Federated Fine-Tuning of Large Language Models on Resource-Constrained Clients: Technical Approaches, Resource Costs, and Applicability
Review Article  ·  Published: 20 September 2026
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Journal of Reliable and Secure Computing
Volume 2, Issue 3, 2026: 194-211
Review Article Open Access

Federated Fine-Tuning of Large Language Models on Resource-Constrained Clients: Technical Approaches, Resource Costs, and Applicability

1 Department of Automation, Tsinghua University, Beijing 100084, China
2 JD.com, Inc., Beijing 101111, China
3 School of Information and Software Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
4 School of Computing and Information Systems, Singapore Management University, Singapore 188065, Singapore
* Corresponding Authors: Yang Yang, [email protected]; Hairong Lv, [email protected]
Volume 2, Issue 3
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Article Information

Abstract

Federated fine-tuning adapts language models to distributed data and is widely adopted as a privacy-preserving alternative to centralized training, yet constrained clients must still store model weights and training states, execute updates, and communicate with a server. This review examines four composable routes---parameter-efficient and quantized adaptation, backpropagation-free adaptation, proxy or submodel adaptation, and split federated adaptation---through a common framework that traces the objects each endpoint retains, exchanges, and discloses. When a client retains the complete base, reducing adapter state leaves a base-storage floor; boundary communication depends on input dimensions, sequence length, and interaction frequency, so parameter count alone is insufficient. Keeping data local constrains the raw dataset but not the transmitted object: adapter updates, boundary activations, logits, and cached embeddings expose different surfaces, and the encryption, secure-aggregation, or noise mechanisms that protect them add to the same budgets. Server weight sharing removes duplication but retains private states and caches, and combining routes requires recalculating these costs for the resulting protocol. The analysis identifies where savings arise, where costs move, what each route discloses, and which training, deployment, and trustworthiness conditions govern its applicability.

Graphical Abstract

Federated Fine-Tuning of Large Language Models on Resource-Constrained Clients: Technical Approaches, Resource Costs, and Applicability

Keywords

federated learning large language models privacy-preserving computation trustworthy AI parameter-efficient fine-tuning zeroth-order optimization proxy models split learning secure aggregation resource accounting

Data Availability Statement

Not applicable.

Funding

This work was supported in part by the National Natural Science Foundation of China under Grant 62372110, and in part by the Fujian Provincial Natural Science Foundation under Grant 2023J02008.

Conflicts of Interest

Yunheng Shen is affiliated with JD.com, Inc., Beijing 101111, China. The authors declare that this affiliation had no influence on the study design, data collection, analysis, interpretation of the results, or the decision to publish. Yang Yang served as an Associate Editor of the Journal of Reliable and Secure Computing at the time of manuscript submission. To ensure the integrity and impartiality of the peer-review process, Yang Yang was not involved in the editorial handling, peer review, or decision-making for this manuscript, which was handled independently by another editor. The authors declare no other conflicts of interest.

AI Use Statement

The authors declare that ChatGPT-5.6 Sol was used for drafting and language editing of the manuscript. The authors have carefully reviewed, revised, and verified the AI-assisted output and take full responsibility for the content of the manuscript.

Ethical Approval and Consent to Participate

Not applicable.

