,
Venkatesan Guruswami
Creative Commons Attribution 4.0 International license
Introduced in [Christ and Gunn, 2024], pseudorandom error-correcting codes (PRCs) are a new cryptographic primitive with applications in watermarking generative AI models. These are codes where a collection of polynomially many codewords is computationally indistinguishable from random for an adversary that does not have the secret key, but anyone with the secret key is able to efficiently decode corrupted codewords. In this work, we examine the assumptions under which PRCs with robustness to a constant error rate exist.
1) We show that if both the planted hyperloop assumption introduced in [Andrej Bogdanov et al., 2023] and security of a version of Goldreich’s PRG hold, then there exist public-key PRCs for which no efficient adversary can distinguish a polynomial number of codewords from random with better than o(1) advantage.
2) We revisit the construction of [Christ and Gunn, 2024] and show that it can be based on a wider range of assumptions than presented in [Christ and Gunn, 2024]. To do this, we introduce a weakened version of the planted XOR assumption which we call the weak planted XOR assumption and which may be of independent interest.
3) We initiate the study of PRCs which are secure against space-bounded adversaries. We show how to construct secret-key PRCs of length O(n) which are unconditionally indistinguishable from random by poly(n) time, O(n^{1.5-ε}) space adversaries.
@InProceedings{ghentiyala_et_al:LIPIcs.APPROX/RANDOM.2025.54,
author = {Ghentiyala, Surendra and Guruswami, Venkatesan},
title = {{New Constructions of Pseudorandom Codes}},
booktitle = {Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2025)},
pages = {54:1--54:22},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-397-3},
ISSN = {1868-8969},
year = {2025},
volume = {353},
editor = {Ene, Alina and Chattopadhyay, Eshan},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.APPROX/RANDOM.2025.54},
URN = {urn:nbn:de:0030-drops-244202},
doi = {10.4230/LIPIcs.APPROX/RANDOM.2025.54},
annote = {Keywords: Error-correcting codes, Watermarking, Pseudorandomness}
}