English

SafeLM: Unified Privacy-Aware Optimization for Trustworthy Federated Large Language Models

Cryptography and Security 2026-04-21 v1 Machine Learning

Abstract

Large language models (LLMs) are increasingly deployed in high-stakes domains, yet a unified treatment of their overlapping safety challenges remains lacking. We present SafeLM, a framework that jointly addresses four pillars of LLM safety: privacy, security, misinformation, and adversarial robustness. SafeLM combines federated training with gradient smartification and Paillier encryption for privacy, integrates defenses against training and inference-time attacks, employs contrastive grounding with calibrated decoding to reduce hallucinations, and introduces alignment-aware binarized aggregation to enhance robustness while maintaining bounded reconstruction quality. Across benchmarks on factuality, toxicity, and membership inference, SafeLM achieves 98.0% harmful content detection accuracy, reduces communication by 96.9%, and lowers gradient inversion PSNR from 31.7 dB to 15.1 dB. Ablations show that each component contributes independently, whereas their integration yields a strong privacy utility efficiency trade-off for deploying trustworthy LLMs.

Keywords

Cite

@article{arxiv.2604.16606,
  title  = {SafeLM: Unified Privacy-Aware Optimization for Trustworthy Federated Large Language Models},
  author = {Noor Islam S. Mohammad and Uluğ Bayazıt},
  journal= {arXiv preprint arXiv:2604.16606},
  year   = {2026}
}