Paper 2024/945

Quantum-Safe Public Key Blinding from MPC-in-the-Head Signature Schemes

Sathvika Balumuri, National Research Council Canada
Edward Eaton, National Research Council Canada
Philippe Lamontagne, National Research Council Canada, Université de Montréal
Abstract

Key blinding produces pseudonymous digital identities by rerandomizing public keys of a digital signature scheme. It is used in anonymous networks to provide the seemingly contradictory goals of anonymity and authentication. Current key blinding schemes are based on the discrete log assumption. Eaton, Stebila and Stracovsky (LATINCRYPT 2021) proposed the first key blinding schemes from lattice assumptions. However, the large public keys and lack of QROM security means they are not ready to replace existing solutions. We present a new way to build key blinding schemes form any MPC-in-the-Head signature scheme. These schemes rely on well-studied symmetric cryptographic primitives and admit short public keys. We prove a general framework for constructing key blinding schemes and for proving their security in the quantum random oracle model (QROM). We instantiate our framework with the recent AES-based Helium signature scheme (Kales and Zaverucha, 2022). Blinding Helium only adds a minor overhead to the signature and verification time. Both Helium and the aforementioned lattice-based key blinding schemes were only proven secure in the ROM. This makes our results the first QROM proof of Helium and the first fully quantum-safe public key blinding scheme.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
Keywords
Key BlindingMPC-in-the-Headpost-quantumQROM
Contact author(s)
Philippe Lamontagne2 @ cnrc-nrc gc ca
History
2024-06-13: approved
2024-06-12: received
See all versions
Short URL
https://ia.cr/2024/945
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2024/945,
      author = {Sathvika Balumuri and Edward Eaton and Philippe Lamontagne},
      title = {Quantum-Safe Public Key Blinding from {MPC}-in-the-Head  Signature Schemes},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/945},
      year = {2024},
      url = {https://eprint.iacr.org/2024/945}
}
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