Paper 2025/1773 Original: eprint.iacr.org/2025/1773 ↗
Impossibility of VDFs in the ROM: The Complete Picture
Abstract
We study whether Verifiable Delay Functions (VDFs) can be constructed in the (plain) Random Oracle Model (ROM) without any computational assumptions. A first partial answer to this question is due to Mahmoody, Smith, and Wu [ICALP 2020] where they rule out perfectly unique VDFs in the ROM. Building on this result, Guan, Riazanov, and Yuan [CRYPTO 2025] prove that VDFs with computational uniqueness and public-coin setup are impossible in the ROM. These works leave open the possibility of constructing computationally unique VDFs with private-coin setup in the ROM. We resolve this problem and additionally rule out computationally-unique VDFs with computationally expensive private-coin setup in the ROM.
Metadata
- Available format(s)
PDF- Category
- Foundations
- Publication info
- Preprint.
- History
- 2026-03-05: last updated
- 2025-09-28: published
- Short URL
- https://ia.cr/2025/1773
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2025/1773,
author = {Hamza Abusalah and Karen Azari and Chethan Kamath and Erkan Tairi and Maximilian von Consbruch},
title = {Impossibility of VDFs in the ROM: The Complete Picture},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/1773},
year = {2025},
url = {https://eprint.iacr.org/2025/1773}
}