Cosign
Command-line tool for Sigstore artifact and container image signatures, with support for keyless signing and SBOM verification.
Technical Architecture & Overview
Cosign is a command-line tool that signs and verifies software artifacts through Sigstore. It adds signatures to container images, binaries, SBOMs, and other artifacts, and can verify those signatures against a transparency log. The tool has a keyless mode that uses short-lived certificates from a Sigstore authority.
Targeted Technical Use Cases
Use Cosign to sign container images and build artifacts in CI/CD, then verify the signatures before deployment.
Evaluation & Trade-offs
Core Strengths
- +Integrates with Sigstore to provide keyless signing and transparency log verification.
- +Signs and verifies OCI-compliant container images and software artifacts.
- +Can be run in CI/CD pipelines and Kubernetes admission controllers.
Trade-Offs & Limitations
- -Requires trust in a Sigstore certificate authority and transparency log.
- -Signature verification must be enforced by the consuming registry or cluster to have effect.
Defensive Security Application
Use Cosign to sign build artifacts and container images, then enforce signature verification to prevent untrusted software from running.
Frequently Asked Questions
What is Cosign?→
Cosign is a command-line tool that signs and verifies software artifacts through Sigstore. It adds signatures to container images, binaries, SBOMs, and other artifacts, and can verify those signatures against a transparency log. The tool has a keyless mode that uses short-lived certificates from a Sigstore authority.
What is Cosign used for?→
Use Cosign to sign container images and build artifacts in CI/CD, then verify the signatures before deployment.
What are the strengths of Cosign?→
- +Integrates with Sigstore to provide keyless signing and transparency log verification.
- +Signs and verifies OCI-compliant container images and software artifacts.
- +Can be run in CI/CD pipelines and Kubernetes admission controllers.
What are the limitations of Cosign?→
- +Requires trust in a Sigstore certificate authority and transparency log.
- +Signature verification must be enforced by the consuming registry or cluster to have effect.
How is Cosign used defensively?→
Use Cosign to sign build artifacts and container images, then enforce signature verification to prevent untrusted software from running.