CaSCaDE: (Time-Based) Cryptography from Space Communications DElay
Paper i proceeding, 2024

Time-based cryptographic primitives such as Time-Lock Puzzles (TLPs) and Verifiable Delay Functions (VDFs) have proven to be pivotal in several areas of cryptography. All existing candidate constructions, however, guarantee time-delays based on the average hardness of sequential computational problems. This means that any algorithmic or hardware improvement affects parameter choices and may turn deployed systems insecure. To address this issue, we investigate how to build time-based cryptographic primitives where delays depend on sources other than sequential computations: namely, transmission delays caused by sequential communication. We explore sequential communication delays that arise when sending a message through a constellation of satellites in Space. This setting has the advantage that distances between protocol participants are guaranteed as positions of satellites are observable from Earth, moreover delay lower bounds are unconditional and can be easily computed using the laws of Physics (the speed of light bounds transmission speed). We introduce proofs of sequential communication delay (SCD) in the Universal Composability framework, that can be used to convince a verifier that a message has accrued delay by traversing a path among a set of scattered satellites. With our SCD proofs we realize the first proposals of Publicly Verifiable TLPs and VDFs whose delay guarantees are rooted on physical limits, rather than ever-decreasing computational hardness. Finally, our notion of SCD paves the way to the first Delay Encryption construction not based on supersingular isogenies.

Författare

Carsten Baum

Danmarks Tekniske Universitet (DTU)

Bernardo David

IT-Universitetet i Kobenhavn

Elena Pagnin

Chalmers, Data- och informationsteknik, Informationssäkerhet

Akira Takahashi

J.P. Morgan AI Research & J.P. Morgan AlgoCRYPT CoE

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

03029743 (ISSN) 16113349 (eISSN)

Vol. 14973 LNCS 252-274
9783031710698 (ISBN)

14th Conference on Security and Cryptography for Networks, SCN 2024
Amalfi, Italy,

Ämneskategorier

Datavetenskap (datalogi)

DOI

10.1007/978-3-031-71070-4_12

Mer information

Senast uppdaterat

2024-10-02