Softwr

Cybersecurity · head to head

Cosign vs Crossplane

Cosign logo

Cosign

Cybersecurity

Signs and verifies container images and artifacts, with or without managing keys

From
Free
Rated
-
Full reviewWebsite
Crossplane logo

Crossplane

Cloud

The Cloud-Native Framework for Platform Engineering

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Cosign keyless signing inherits every weakness of the identity provider behind it. Sigstore’s own threat model states that if an identity provider is compromised, Sigstore will issue certificates to those identities, so a compromised account produces perfectly valid signatures.; Crossplane requires Kubernetes expertise and infrastructure
  • They diverge on capability: Cosign covers Keyless signing, Crossplane covers Kubernetes extension.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Crossplane actually diverge.

Attributes where Cosign and Crossplane differ
AttributeCosignCrossplane
Pricing modelOpen source, no licence feeUnknown
PlatformsmacOS, Linux, Windows, DockerKubernetes, AWS, Azure, GCP
CategoryCybersecurityCloud

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Cosign

  • Keyless signing
  • Key and KMS signing
  • Registry-native storage
  • In-toto attestations
  • Offline verification
  • Trusted root and signing config

Only in Crossplane

  • Kubernetes extension
  • Custom API building
  • Resource management anywhere
  • Declarative interfaces
  • Component library
  • Provider ecosystem

What people use each for

The jobs each tool is most often brought in to do.

Cosign

  • Signing container images in a build pipeline without managing long-lived private keysnot Crossplane
  • Attaching a signed bill of materials to a release so consumers can verify its provenancenot Crossplane
  • Meeting a customer or regulatory requirement for signed artifactsnot Crossplane
  • Verifying third-party images before they enter an internal registrynot Crossplane

Crossplane

  • Building platform-as-a-service offerings for internal teamsnot Cosign
  • Creating unified control layers for multi-cloud infrastructurenot Cosign
  • Designing declarative APIs for infrastructure provisioningnot Cosign

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Cosign

  • Keyless signing inherits every weakness of the identity provider behind it. Sigstore’s own threat model states that if an identity provider is compromised, Sigstore will issue certificates to those identities, so a compromised account produces perfectly valid signatures.
  • A signature proves who signed, never whether they should have. The documentation is explicit that Sigstore cannot determine authorisation, so every consumer must write and maintain their own identity and issuer policy or verification means nothing.
  • Nothing is enforced without an admission controller. Signing changes what you can prove, not what runs, and the official policy controller has a small maintainer base for a component sitting in a cluster admission path.
  • Upgrades break pipelines. Version 3 changed defaults, version 4 is announced as removing legacy functionality and roughly half the command line flags, and two official client libraries still lacked support for the new log format as of mid 2026.
  • Signatures do not expire. An artifact signed before a maintainer account was compromised and one signed after are indistinguishable unless somebody is actively monitoring the transparency log, and almost nobody is.

Crossplane

  • Requires Kubernetes expertise and infrastructure
  • Steep learning curve for teams new to Kubernetes patterns
  • Provider ecosystem smaller than Terraform

Pricing, plan by plan

Cosign

Free
  • CosignFree
    • Apache-2.0
    • Public Sigstore infrastructure free to use
    • No usage limits published

Crossplane

Free

No published plan breakdown. See the Crossplane review.

Which should you pick?

Choose Cosign if

  • You need keyless signing.
  • You want to start without paying.
  • You work on macOS, Linux, Windows, Docker.
  • You also want key and kms signing.
Cosign review

Choose Crossplane if

  • You need kubernetes extension.
  • You want to start without paying.
  • You work on Kubernetes, AWS, Azure, GCP.
  • You also want custom api building.
Crossplane review

Questions people ask

Is Cosign or Crossplane better?
Neither clearly leads. Cosign starts at Free and Crossplane at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Crossplane?
Cosign starts at Free and Crossplane at Free.
Does Cosign or Crossplane run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Crossplane runs on Kubernetes, AWS, Azure, GCP.
Can I use Cosign for free?
Both have a free tier, so you can try either at no cost before committing.
What is Cosign best used for?
Cosign is most often used for signing container images in a build pipeline without managing long-lived private keys, attaching a signed bill of materials to a release so consumers can verify its provenance, meeting a customer or regulatory requirement for signed artifacts, verifying third-party images before they enter an internal registry. Of those, signing container images in a build pipeline without managing long-lived private keys and attaching a signed bill of materials to a release so consumers can verify its provenance are not what Crossplane is typically brought in for.
What can Cosign do that Crossplane cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Crossplane covers Kubernetes extension, Custom API building, Resource management anywhere, Declarative interfaces.

Answered from the vendors’ own pages

Cosign: Does Cosign tell me if an image is vulnerable?

No. It has no vulnerability knowledge whatsoever. It can carry an SBOM as a signed attestation but never reads it. Pair it with a scanner.

Crossplane: Is Crossplane free?

Yes, Crossplane is open source and free to use. It requires a Kubernetes cluster but has no licensing costs.

Source
Cosign: Is signing alone enough?

No. Verification is a command somebody runs. Without an admission controller enforcing it, an unsigned image still runs.

Crossplane: What is Crossplane used for?

Crossplane is used to build control planes and platforms for infrastructure management, enabling platform teams to expose safe APIs to other teams.

Source
Cosign: What does a bare cosign verify actually prove?

Very little. Without a pinned certificate identity and OIDC issuer, it accepts a valid signature from any identity at all.

Cosign: What is the risk of keyless signing?

Your OIDC provider becomes the root of trust. Compromise of that account yields genuine, verifiable signatures, so account security is the control that matters.

Cosign: Should we expect breaking changes?

Yes. Version 4 is announced to remove roughly half the flags, and a post-quantum migration is named as a further breaking change after that.

Share

Related pages

More on Cosign

More on Crossplane

Keep looking

Other head to heads