Shielded but Lightweight: Building Practical Confidential Containers with ARM CCA

2026-05-25

AI Summary

This work addresses the challenge of supporting short-lived workloads in existing confidential containers based on micro-VMs, which suffer from software stack complexity. It presents the first approach that directly leverages the ARM Confidential Computing Architecture (CCA) to construct a lightweight confidential container runtime. In this design, each container executes as an isolated Container Realm, while a dedicated System Realm provides essential system services and resource management. By employing exception forwarding and shared buffer mechanisms, the system achieves strong isolation while significantly reducing the trusted computing base (TCB). A prototype implementation on ARMv8 demonstrates substantially lower startup latency and runtime overhead compared to state-of-the-art solutions, all while maintaining a minimal TCB.

Abstract

The rapid advancement of cloud-native technologies has created an urgent need for security. Currently, confidential containers are increasingly deployed in multi-tenant environments. Existing confidential container designs mainly adopt a microVM-based architecture. Although this approach improves inter-container isolation, its complex software stack leads to high startup latency and significant resource overhead, making it unsuitable for short-lived container workloads. In this paper, we propose Fasco, a lightweight confidential container runtime based on the ARM Confidential Compute Architecture (CCA). Fasco directly instantiates each container as an independent Container Realm, leveraging CCA's hardware-enforced isolation to ensure the confidentiality and integrity of application data inside the container. In addition, Fasco introduces a dedicated System Realm to provide system services and resource management for container realms. Through exception forwarding and shared buffers, Fasco ensures isolation among different container realms. We have implemented a prototype of Fasco and evaluated its performance on ARMv8 hardware. Experimental results show that Fasco reduces the startup latency and performance overhead of existing confidential container architectures while maintaining a small TCB.

Problem

• confidential containers
• microVM
• startup latency
• resource overhead
• short-lived workloads

Innovation

• Confidential Containers
• ARM CCA
• Lightweight Isolation
• Container Realm
• Trusted Computing Base