Softwr

Cybersecurity · head to head

Cosign vs Sysdig

Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
Sysdig logo

Sysdig

Cybersecurity

Cloud-native runtime security platform with real-time detection and response

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.; Sysdig custom pricing requires sales contact, difficult to compare costs
  • They diverge on capability: Cosign covers Keyless signing, Sysdig covers Real-time threat detection and response.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Sysdig actually diverge.

Attributes where Cosign and Sysdig differ
AttributeCosignSysdig
Starting priceFreeOn request
Pricing modelOpen source, no licence feeCustom pricing based on number of hosts, events processed, or time series data
Free tierYesNo
PlatformsmacOS, Linux, Windows, DockerKubernetes, Docker, AWS, GCP, Azure, Cloud-native
FoundedUnknown2013

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 Sysdig

  • Real-time threat detection and response
  • Runtime intelligence
  • AI-powered security agents
  • Vulnerability management
  • Cloud Security Posture Management
  • Container and Kubernetes security
  • Infrastructure as Code security
  • Cloud Infrastructure Entitlement Management

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

Sysdig

  • Real-time threat detection in Kubernetes clustersnot Cosign
  • Container workload vulnerability prioritizationnot Cosign
  • Cloud security posture compliance monitoringnot Cosign
  • Infrastructure entitlement and permission analysisnot Cosign
  • AI workload security and threat remediationnot 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.

Sysdig

  • Custom pricing requires sales contact, difficult to compare costs
  • No published pricing tiers or calculator available
  • Primarily focused on cloud-native environments
  • Requires integration with existing SIEM or monitoring tools for full visibility
  • Steep learning curve for runtime security concepts

Pricing, plan by plan

Cosign

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

Sysdig

On request

No published plan breakdown. See the Sysdig 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 Sysdig if

  • You need real-time threat detection and response.
  • You work on Kubernetes, Docker, AWS, GCP, Azure, Cloud-native.
  • You also want runtime intelligence.
Sysdig review

Questions people ask

Is Cosign or Sysdig better?
Neither clearly leads. Cosign starts at Free and Sysdig at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Sysdig?
Cosign has a free tier; the other does not. Paid plans start at Free for Cosign and On request for Sysdig.
Does Cosign or Sysdig run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Sysdig runs on Kubernetes, Docker, AWS, GCP, Azure, Cloud-native.
Can I use Cosign for free?
Yes. Cosign has a free tier, so you can try it without paying. Sysdig 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 Sysdig is typically brought in for.
What can Cosign do that Sysdig cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Sysdig covers Real-time threat detection and response, Runtime intelligence, AI-powered security agents, Vulnerability 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.

Sysdig: How does Sysdig achieve real-time threat detection?

Sysdig uses runtime intelligence with kernel-level system visibility, capturing live system calls to detect threats at machine speed, typically within 2 seconds.

Source
Cosign: Is signing alone enough?

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

Sysdig: What is runtime intelligence and how does it differ from configuration-based security?

Runtime intelligence reveals what is actually executing in cloud environments through kernel-level visibility, rather than relying on theoretical risks from configuration analysis alone.

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.

Sysdig: What cloud platforms does Sysdig support?

Sysdig supports AWS, GCP, Azure, and IBM Cloud with multiple regional data centers across US, EU, and other regions.

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.

Sysdig: Does Sysdig integrate with existing security tools?

Yes, Sysdig integrates with existing SIEM and monitoring tools to provide unified security visibility across cloud infrastructure.

Source
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 Sysdig

Keep looking

Other head to heads