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Cybersecurity · head to head

BigID vs Cosign

BigID logo

BigID

Cybersecurity

Data discovery and classification across cloud, on-premise and unstructured stores

From
On request
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

  • Only Cosign has a free tier, so it costs nothing to try first.
  • Each has a real cost: BigID pricing scales with data sources and volume, so the cost rises exactly as the estate you need to scan grows, and the modules shown in a demo, including AI security posture and headless deployment, are frequently separate licences that appear only in the final quote.; 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: BigID covers Structured and unstructured scanning, Cosign covers Keyless signing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which BigID and Cosign actually diverge.

Attributes where BigID and Cosign differ
AttributeBigIDCosign
Starting priceOn requestFree
Pricing modelquoteOpen source, no licence fee
Free tierNoYes
PlatformsWeb, API, Self-hostedmacOS, Linux, Windows, Docker

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 BigID

  • Structured and unstructured scanning
  • Identity correlation
  • Data security posture management
  • Access intelligence
  • Privacy request support
  • Retention and minimisation
  • AI data controls
  • Policy and remediation workflow

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.

BigID

  • A bank that has to prove which of thirty year old file shares contain customer identifiers before a data centre migrationnot Cosign
  • A privacy team that cannot fulfil deletion requests because nobody knows which unstructured stores hold a given customer’s recordsnot Cosign
  • A security team wanting to find sensitive data sitting in publicly readable object storage buckets before an attacker doesnot Cosign
  • A company building retrieval augmented AI that must exclude regulated personal data from the index it feeds to a modelnot Cosign

Cosign

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

Where each one falls short

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

BigID

  • Pricing scales with data sources and volume, so the cost rises exactly as the estate you need to scan grows, and the modules shown in a demo, including AI security posture and headless deployment, are frequently separate licences that appear only in the final quote.
  • Scanning large unstructured estates is slow and computationally expensive, so most organisations sample rather than scan everything, which reintroduces uncertainty into the very question they bought the tool to settle.
  • Classification accuracy on messy unstructured content requires tuning, and out of the box false positives on things like reference numbers create a large triage backlog that a small governance team cannot clear.
  • It discovers and reports but does not remediate, so realising value requires a separate process and often separate tooling to actually delete, restrict or move the data it flags.
  • It is built for large enterprises and both the price and the administrative overhead are disproportionate below a few thousand employees, where a lighter DSPM tool covers the security use case for far less.

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

BigID

On request
  • BigID Platform$undefined/year
    • Priced by number of data sources and data volume
    • Discovery and classification core
    • Optional DSPM, access intelligence and AI security modules licensed separately

Cosign

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

Which should you pick?

Choose BigID if

  • You need structured and unstructured scanning.
  • You work on Web, API, Self-hosted.
  • You also want identity correlation.
BigID 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 BigID or Cosign better?
Neither clearly leads. BigID starts at On request and Cosign at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, BigID or Cosign?
Cosign has a free tier; the other does not. Paid plans start at On request for BigID and Free for Cosign.
Does BigID or Cosign run on more platforms?
BigID runs on Web, API, Self-hosted. Cosign runs on macOS, Linux, Windows, Docker.
Can I use Cosign for free?
Yes. Cosign has a free tier, so you can try it without paying. BigID starts at On request.
What is BigID best used for?
BigID is most often used for a bank that has to prove which of thirty year old file shares contain customer identifiers before a data centre migration, a privacy team that cannot fulfil deletion requests because nobody knows which unstructured stores hold a given customer’s records, a security team wanting to find sensitive data sitting in publicly readable object storage buckets before an attacker does, a company building retrieval augmented ai that must exclude regulated personal data from the index it feeds to a model. Of those, a bank that has to prove which of thirty year old file shares contain customer identifiers before a data centre migration and a privacy team that cannot fulfil deletion requests because nobody knows which unstructured stores hold a given customer’s records are not what Cosign is typically brought in for.
What can BigID do that Cosign cannot?
BigID covers Structured and unstructured scanning, Identity correlation, Data security posture management, Access intelligence. Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations.

Answered from the vendors’ own pages

BigID: What does BigID cost?

It is quoted by data source count and volume. Reported contracts run from roughly 15,000 to 175,000 US dollars a year, and add-on modules such as AI security posture are licensed on top.

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.

BigID: Does it handle unstructured data?

Yes, and that is its main advantage. It classifies data in files and shares and correlates findings back to individuals, not just to data types.

Cosign: Is signing alone enough?

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

BigID: Will it delete the data it finds?

Not by itself in most deployments. It identifies and routes findings; deletion and remediation happen through your own processes or connected systems.

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.

BigID: Is it a privacy tool or a security tool?

Both are sold from the same discovery core. Buyers increasingly come from security wanting data security posture management rather than from legal wanting privacy.

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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