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Cybersecurity · head to head

Arnica vs Cosign

Arnica logo

Arnica

Cybersecurity

AI-native application security platform detecting and fixing vulnerabilities across the SDLC

From
Free
Rated
-
Full reviewWebsite
Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Arnica per-identity pricing ($25-$50/person/year) requires tracking active developers; 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.
  • They diverge on capability: Arnica covers AI SAST, Cosign covers Keyless signing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Arnica and Cosign actually diverge.

Attributes where Arnica and Cosign differ
AttributeArnicaCosign
Pricing modelPer-identity subscription with annual discountOpen source, no licence fee
PlatformsWeb, GitHub, IDEmacOS, Linux, Windows, Docker

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 Arnica

  • AI SAST
  • Software Composition Analysis
  • Secrets detection
  • IaC scanning
  • Container scanning
  • SBOM generation
  • Agentic rules
  • Pipelineless integration

Only in Cosign

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

What people use each for

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

Arnica

  • Detecting AI-generated vulnerabilities in Copilot and Cursor suggestionsnot Cosign
  • Finding hardcoded secrets before they reach productionnot Cosign
  • Mapping container vulnerabilities back to source codenot Cosign
  • Generating SBOM for supply chain compliance requirementsnot Cosign
  • Scanning infrastructure-as-code for misconfiguration risksnot Cosign

Cosign

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

Where each one falls short

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

Arnica

  • Per-identity pricing ($25-$50/person/year) requires tracking active developers
  • Overage identity tracking via 90-day PR activity can be unpredictable
  • Free plan limited to weekly updates, requiring upgrade for real-time scanning
  • Advanced add-ons (Image Scanning, AI SAST, Agentic Rules Enforcer) pricing not published
  • On-premises deployment limited to Enterprise tier

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.

Pricing, plan by plan

Arnica

Free
  • FreeFree
    • No credit card required
    • 14-day trial available
    • Weekly risk identification updates
  • Core Business$360/year
    • Monthly billing option at $30/identity/month
    • Annual billing at $25/identity/month (17% discount)
    • Real-time risk scanning and notifications
  • Core Enterprise$720/year
    • Monthly billing option at $60/identity/month
    • Annual billing at $50/identity/month (17% discount)
    • All Core Business features

Cosign

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

Which should you pick?

Choose Arnica if

  • You need ai sast.
  • You want to start without paying.
  • You work on Web, GitHub, IDE.
  • You also want software composition analysis.
Arnica review

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

Questions people ask

Is Arnica or Cosign better?
Neither clearly leads. Arnica starts at Free and Cosign at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Arnica or Cosign?
Arnica starts at Free and Cosign at Free.
Does Arnica or Cosign run on more platforms?
Arnica runs on Web, GitHub, IDE. Cosign runs on macOS, Linux, Windows, Docker.
Can I use Arnica for free?
Both have a free tier, so you can try either at no cost before committing.
What is Arnica best used for?
Arnica is most often used for detecting ai-generated vulnerabilities in copilot and cursor suggestions, finding hardcoded secrets before they reach production, mapping container vulnerabilities back to source code, generating sbom for supply chain compliance requirements. Of those, detecting ai-generated vulnerabilities in copilot and cursor suggestions and finding hardcoded secrets before they reach production are not what Cosign is typically brought in for.
What can Arnica do that Cosign cannot?
Arnica covers AI SAST, Software Composition Analysis, Secrets detection, IaC scanning. Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations.

Answered from the vendors’ own pages

Arnica: How are identities defined in Arnica pricing?

Identities are any users and other contributing entities that contributed code and/or had PR activity during the last 90 days. This ensures billing matches active developers.

Source
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.

Arnica: What is the annual discount?

Annual prepayment offers approximately 17% savings versus monthly billing. Core Business annual is $300/identity versus $360 for monthly.

Source
Cosign: Is signing alone enough?

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

Arnica: Can I cancel or downgrade Arnica anytime?

Yes. Subscriptions can be cancelled or downgraded at any time. Overage identities receive automatic protection with true-up invoicing.

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.

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