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arXiv · 2601.13031

Post-Quantum Secure Aggregation via Code-Based Homomorphic Encryption

Sebastian Bitzer·Maximilian Egger·Mumin Liu·Antonia Wachter-Zeh
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Abstract

Secure aggregation enables aggregation of inputs from multiple parties without revealing individual contributions to the server or other clients. Existing post-quantum approaches based on homomorphic encryption offer practical efficiency but predominantly rely on lattice-based hardness assumptions. We present a code-based alternative for secure aggregation by instantiating a general framework based on key- and message-additive homomorphic encryption under the Learning Parity with Noise (LPN) assumption. Our construction employs a committee-based decryptor realized via secret sharing and incorporates a Chinese Remainder Theorem (CRT)-based optimization to reduce the communication costs of LPN-based instantiations. We analyze the security of the proposed scheme under a new Hint-LPN assumption and show that it is equivalent to standard LPN for suitable parameters. Finally, we evaluate performance and identify regimes in which our approach outperforms information-theoretically secure aggregation protocols.

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Sebastian Bitzer, Maximilian Egger, Mumin Liu, Antonia Wachter-Zeh. 2026-01-19. Post-Quantum Secure Aggregation via Code-Based Homomorphic Encryption. https://arxiv.org/abs/2601.13031

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