Large language models represent significant investments in computation, data,
and engineering expertise, making them extraordinarily valuable intellectual
assets. Nevertheless, these AI assets remain vulnerable to unauthorized
redistribution and commercial exploitation through fine-tuning or black-box
deployment. Current fingerprinting approaches face a fundamental trade-off:
intrinsic methods require full parameter access, while backdoor-based
techniques employ statistically anomalous triggers easily detected and filtered
by adversaries. To address these limitations, we introduce FPEdit, a novel
knowledge-editing framework that injects semantically coherent natural language
fingerprints by modifying a sparse subset of model weights. This ensures
stealthy and precise ownership encoding without degrading the core
functionality. Extensive experiments show that FPEdit achieves $95$-$100\%$
fingerprint retention under both full-parameter fine-tuning and
parameter-efficient adaptation, while preserving performance on 24 downstream
benchmarks. Moreover, FPEdit remains robust under quantization, pruning, and
stochastic decoding, and can embed 10 fingerprint pairs into LLaMA2-7B in under
10 minutes using less than 32 GB of GPU memory, a $70\%$ reduction in resource
requirements compared to existing techniques. These advances establish FPEdit
as the first fingerprinting approach to simultaneously achieve robustness
against adaptation, resistance to detection, and preservation of model utility,
providing a minimally invasive solution for reliable provenance verification of
large language models in adversarial deployment scenarios.