Paper 2024/1941
Universally Composable Server-Supported Signatures for Smartphones
, Cybernetica (Estonia), Tallinn University of Technology, Cybernetica (Estonia), Tallinn University of Technology, Cybernetica (Estonia)Abstract
Smart-ID is an application for signing and authentication provided as a service to residents of Belgium, Estonia, Latvia and Lithuania. Its security relies on multi-prime server-supported RSA, password-authenticated key shares and clone detection mechanism. Unfortunately, the security properties of the underlying protocol have been specified only in ``game-based'' manner. There is no corresponding ideal functionality that the actual protocol is shown to securely realize in the universal composability (UC) framework. In this paper, we remedy that shortcoming, presenting the functionality (optionally parameterized with a non-threshold signature scheme) and prove that the existing Smart-ID protocol securely realizes it. Additionally, we present a server-supported protocol for generating ECDSA signatures and show that it also securely realizes the proposed ideal functionality in the Global Random Oracle Model (UC+GROM).
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Preprint.
- Keywords
- Smart-IDSplitKeyuniversal composabilityECDSARSAserver-supported signatures
- Contact author(s)
-
nikita snetkov @ cyber ee
jelizaveta vakarjuk @ cyber ee
peeter laud @ cyber ee - History
- 2024-12-02: approved
- 2024-11-29: received
- See all versions
- Short URL
- https://ia.cr/2024/1941
- License
-
CC BY-NC-ND
BibTeX
@misc{cryptoeprint:2024/1941,
author = {Nikita Snetkov and Jelizaveta Vakarjuk and Peeter Laud},
title = {Universally Composable Server-Supported Signatures for Smartphones},
howpublished = {Cryptology {ePrint} Archive, Paper 2024/1941},
year = {2024},
url = {https://eprint.iacr.org/2024/1941}
}
