Adrien Ghosn | Searcharxiv

arXiv2026

Sharing is caring: Attestable and Trusted Workflows out of Distrustful Components

Confidential computing protects data in use within Trusted Execution Environments (TEEs), but current TEEs provide little support for secure communication between components. As a result, pipelines of independently developed and deployed TEEs must trust one another to avoid the leakage of sensitive information they exchange -- a fragile assumption that is unrealistic for modern cloud workloads. We present Mica, a confidential computing architecture that decouples confidentiality from trust. Mica provides tenants with explicit mechanisms to define, restrict, and attest all communication paths between components, ensuring that sensitive data cannot leak through shared resources or interactions. We implement Mica on Arm CCA using existing primitives, requiring only modest changes to the trusted computing base. Our extension adds a policy language to control and attest communication paths among Realms and with the untrusted world via shared protected and unprotected memory and control transfers. Our evaluation shows that Mica supports realistic cloud pipelines with only a small increase to the trusted computing base while providing strong, attestable confidentiality guarantees.

cs.CR↗

arXiv2025

Tyche: Composable Isolation as a Foundation to Manage Trust in the Cloud

Cloud workloads combine software components from different parties to process sensitive data. Each component has its own trust model - it must protect its assets from the rest of the system, yet share sensitive data with components it cannot trust to keep confidential. This tension requires composing isolation boundaries for confidentiality and encapsulation. Unfortunately, the cloud offers no direct way to compose such boundaries, forcing tenants to assemble, deploy, and maintain their own solutions. This paper shifts that burden back to the infrastructure by making composable, attestable isolation a first-class systems abstraction. We present Tyche, a security monitor that centers isolation around a unified composable abstraction: security domains (SDs). An SD is an execution environment whose access to machine resources - memory, cores, devices - is controlled through explicit capabilities. A small set of capability operations enables SDs to partition, share, and reclaim resources; by nesting recursively, SDs compose attestable trust boundaries for confidentiality and encapsulation. Tyche attests these compositions, providing end-to-end security guarantees for workloads made of mutually distrustful components. As a first-class cloud primitive, this single abstraction subsumes enclaves, sandboxes, CVMs, and their compositions. Tyche provides composable isolation without sacrificing compatibility with existing hardware and software stacks. It runs on commodity x86 64 hardware without security extensions, and a RISC-V prototype demonstrates portability across platforms. Our SDK composes isolation for unmodified workloads within SDs with minimal overhead. In a confidential LLM inference scenario with mutually distrustful users, model owners, and cloud providers, the slowdown is just 2% compared to bare-metal Linux.

cs.CR↗