AlphaFL: Secure Aggregation with Malicious2 Security for Federated Learning against Dishonest Majority
Publikation: Beitrag in Fachzeitschrift › Forschungsartikel › Beigetragen › Begutachtung
Beitragende
Abstract
Federated learning (FL) proposes to train a global machine learning model across distributed datasets. However, the aggregation protocol as the core component in FL is vulnerable to well-studied attacks, such as inference attacks, poisoning attacks [71] and malicious participants who try to deviate from the protocol [24]. Therefore, it is crucial to achieve both malicious security and poisoning resilience from cryptographic and FL perspectives, respectively. Prior works either achieve incomplete malicious security [76], address issues by using expensive cryptographic tools [22, 59] or assume the availability of a clean dataset on the server side [32]. In this work, we propose AlphaFL, a two-server secure aggregation protocol achieving both malicious security in the universal composability (UC) framework [19] and poisoning resilience in FL (thus malicious2) against a dishonest majority. We design maliciously secure multi-party computation (MPC) protocols [24, 26, 48] and introduce an efficient input commitment protocol tolerating server-client collusion (dishonest majority). We also propose an efficient input commitment protocol for the non-collusion case (honest majority), which triples the efficiency in time and quadruples that in communication, compared to the state-of-the-art solution in MP-SPDZ [46]. To achieve poisoning resilience, we carry out 𝐿∞ and 𝐿2-Norm checks with a dynamic L_2-Norm bound by introducing a novel silent select protocol, which improves the runtime by at least two times compared to the classic select protocol. Combining these, AlphaFL achieves malicious2 security at a cost of 25% − 79% more runtime overhead than the state-of-the-art semi-malicious counterpart Elsa [76], with even less communication cost.
Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 348-368 |
| Seitenumfang | 21 |
| Fachzeitschrift | Proceedings on privacy enhancing technologies : PoPETs |
| Jahrgang | 2025 |
| Ausgabenummer | 4 |
| Publikationsstatus | Veröffentlicht - Okt. 2025 |
| Peer-Review-Status | Ja |
| Extern publiziert | Ja |
Externe IDs
| ORCID | /0000-0002-0466-562X/work/199216541 |
|---|---|
| Mendeley | 6163c8a6-35a0-385c-a517-0156d8f68a15 |
| unpaywall | 10.56553/popets-2025-0134 |