How to use your brain for cryptography without trustworthy machines

Wakaha Ogata; Toi Tomita; Kenta Takahashi; Masakatsu Nishigaki

Paper 2025/026

How to use your brain for cryptography without trustworthy machines

Wakaha Ogata

, Institute of Science Tokyo

Toi Tomita

, Yokohama National University

Kenta Takahashi

, Hitachi Ltd.

Masakatsu Nishigaki

, Shizuoka University

Abstract

In this work, we study cryptosystems that can be executed securely without fully trusting all machines, but only trusting the user's brain. This paper focuses on signature scheme. We first introduce a new concept called ``server-aided in-brain signature,'' which is a cryptographic protocol between a human brain and multiple servers to sign a message securely even if the user's device and servers are not completely trusted. Second, we propose a concrete scheme that is secure against mobile hackers in servers and malware infecting user's devices.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
Keywords: Digital signature untrusted machine malware mobile hacker
Contact author(s): ogata w aa @ m titech ac jp
tomita-toi-sk @ ynu ac jp
kenta takahashi bw @ hitachi com
nishigaki @ inf shizuoka ac jp
History: 2025-01-08: approved; 2025-01-08: received; See all versions
Short URL: https://ia.cr/2025/026
License: CC BY

BibTeX

@misc{cryptoeprint:2025/026,
      author = {Wakaha Ogata and Toi Tomita and Kenta Takahashi and Masakatsu Nishigaki},
      title = {How to use your brain for cryptography without trustworthy machines},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/026},
      year = {2025},
      url = {https://eprint.iacr.org/2025/026}
}