Towards Prompt Chain Deployment Cost Optimization in Zero Trust-Enabled Networks

With its rapid development, AIGC applications have expanded to diverse generative content, including text, images, audio, and videos. To enhance the AIGC's output quality, prompt chains are proposed to structure the generation process. Owing to the prompt's data processing nature, one compromised prompt engineering-enabled server (PES) may propagate vulnerabilities across networks, leading to unintended content generation, system risks, and potential user trust issues. To mitigate these risks, this work adopts a zero-trust (ZT) security framework to protect inter-server communications. We define the problem of prompt chain deployment in ZT-enabled networks(PCD-ZT), with the objective of minimizing total service costs, encompassing both deployment and ZT verification costs. To address this, we introduce the verification-cost-balance (VCB) factor that helps reduce ZT verifications to save the overall service cost and accordingly propose an algorithm called sub-prompt-chain brand and bound (SCBB). Extensive simulations demonstrate that our SCBB achieves overall service cost reductions of 4.67 % and 13.89 %, and cuts verification costs by 11.86 % and 30.50 %, compared to the benchmarks extended from the state-of-the-art.