Cosign vs Notation
Cosign
github.comNotation
notaryproject.devSide by side
| Figure | Cosign | Notation |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 1 | 1 |
| Spec score · Code Signing Software | 8.5 (#3) | 7.8 (#11) |
| Intended users | The Sigstore integration guidance identifies open-source package managers as primary stakeholders for artifact signing and verification workflows. | The README describes Notation as usable by developers and CI/CD pipelines to produce portable signatures and store them with signed artifacts in OCI-compliant registries. |
| Purpose | Cosign signs and verifies OCI containers and other software artifacts. | Notation is a command-line tool for signing and verifying artifacts in OCI registries. |
| Support | The project directs users with issues to open a GitHub issue or ask in its Slack channel. | The README directs users to the Notation supported releases information for support details. |
Plans
In their own words
Cosign
Cosign is a free tool for signing and verifying OCI container images and other software artifacts. It can store container signatures in an OCI registry and publish generic artifacts through OCI. Supported targets include blobs, binaries, scripts, configuration files, SBOMs, WASM modules, Tekton bundles, eBPF modules, and in-toto attestations whose payloads use DSSE. Its default keyless workflow uses temporary keys held in memory, short-lived certificates from Sigstore’s Fulcio certificate authority, and entries in the Rekor transparency log. Other signing options include hardware and KMS-backed keys, encrypted keypairs generated by Cosign, and user-provided PKI. Cosign supports CI/CD signing, with guidance for GitHub Actions and GitLab CI/CD. Offline verification is possible when the image and signature materials are available locally and a trusted root is supplied. The project describes Cosign as a legacy signing system and recommends Sigstore-go for verification integrations. Its CLI-focused design has no API stability guarantees, and the documentation does not recommend it for application integration.
Notation
Notation is a command-line tool for signing and verifying container images and other artifacts in OCI registries, including software bills of materials. It implements the Notary Project specifications, which are intended to help secure software supply chains. Its signatures can move between OCI registries and be validated in connected, intermittently connected, or disconnected environments without additional server infrastructure. The specifications define signature envelopes using COSE or JWS. Notation can integrate with existing key management systems through a plugin model, with instructions for Azure Key Vault and AWS Signer. Developers and CI/CD pipelines can create signatures and store them alongside signed artifacts. The project provides a quick start for signing and validating a container image. Notation runs on Linux, macOS, and Windows and is free under the Apache 2.0 license. Cloud signing, trusted timestamping, and CI/CD signing are listed capabilities; a certificate is not provided. The specifications repository lists a 2023 security audit, and the project overview describes continuous fuzz testing across three repositories.