EaaS/PIN Synergy: Advances and Challenges Secure Path Verification

The proliferation of resource-constrained devices in Internet of Things (IoT) environments has amplified the demand for scalable, secure, and efficient cryptographic services. While Encryption-as-a-Service (EaaS) models enable offloading cryptographic tasks to trusted infrastructure, critical challenges remain regarding path integrity, trust management, and resilience to adversarial threats in multi-domain networks. This paper introduces EaaS/PIN, a unified framework that combines cryptographically verifiable path integrity, user-centric trust scoring, collaborative threat intelligence, and machine learning-driven path selection across distributed Autonomous Systems (ASs). The framework integrates: (i) a novel anonymity protocol to conceal complete routes from intermediary ASs, (ii) lightweight, customizable encryption suitable for IoT and edge environments, (iii) real-time, AI-based path recommendation leveraging dynamic trust and performance metrics, and (iv) a blockchain-inspired audit mechanism for tamper-evident reporting and accountability. Comprehensive mathematical modeling, algorithms, and a detailed case study focused on secure data transmission in a multi-AS smart city network demonstrate that EaaS/PIN significantly enhances routing security, reduces latency, and ensures transparent and verifiable operations even under adversarial conditions. Experimental results confirm robust detection of path manipulation and compromised ASs, as well as measurable performance gains over baseline solutions. The proposed framework paves the way for scalable, user-aware, and resilient cryptographic services in next-generation heterogeneous network infrastructures.