### Identity-Based Higncryption

Hongbing Wang and Yunlei Zhao

##### Abstract

Identity-based cryptography (IBC) is fundamental to security and privacy protection. Identity-based authenticated encryption (i.e., signcryption) is an important IBC primitive, which has numerous and promising applications. After two decades of research on signcryption,recently a new cryptographic primitive, named higncryption, was proposed. Higncryption can be viewed as privacy-enhanced signcryption, which integrates public key encryption, entity authentication, and identity concealment (which is not achieved in signcryption) into a monolithic primitive. Here, briefly speaking, identity concealment means that the transcript of protocol runs should not leak participants' identity information. In this work, we propose the first identity-based higncryption (IBHigncryption). The most impressive feature of IBHigncryption, among others, is its simplicity and efficiency. The proposed IBHigncryption scheme is essentially as efficient as the fundamental CCA-secure Boneh-Franklin IBE scheme [18], while offering entity authentication and identity concealment simultaneously. Compared to the identity-based signcryption scheme [11], which is adopted in the IEEE P1363.3 standard, our IBHigncryption scheme is much simpler, and has significant efficiency advantage in total. Besides, our IBHigncryption enjoys forward ID-privacy, receiver deniability and x-security simultaneously. In addition, the proposed IBHigncryption has a much simpler setup stage with smaller public parameters, which in particular does not have the traditional master public key. Higncryption is itself one-pass identity-concealed authenticated key exchange without forward security for the receiver. Finally, by applying the transformation from higncryption to identity-concealed authenticated key exchange (CAKE), we get three-pass identity-based CAKE (IB-CAKE) with explicit mutual authentication and strong security (in particular, perfect forward security for both players). Specifically, the IB-CAKE protocol involves the composition of two runs of IBHigncryption, and has the following advantageous features inherited from IBHigncryption: (1) single pairing operation: each player performs only a single pairingoperation; (2) forward ID-privacy; (3) simple setup without master public key; (4) strong resilience to ephemeral state exposure, i.e., x-security; (5) reasonable deniability.

Note: Corrected the typo that Figure-5 was identical to Figure-4.

Available format(s)
Category
Public-key cryptography
Publication info
Preprint. Minor revision.
Keywords
Identity-based cryptographySigncryptionIdentity-concealmentHigncryption
Contact author(s)
ylzhao @ fudan edu cn
History
2019-08-03: last of 3 revisions
See all versions
Short URL
https://ia.cr/2019/106

CC BY

BibTeX

@misc{cryptoeprint:2019/106,
author = {Hongbing Wang and Yunlei Zhao},
title = {Identity-Based Higncryption},
howpublished = {Cryptology ePrint Archive, Paper 2019/106},
year = {2019},
note = {\url{https://eprint.iacr.org/2019/106}},
url = {https://eprint.iacr.org/2019/106}
}

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