### Privacy-Enhancing Group Signcryption Scheme

Sara Ricci, Petr Dzurenda, Jan Hajny, and Lukas Malina

##### Abstract

In the last decades, several signcryption schemes have been proposed for different privacy-enhancing purposes. In this paper, we propose a new privacy-enhancing group signcryption scheme that provides: unforgeability, confidentiality, ciphertext and sender anonymity, traceability, unlinkability, exculpability, coalition-resistance, and unforgeable tracing verification. It is important to notice that the proposed scheme allows a signer to anonymously signcryt a message on the group's behalf (i.e., sender's anonymity). Security analysis of the scheme is also provided. Our proposal is proven to be strongly existentially unforgeable under an adaptive chosen message attack, indistinguishable under an adaptive chosen ciphertext attack, and to provide ciphertext anonymity under an adaptive chosen ciphertext attack. Furthermore, the scheme is extended to work in a multi-receiver scenario, where an authorized group of receivers is able to unsigncrypt the ciphertext. The experimental results show that our scheme is efficient even on computationally restricted devices and can be therefore used in many IoT applications. Signcrypt protocol on smart cards takes less than 1~s (including communication overhead). The time of Unsigncrypt protocol on current ARM devices is negligible (less than 40 ms).

Available format(s)
Category
Cryptographic protocols
Publication info
Preprint. MINOR revision.
Keywords
anonymitygroup signatureselliptic curve cryptosystemimplementationsmart cardszero knowledge
Contact author(s)
ricci @ vutbr cz
History
Short URL
https://ia.cr/2021/1050

CC BY

BibTeX

@misc{cryptoeprint:2021/1050,
author = {Sara Ricci and Petr Dzurenda and Jan Hajny and Lukas Malina},
title = {Privacy-Enhancing Group Signcryption Scheme},
howpublished = {Cryptology ePrint Archive, Paper 2021/1050},
year = {2021},
note = {\url{https://eprint.iacr.org/2021/1050}},
url = {https://eprint.iacr.org/2021/1050}
}

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