On Explicit Constructions of Extremely Depth Robust Graphs

Autor: Blocki, Jeremiah, Cinkoske, Mike, Lee, Seunghoon, Son, Jin Young
Rok vydání: 2021
Předmět:
DOI: 10.48550/arxiv.2110.04190
Popis: A directed acyclic graph $G=(V,E)$ is said to be $(e,d)$-depth robust if for every subset $S \subseteq V$ of $|S| \leq e$ nodes the graph $G-S$ still contains a directed path of length $d$. If the graph is $(e,d)$-depth-robust for any $e,d$ such that $e+d \leq (1-\epsilon)|V|$ then the graph is said to be $\epsilon$-extreme depth-robust. In the field of cryptography, (extremely) depth-robust graphs with low indegree have found numerous applications including the design of side-channel resistant Memory-Hard Functions, Proofs of Space and Replication, and in the design of Computationally Relaxed Locally Correctable Codes. In these applications, it is desirable to ensure the graphs are locally navigable, i.e., there is an efficient algorithm $\mathsf{GetParents}$ running in time $\mathrm{polylog} |V|$ which takes as input a node $v \in V$ and returns the set of $v$'s parents. We give the first explicit construction of locally navigable $\epsilon$-extreme depth-robust graphs with indegree $O(\log |V|)$. Previous constructions of $\epsilon$-extreme depth-robust graphs either had indegree $\tilde{\omega}(\log^2 |V|)$ or were not explicit.
Comment: 12 pages, 1 figure. This is the full version of the paper published at STACS 2022. We noticed a mistake in the references for the computational intractability of the depth robustness of the graphs and fixed it
Databáze: OpenAIRE