Matchmaking encryption for NC1 circuits without obfuscation

Gao, Ying

doi:10.1016/j.tcs.2026.115841

Matchmaking encryption for NC1 circuits without obfuscation

2026-05-02

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DOI：10.1016/j.tcs.2026.115841

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Matchmaking encryption (ME) is a new form of encryption proposed by Ateniese et al. (CRYPTO, 2019). Constructing an ME scheme that supports complex functions without relying on obfuscation is an important area of research, but it has seen limited success despite significant effort. Existing ME schemes either focus on very restricted policies (i.e., for identity matching), or require obfuscation techniques. In this paper, we propose the first ME construction that supports NC1 circuits without using obfuscation. Our results can be summarized as follows. (1) We propose an ME scheme for NC1 circuits from LWE and pairings, with provable security in the generic group model (GGM). (2) We further propose an ME scheme for NC1 circuits in the standard model, by leveraging inner product functional encryption and using the KOALA knowledge assumption. Technically, we follow the blueprint of Francati et al. (Eurocrypt, 2023) but start from the two-input attribute-based encryption by Agrawal et al. (CRYPTO, 2022), which allows for a form of "linking" between two independently generated ciphertexts. In terms of security, our schemes protect the sender's privacy, prove the authenticity of sender data, and ensure that receivers without access privileges remain uninformed about any information.

Keywords:

Matchmaking encryption

Predicate encryption

Learning with errors

Pairing

NC1

Matchmaking encryption for NC1 circuits without obfuscation

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