Why Should I Trust Your Code?

For Confidential Computing to become ubiquitous in the cloud, in the same way that HTTPS became the default for networking, a different, more flexible approach is needed. Although there is no guarantee that every malicious code behavior will be caught upfront, precise auditability can be guaranteed: Anyone who suspects that trust has been broken by a confidential service should be able to audit any part of its attested code base, including all updates, dependencies, policies, and tools. To achieve this, we propose an architecture to track code provenance and to hold code providers accountable. At its core, a new Code Transparency Service (CTS) maintains a public, append-only ledger that records all code deployed for confidential services. Before registering new code, CTS automatically applies policies to enforce code-integrity properties. For example, it can enforce the use of authorized releases of library dependencies and verify that code has been compiled with specific runtime checks and analyzed by specific tools. These upfront checks prevent common supply-chain attacks.