Source code attestation is the verification that deployed software originates from an authorized source repository and has not been altered by unauthorized changes. It provides cryptographic proof that the code used to build an artifact matches what exists in version control. In secure supply chains, platforms such as Chainguard validate this attestation before allowing deployment.
How It Works
During the build process, a CI system generates a signed attestation that links the built artifact to a specific commit, repository, and build workflow. This attestation typically follows standards such as in-toto or SLSA and is cryptographically signed using trusted keys. The signature binds the artifact digest to its source metadata.
The attestation is stored alongside the artifact in a registry or transparency log. When the artifact is promoted or deployed, a policy engine verifies the signature and checks that the repository, branch, and commit meet defined trust requirements. If the metadata does not match policy, deployment fails.
Chainguard enforces these checks at deployment time. It validates that the image digest corresponds to an approved source, that the build occurred in a trusted environment, and that no tampering occurred between build and runtime.
Why It Matters
Modern pipelines pull dependencies from multiple repositories and rely on automated builds. Without verification, attackers can inject malicious code, compromise build systems, or replace artifacts in registries. Cryptographic proof of origin reduces the risk of <a href="https://aiopscommunity1-g7ccdfagfmgqhma8.southeastasia-01.azurewebsites.net/glossary/digital-supply-chain-security/" title="Digital Supply Chain Security">supply chain attacks and unauthorized modifications.
For operations teams, this control strengthens change management and compliance. It provides auditable evidence that running workloads match approved source code, supporting frameworks such as SOC 2, ISO 27001, and SLSA.
Key Takeaway
Source code attestation ensures that what you deploy is exactly what your trusted repository produced, verified cryptographically and enforced by policy.