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Cybersecurity · head to head

Cosign vs ThetaRay

Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
ThetaRay logo

ThetaRay

Cybersecurity

Unsupervised AI transaction monitoring for cross-border and correspondent banking

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.; ThetaRay unsupervised models are harder to justify to an examiner than explicit rules, and some regulators still expect documented threshold logic, which can force you to run both systems.
  • They diverge on capability: Cosign covers Keyless signing, ThetaRay covers Unsupervised detection.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Cosign and ThetaRay actually diverge.

Attributes where Cosign and ThetaRay differ
AttributeCosignThetaRay
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsmacOS, Linux, Windows, DockerWeb

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 ThetaRay

  • Unsupervised detection
  • Cross-border focus
  • Sanctions screening
  • Alert triage
  • Customer risk scoring
  • Cloud native

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

ThetaRay

  • A correspondent bank that cannot see the ultimate originator and needs behavioural signals rather than counterparty listsnot Cosign
  • A cross-border payments fintech whose rules engine produces more alerts than its compliance team can clearnot Cosign
  • A bank under a regulatory consent order needing demonstrable improvement in detection within a fixed periodnot Cosign
  • A payment institution entering a high-risk corridor where existing thresholds were calibrated on domestic trafficnot 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.

ThetaRay

  • Unsupervised models are harder to justify to an examiner than explicit rules, and some regulators still expect documented threshold logic, which can force you to run both systems.
  • The alert reduction claim depends heavily on your data, so a parallel run is essential and adds months and cost before you can decommission the incumbent.
  • Coverage is strongest in cross-border and correspondent flows; institutions whose risk is domestic retail fraud will find the fit weaker than a general-purpose monitoring platform.
  • It is a smaller vendor than the incumbents, so integration connectors into legacy core banking systems are often bespoke work rather than a supported adapter.
  • Model retraining and tuning are vendor-led, which means changing detection behaviour is a support conversation rather than something your own analysts can do that afternoon.

Pricing, plan by plan

Cosign

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

ThetaRay

On request
  • ThetaRay Sonar$undefined/year
    • Priced by monitored transaction volume and number of monitored entities
    • SaaS on Azure with regional data residency options
    • Parallel run and model tuning included in onboarding

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 ThetaRay if

  • You need unsupervised detection.
  • You also want cross-border focus.
ThetaRay review

Questions people ask

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

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.

ThetaRay: Does it replace a rules engine entirely?

Rarely on day one. Most institutions run it alongside existing rules during a parallel period, and some keep specific regulator-mandated rules permanently.

Cosign: Is signing alone enough?

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

ThetaRay: Where is the data processed?

SaaS runs on Microsoft Azure with regional deployment options, which is the mechanism for meeting data residency conditions in regulated markets.

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.

ThetaRay: Is sanctions screening included?

Screening is available on the same platform but licensed as part of the commercial package rather than bundled by default. Confirm it is in your quote.

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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