Cosign vs Red Hat Trusted Artifact Signer

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.

Red Hat Trusted Artifact Signer (RHTAS) helps organizations sign and verify software artifacts, including container images, binaries, documents, source-code commits, software bills of materials, build artifacts, and AI/ML models. Red Hat describes it as an enterprise deployment of Sigstore. Its client tools include cosign, gitsign, and rekor-cli. Signing can use OpenID Connect identities or self-managed keys held in a third-party key management system. A certificate transparency log records signing events in an immutable ledger that Red Hat says is inaccessible to the public. Deployment guidance covers Red Hat OpenShift Container Platform and Red Hat Enterprise Linux; Amazon EKS is listed as a development preview for RHTAS 1.4. The OpenShift guide requires version 4.16 or later, cluster-admin access, an OIDC provider, and the oc command-line tool. CLI binaries are listed for Windows, macOS, and Linux. Pricing is on request, and a 60-day trial is listed. Signing and verifying AI/ML models with the CLI is marked Technology Preview and is not covered by production SLAs.