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Cybersecurity · head to head

Cosign vs Keygen

Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
Keygen logo

Keygen

Cybersecurity

Open, source-available software licensing API

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.; Keygen specific Active Licensed User (ALU) pricing not listed; requires interactive pricing calculator
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Keygen actually diverge.

Attributes where Cosign and Keygen differ
AttributeCosignKeygen
Pricing modelOpen source, no licence feeusage-based
PlatformsmacOS, Linux, Windows, DockerWeb

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

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 Keygen

Nothing recorded that Cosign does not also cover.

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 Keygen
  • Attaching a signed bill of materials to a release so consumers can verify its provenancenot Keygen
  • Meeting a customer or regulatory requirement for signed artifactsnot Keygen
  • Verifying third-party images before they enter an internal registrynot Keygen

Keygen

  • Software licensing and distributionnot Cosign
  • Product release managementnot Cosign
  • API-based license verificationnot 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.

Keygen

  • Specific Active Licensed User (ALU) pricing not listed; requires interactive pricing calculator
  • Whitelabel API add-on costs $995/year per domain

Pricing, plan by plan

Cosign

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

Keygen

Free
  • DevFree
    • Up to 100 Active Licensed Users
    • 10 product releases
    • Core licensing API only
  • Std$null/month
    • Scaling with licensing volume
    • Distribution API (OCI/Docker, npm, Rubygems, PyPI, Tauri)
    • Flat monthly/yearly fees
  • Enterprise$null/month
    • Audit logs
    • SAML/SSO
    • IP filtering

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 Keygen if

  • You want to start without paying.
Keygen review

Questions people ask

Is Cosign or Keygen better?
Neither clearly leads. Cosign starts at Free and Keygen at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Keygen?
Cosign starts at Free and Keygen at Free.
Does Cosign or Keygen run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Keygen runs on Web.
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 Keygen is typically brought in for.
What can Cosign do that Keygen cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations.

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.

Keygen: Does Keygen have a free tier?

Yes, the Dev tier is free and supports up to 100 Active Licensed Users with 10 product releases and core licensing API access.

Source
Cosign: Is signing alone enough?

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

Keygen: How is Keygen pricing calculated?

Keygen uses scalable, flat monthly or yearly fees based on your licensing volume (Active Licensed Users). No revenue share or transaction fees are charged.

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.

Keygen: Does Keygen charge for additional features like SSO?

SAML/SSO is included in Enterprise tiers. Whitelabel API support costs $995/year per domain. Premium Support SLA is $995/month for Enterprise.

Source
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.

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