan;
Grigor, Artem;
Murdoch, Steven;
(2025)
Scalable Time-Lock Puzzle.
In:
(Proceedings) ACM ASIA Conference on Computer and Communications Security.
Association for Computing Machinery (ACM): Hanoi, Vietnam.
(In press).
Preview |
Text
Scalable_Time_Lock_Puzzles_camera_ready (1).pdf - Accepted Version Download (2MB) | Preview |
Abstract
Time-Lock Puzzles (TLPs) enable a client to lock a message such that a server can unlock it only after a specified time. They have diverse applications, such as scheduled payments, secret sharing, and zero-knowledge proofs. In this work, we present a scalable TLP designed for real-world scenarios involving a large number of puzzles, where clients or servers may lack the computational resources to handle high workloads. Our contributions are both theoretical and practical. From a theoretical standpoint, we formally define the concept of a “Delegated Time-Lock Puzzle (D-TLP)”, establish its fundamental properties, and introduce an upper bound for TLPs, addressing a previously overlooked aspect. From a practical standpoint, we introduce the “Efficient Delegated Time-Lock Puzzle” (ED-TLP) protocol, which implements the D-TLP concept. This protocol enables both the client and server to securely outsource their resource-intensive tasks to third-party helpers. It enables realtime verification of solutions and guarantees their delivery within predefined time limits by integrating an upper bound and a fair payment algorithm. ED-TLP allows combining puzzles from different clients, enabling a solver to process them sequentially, significantly reducing computational resources, especially for a large number of puzzles or clients. ED-TLP is the first protocol of its kind. We have implemented ED-TLP and conducted a comprehensive analysis of its performance for up to 10,000 puzzles. The results highlight its significant efficiency in TLP applications, demonstrating that EDTLP securely delegates 99% of the client’s workload and 100% of the server’s workload with minimal overhead.
| Type: | Proceedings paper |
|---|---|
| Title: | Scalable Time-Lock Puzzle |
| Event: | ACM ASIA Conference on Computer and Communications Security |
| Location: | Hanoi, Vietnam |
| Dates: | 25 Aug 2025 - 29 Aug 2025 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1145/3708821.3733907 |
| Publisher version: | https://doi.org/10.1145/3708821.3733907 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. ASIA CCS ’25, Hanoi, Vietnam © 2025 Copyright held by the owner/author(s) |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Computer Science |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10209506 |
Archive Staff Only
 |
View Item |
