July 2023 Summaries

This article discusses how to use Sigstore and Gitsign with Buildkite OpenID Connect (OIDC) to sign commits created as part of automation flows, making it possible to prove which Buildkite pipeline created a commit. It explains why signing Git commits is important for validating the identity of the signer and reducing the risk of unauthorized code changes. The article also provides a toolkit consisting of OIDC, Sigstore, and Gitsign, along with detailed instructions on how to sign commits in Buildkite. Finally, it emphasizes the importance of cryptographically signing automatically generated Git commits for increased security and traceability in software supply chains.

Utilizing cryptographic signatures for Git commits in automated workflows enhances security and traceability within software development processes. This approach is exemplified by integrating Sigstore and Gitsign with Buildkite OpenID Connect (OIDC) to sign commits made by automation, ensuring developers and downstream processes can authenticate the origin and authenticity of changes. The process involves using OIDC tokens as identities to obtain short-lived X.509 certificates, which are then used by Gitsign to sign the commits, thereby reducing risks of unauthorized code changes and reinforcing the security of the software delivery lifecycle. This method is particularly beneficial in scenarios like scheduled builds and GitOps workflows, where it is crucial to trace commits back to their source pipelines reliably. Despite some limitations in automatic verification by popular platforms like GitHub, which might not recognize Sigstore-generated certificates as verified, manual verification using Gitsign is possible, ensuring only trusted changes are deployed.