ShieldLink: Retry‑Aware Authenticated Encryption for Secure and Reliable Chiplet Interconnects

Abstract

Chiplet-based systems-in-package increasingly rely on high-speed die-to-die links such as UCIe and CXL, where link- layer retry mechanisms and authenticated encryption are of- ten implemented as separate reliability and security func- tions. This separation can create a time-of-check/time-of- use risk when acknowledgments advance before authentication completes. This study introduces ShieldLink, a retry-aware authenticated-encryption protocol that integrates link-layer delivery, buffer retirement, and cryptographic verification to enable secure and reliable chiplet interconnects. Shield- Link formalizes a deliverability invariant requiring CRC, se- quence, and AEAD verification before receiver advancement. It defines per-frame authentication (Mode A) and epoch authentication (Mode B), evaluates them with a discrete- event Gilbert–Elliott burst-error model, and includes bounded safety exploration plus RTL control-plane resource sizing. Mode A removes the validity-before-verification race while improving goodput by approximately 2.4–2.5 percentage points over the secure naive baseline at representative burst prob- abilities. Mode B improves wire efficiency, reaching about 0.926 at M = 32, but its epoch-retransmission cost causes a crossover around πB ≈ 0.04 under the default β = 0.2 stress regime. The results show that authenticated delivery must be treated as part of retry semantics rather than an afterthought. ShieldLink provides an auditable design invariant and practi- cal guidance on mode selection for future secure chiplet inter- connect adapters, with relevance to SDG 9: Industry, Innovation and Infrastructure.