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Cite This Article

APA Style
Shen, Y., Liu, X., Yang, Y., & Lv, H. (2026). Federated Fine-Tuning of Large Language Models on Resource-Constrained Clients: Technical Approaches, Resource Costs, and Applicability. Journal of Reliable and Secure Computing, 2(3), 194-211. https://doi.org/10.62762/JRSC.2026.225854
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TY  - JOUR
AU  - Shen, Yunheng
AU  - Liu, Xiao
AU  - Yang, Yang
AU  - Lv, Hairong
PY  - 2026
DA  - 2026/09/20
TI  - Federated Fine-Tuning of Large Language Models on Resource-Constrained Clients: Technical Approaches, Resource Costs, and Applicability
JO  - Journal of Reliable and Secure Computing
T2  - Journal of Reliable and Secure Computing
JF  - Journal of Reliable and Secure Computing
VL  - 2
IS  - 3
SP  - 194
EP  - 211
DO  - 10.62762/JRSC.2026.225854
UR  - https://www.icck.org/article/abs/JRSC.2026.225854
KW  - federated learning
KW  - large language models
KW  - privacy-preserving computation
KW  - trustworthy AI
KW  - parameter-efficient fine-tuning
KW  - zeroth-order optimization
KW  - proxy models
KW  - split learning
KW  - secure aggregation
KW  - resource accounting
AB  - Federated fine-tuning adapts language models to distributed data and is widely adopted as a privacy-preserving alternative to centralized training, yet constrained clients must still store model weights and training states, execute updates, and communicate with a server. This review examines four composable routes---parameter-efficient and quantized adaptation, backpropagation-free adaptation, proxy or submodel adaptation, and split federated adaptation---through a common framework that traces the objects each endpoint retains, exchanges, and discloses. When a client retains the complete base, reducing adapter state leaves a base-storage floor; boundary communication depends on input dimensions, sequence length, and interaction frequency, so parameter count alone is insufficient. Keeping data local constrains the raw dataset but not the transmitted object: adapter updates, boundary activations, logits, and cached embeddings expose different surfaces, and the encryption, secure-aggregation, or noise mechanisms that protect them add to the same budgets. Server weight sharing removes duplication but retains private states and caches, and combining routes requires recalculating these costs for the resulting protocol. The analysis identifies where savings arise, where costs move, what each route discloses, and which training, deployment, and trustworthiness conditions govern its applicability.
SN  - 3070-6424
PB  - Institute of Central Computation and Knowledge
LA  - English
ER  - 
BibTeX Format
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@article{Shen2026Federated,
  author = {Yunheng Shen and Xiao Liu and Yang Yang and Hairong Lv},
  title = {Federated Fine-Tuning of Large Language Models on Resource-Constrained Clients: Technical Approaches, Resource Costs, and Applicability},
  journal = {Journal of Reliable and Secure Computing},
  year = {2026},
  volume = {2},
  number = {3},
  pages = {194-211},
  doi = {10.62762/JRSC.2026.225854},
  url = {https://www.icck.org/article/abs/JRSC.2026.225854},
  abstract = {Federated fine-tuning adapts language models to distributed data and is widely adopted as a privacy-preserving alternative to centralized training, yet constrained clients must still store model weights and training states, execute updates, and communicate with a server. This review examines four composable routes---parameter-efficient and quantized adaptation, backpropagation-free adaptation, proxy or submodel adaptation, and split federated adaptation---through a common framework that traces the objects each endpoint retains, exchanges, and discloses. When a client retains the complete base, reducing adapter state leaves a base-storage floor; boundary communication depends on input dimensions, sequence length, and interaction frequency, so parameter count alone is insufficient. Keeping data local constrains the raw dataset but not the transmitted object: adapter updates, boundary activations, logits, and cached embeddings expose different surfaces, and the encryption, secure-aggregation, or noise mechanisms that protect them add to the same budgets. Server weight sharing removes duplication but retains private states and caches, and combining routes requires recalculating these costs for the resulting protocol. The analysis identifies where savings arise, where costs move, what each route discloses, and which training, deployment, and trustworthiness conditions govern its applicability.},
  keywords = {federated learning, large language models, privacy-preserving computation, trustworthy AI, parameter-efficient fine-tuning, zeroth-order optimization, proxy models, split learning, secure aggregation, resource accounting},
  issn = {3070-6424},
  publisher = {Institute of Central Computation and Knowledge}
}

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CC BY Copyright © 2026 by the Author(s). Published by Institute of Central Computation and Knowledge. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
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