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Cybersecurity · head to head

Cosign vs TunnelBear

Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
T

TunnelBear

Cybersecurity

Consumer VPN with a limited free tier and a bear-themed, beginner-friendly app

From
Free
Rated
-
Full reviewWebsite

The short version

  • 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.; TunnelBear free plan's data cap is small compared to competitors offering more generous free allowances.
  • They diverge on capability: Cosign covers Keyless signing, TunnelBear covers Encrypted VPN tunnel.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and TunnelBear actually diverge.

Attributes where Cosign and TunnelBear differ
AttributeCosignTunnelBear
Pricing modelOpen source, no licence feefreemium
PlatformsmacOS, Linux, Windows, Dockerwindows, mac, linux, ios, android

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 Cosign

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

Only in TunnelBear

  • Encrypted VPN tunnel
  • Server location switching
  • GhostBear obfuscation
  • Browser extensions
  • Teams account 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 TunnelBear
  • Attaching a signed bill of materials to a release so consumers can verify its provenancenot TunnelBear
  • Meeting a customer or regulatory requirement for signed artifactsnot TunnelBear
  • Verifying third-party images before they enter an internal registrynot TunnelBear

TunnelBear

  • Casual browsing protection on public Wi-Finot Cosign
  • Occasional geo-unblocking with a light free allowancenot Cosign
  • Bypassing network-level VPN blocking via obfuscationnot Cosign
  • Managing VPN access for a small team with centralized billingnot 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.

TunnelBear

  • Free plan's data cap is small compared to competitors offering more generous free allowances.
  • Lacks advanced features like dedicated IP addresses or split-tunneling controls found in some rival VPNs.
  • Server network is smaller than large competitors like NordVPN or ExpressVPN.
  • No standalone router-level app, limiting whole-network protection options.

Pricing, plan by plan

Cosign

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

TunnelBear

Free
  • FreeFree
    • 2GB of data per month
    • Access to VPN servers
    • Unlimited devices
  • Unlimited$9.99/month
    • Unlimited monthly data
    • All server locations
    • Cheaper on annual/3-year billing
  • Teams$undefined/month
    • Unlimited data
    • 5 connected devices per user
    • Dedicated account manager

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 TunnelBear if

  • You need encrypted vpn tunnel.
  • You want to start without paying.
  • You work on windows, mac, linux, ios, android.
  • You also want server location switching.
TunnelBear review

Questions people ask

Is Cosign or TunnelBear better?
Neither clearly leads. Cosign starts at Free and TunnelBear at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or TunnelBear?
Cosign starts at Free and TunnelBear at Free.
Does Cosign or TunnelBear run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. TunnelBear runs on windows, mac, linux, ios, android.
Can I use Cosign for free?
Both have a free tier, so you can try either at no cost before committing.
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 TunnelBear is typically brought in for.
What can Cosign do that TunnelBear cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. TunnelBear covers Encrypted VPN tunnel, Server location switching, GhostBear obfuscation, Browser extensions.

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.

Cosign: Is signing alone enough?

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

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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