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Cybersecurity · head to head

Cosign vs Diligent

Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
Diligent logo

Diligent

Cybersecurity

Board management and enterprise GRC platform assembled from Galvanize, Steele and Diligent Boards

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Cosign has a free tier, so it costs nothing to try first.
  • 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.; Diligent the platform is an assembly of acquisitions, with the analytics engine from ACL, risk from Rsam, ethics and third-party diligence from Steele and the board portal from Diligent itself, so cross-module reporting and consistent user experience should be tested in a proof of concept rather than assumed.
  • They diverge on capability: Cosign covers Keyless signing, Diligent covers Diligent Boards.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Diligent actually diverge.

Attributes where Cosign and Diligent differ
AttributeCosignDiligent
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsmacOS, Linux, Windows, DockerWeb, iOS, Android, Windows

Identical on both: 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 Diligent

  • Diligent Boards
  • Entity management
  • Audit and analytics
  • Risk management
  • Third-party risk
  • Ethics and compliance
  • ESG and sustainability
  • Market intelligence

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

Diligent

  • A listed company that wants board papers, entity records and the audit committee reporting pack produced from one governance systemnot Cosign
  • An internal audit function moving from sampling to full-population transaction testing using the ACL heritage analytics enginenot Cosign
  • A regulated firm consolidating a whistleblower hotline, third-party due diligence and policy attestation after an enforcement findingnot Cosign
  • A group needing sustainability disclosure data collected with the same audit trail and controls as financial reportingnot 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.

Diligent

  • The platform is an assembly of acquisitions, with the analytics engine from ACL, risk from Rsam, ethics and third-party diligence from Steele and the board portal from Diligent itself, so cross-module reporting and consistent user experience should be tested in a proof of concept rather than assumed.
  • Pricing is unpublished and consistently at the top of the market, and organisations that need only one capability, a board portal or an audit analytics tool, generally pay less and get more from a specialist.
  • Renewal leverage is weak once the board portal is embedded, because directors are the least willing user group to be migrated and that dependency is well understood by the vendor at renewal time.
  • The analytics engine expects real data skills, and audit teams without an analytics-capable member typically use a fraction of what they licensed while paying for all of it.
  • Module-by-module implementation means the promised single view of governance and risk usually arrives years after the first purchase, if the later modules are ever funded.

Pricing, plan by plan

Cosign

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

Diligent

On request
  • Diligent One Platform$undefined/year
    • Quoted by module and user count
    • Board portal seats priced separately from GRC modules
    • Annual subscription, commonly multi-year

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 Diligent if

  • You need diligent boards.
  • You work on Web, iOS, Android, Windows.
  • You also want entity management.
Diligent review

Questions people ask

Is Cosign or Diligent better?
Neither clearly leads. Cosign starts at Free and Diligent at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Diligent?
Cosign has a free tier; the other does not. Paid plans start at Free for Cosign and On request for Diligent.
Does Cosign or Diligent run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Diligent runs on Web, iOS, Android, Windows.
Can I use Cosign for free?
Yes. Cosign has a free tier, so you can try it without paying. Diligent starts at On request.
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 Diligent is typically brought in for.
What can Cosign do that Diligent cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Diligent covers Diligent Boards, Entity management, Audit and analytics, Risk management.

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.

Diligent: Is Diligent One the same product as Galvanize?

It contains it. Diligent bought Galvanize, the ACL and Rsam merger, for around one billion dollars in April 2021, and its audit analytics and risk modules are that heritage rebranded into Diligent One.

Cosign: Is signing alone enough?

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

Diligent: What does Diligent cost?

Not published. It is quoted by module and user, and board portal seats are priced differently from GRC seats. Expect an annual or multi-year enterprise agreement.

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.

Diligent: Can you buy just the board portal?

Yes, Diligent Boards is sold on its own and is the most common entry point. The GRC modules are separate purchases.

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.

Diligent: Does it replace a SOC 2 automation tool?

No. Diligent is aimed at enterprise audit, risk and governance, not at automated evidence collection for security certifications.

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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