ProToken: Token-Level Attribution for Federated Large Language Models

Fuente: arXiv
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Auteurs principaux: Gill, Waris, Humayun, Ahmad, Anwar, Ali, Gulzar, Muhammad Ali
Format: Preprint
Publié: 2026
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author Gill, Waris
Humayun, Ahmad
Anwar, Ali
Gulzar, Muhammad Ali
author_facet Gill, Waris
Humayun, Ahmad
Anwar, Ali
Gulzar, Muhammad Ali
contents Federated Learning (FL) enables collaborative training of Large Language Models (LLMs) across distributed data sources while preserving privacy. However, when federated LLMs are deployed in critical applications, it remains unclear which client(s) contributed to specific generated responses, hindering debugging, malicious client identification, fair reward allocation, and trust verification. We present ProToken, a novel Provenance methodology for Token-level attribution in federated LLMs that addresses client attribution during autoregressive text generation while maintaining FL privacy constraints. ProToken leverages two key insights to enable provenance at each token: (1) transformer architectures concentrate task-specific signals in later blocks, enabling strategic layer selection for computational tractability, and (2) gradient-based relevance weighting filters out irrelevant neural activations, focusing attribution on neurons that directly influence token generation. We evaluate ProToken across 16 configurations spanning four LLM architectures (Gemma, Llama, Qwen, SmolLM) and four domains (medical, financial, mathematical, coding). ProToken achieves 98% average attribution accuracy in correctly localizing responsible client(s), and maintains high accuracy when the number of clients are scaled, validating its practical viability for real-world deployment settings.
format Preprint
id arxiv_https___arxiv_org_abs_2601_19672
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ProToken: Token-Level Attribution for Federated Large Language Models
Gill, Waris
Humayun, Ahmad
Anwar, Ali
Gulzar, Muhammad Ali
Machine Learning
Artificial Intelligence
Software Engineering
Federated Learning (FL) enables collaborative training of Large Language Models (LLMs) across distributed data sources while preserving privacy. However, when federated LLMs are deployed in critical applications, it remains unclear which client(s) contributed to specific generated responses, hindering debugging, malicious client identification, fair reward allocation, and trust verification. We present ProToken, a novel Provenance methodology for Token-level attribution in federated LLMs that addresses client attribution during autoregressive text generation while maintaining FL privacy constraints. ProToken leverages two key insights to enable provenance at each token: (1) transformer architectures concentrate task-specific signals in later blocks, enabling strategic layer selection for computational tractability, and (2) gradient-based relevance weighting filters out irrelevant neural activations, focusing attribution on neurons that directly influence token generation. We evaluate ProToken across 16 configurations spanning four LLM architectures (Gemma, Llama, Qwen, SmolLM) and four domains (medical, financial, mathematical, coding). ProToken achieves 98% average attribution accuracy in correctly localizing responsible client(s), and maintains high accuracy when the number of clients are scaled, validating its practical viability for real-world deployment settings.
title ProToken: Token-Level Attribution for Federated Large Language Models
topic Machine Learning
Artificial Intelligence
Software Engineering
url https://arxiv.org/abs/2601.19672