End-to-End Cryptographic Provenance for LLM API Routing Chains

TL;DR: What if every step your API request took left a cryptographic breadcrumb, making it impossible for any router to tamper with your data unnoticed? Let’s prototype a system where each router in the LLM supply chain cryptographically signs its handling of requests and responses, so any tampering or deviation from expected behavior is provable and traceable. The initial experiment would wrap JSON payloads in chained signatures, testing detection rates for payload injection and exfiltration attacks.

Research Question: Can cryptographic provenance chaining across API routers provide tamper-evident guarantees and forensic traceability for LLM toolcall payloads, thereby preventing or detecting malicious intermediary attacks?

Hypothesis: Implementing cryptographic provenance—where each router signs its actions—will significantly reduce undetected payload injection and secret exfiltration by ensuring any unauthorized modification is immediately detectable by the client or upstream provider.

Experiment Plan: Design a protocol where each API router appends a digital signature (using, e.g., Ed25519) to the payload as it passes through. Simulate multi-hop API routing with benign and malicious routers (some attempting payload injection or exfiltration). Analyze the ability to detect tampering at the client and/or upstream LLM provider. Measure introduced latency and failure rates, and compare to the original client-side anomaly screening from the Mine proxy.

References:

• Liu, H., Shou, C., Wen, H., Chen, Y., Fang, R. J., & Feng, Y. (2026). Your Agent Is Mine: Measuring Malicious Intermediary Attacks on the LLM Supply Chain.
• Sai, T., Pyatlo, T., & Kumar, D. (2025). A Comprehensive Framework for Advanced API Security and Real-Time Monitoring. 2025 Innovations in Power and Advanced Computing Technologies (i-PACT).
• Ben Hassen, A., Lafourcade, P., Mahmoud, D., & Puys, M. (2025). Formal Analysis of SDNsec: Attacks and Corrections for Payload, Route Integrity and Accountability. ACM Asia Conference on Computer and Communications Security.