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Cybersecurity · head to head

Proofpoint vs Sigstore

Proofpoint logo

Proofpoint

Cybersecurity

Email security and data protection suite from a private company owned by Thoma Bravo, licensed per user with modules sold separately.

From
$6/month
Rated
-
Full reviewWebsite
Sigstore logo

Sigstore

Cybersecurity

Free public signing and transparency infrastructure for open source artifacts

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Sigstore has a free tier, so it costs nothing to try first.
  • Each has a real cost: Proofpoint licensing is per user per year with each capability as a separate stock item, so the platform shown in a proof of concept is normally several products, and adding awareness training, data loss prevention or insider threat monitoring later is a fresh negotiation rather than enabling a feature.; Sigstore the security model depends on somebody watching the log. The documentation states that compromise of an identity provider or of Fulcio itself is detectable only if third parties monitor the transparency log, the monitoring tool is a community-tier rather than core project, and almost no consumer runs one.
  • They diverge on capability: Proofpoint covers Inline secure email gateway, Sigstore covers Fulcio.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Proofpoint and Sigstore actually diverge.

Attributes where Proofpoint and Sigstore differ
AttributeProofpointSigstore
Starting price$6/monthFree
Pricing modelsubscriptionOpen source, public instance free to use
Free tierNoYes
PlatformsEmail, Cloud, WebWeb, Linux, macOS, Windows, Self-hosted
Founded2002Unknown

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 Proofpoint

  • Inline secure email gateway
  • Attachment sandboxing
  • URL rewriting and click-time analysis
  • Threat Response Auto-Pull
  • Email Fraud Defense
  • Security awareness training
  • Insider Threat Management
  • Enterprise DLP

Only in Sigstore

  • Fulcio
  • Rekor
  • Keyless signing
  • Multi-language clients
  • Timestamp authority
  • Neutral governance

What people use each for

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

Proofpoint

  • A regulated organisation that needs a filtering layer, DMARC enforcement and archiving with an auditable trail across all threenot Sigstore
  • An organisation that suffered a business email compromise and must show its board a control that stops delivery rather than remediating afterwardsnot Sigstore
  • Concentrating stronger controls and training on the specific individuals who actually receive targeted attacks rather than applying uniform policynot Sigstore
  • Retracting a phishing message from thousands of mailboxes after the verdict changes, including copies that were forwarded internallynot Sigstore

Sigstore

  • Open source projects signing releases without running a certificate authoritynot Proofpoint
  • Organisations meeting a signed-artifact requirement without buying a signing productnot Proofpoint
  • Publishing provenance that a consumer can verify independently of younot Proofpoint
  • Self-hosting the same components where a public log is unacceptablenot Proofpoint

Where each one falls short

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

Proofpoint

  • Licensing is per user per year with each capability as a separate stock item, so the platform shown in a proof of concept is normally several products, and adding awareness training, data loss prevention or insider threat monitoring later is a fresh negotiation rather than enabling a feature.
  • It sits inline with MX records pointed at it, so any service degradation is a mail outage for the entire organisation, and both migrating on and migrating off are cutovers with queueing, rollback planning and a real risk of message loss.
  • Most customers on Microsoft 365 E5 or Google Workspace Enterprise are already paying for native filtering, so Proofpoint is a second licence layered over a capability the organisation owns, and that comparison is raised by finance at every single renewal.
  • The administration console carries a decade of acquisitions: the classic gateway policy routes and filters do not share a model with the newer module interfaces, rule evaluation is order-sensitive in ways that surprise untrained administrators, and mistakes there silently change what is delivered.
  • Quarantine management is a standing helpdesk workload because legitimate bulk mail, invoices and supplier notifications are held, and unless end-user digests are configured and users are taught to use them, the security team becomes the mail release desk.

Sigstore

  • The security model depends on somebody watching the log. The documentation states that compromise of an identity provider or of Fulcio itself is detectable only if third parties monitor the transparency log, the monitoring tool is a community-tier rather than core project, and almost no consumer runs one.
  • It is a 99.5 percent objective with no service level agreement, which permits several hours of downtime a month and offers no remedy. A pipeline that signs on every build has taken a hard dependency on a free service with no contract behind it.
  • Log scale is a live engineering problem rather than a theoretical one. The active shard holds billions of entries, the log has already been sharded twice, and sharding version 1 requires stopping traffic, which is why a replacement was built.
  • Ten-minute certificates make trust depend on log availability. Verifying an older signature relies on the log entry proving it was made inside that window, so a lost or unreachable entry can render a valid artifact unverifiable.
  • Migration debt is substantial and ongoing. Version 2 of the log is generally available but not the public default, the signing client has an announced breaking release ahead, some official clients lag the new log format, and a post-quantum migration is named as the next break after that.

Pricing, plan by plan

Proofpoint

$6/month
  • Email Protection$6/month
    • Per user
    • Advanced threat detection
    • Data loss prevention
  • Compliance$8/month
    • All Email Protection
    • Archive & search
    • eDiscovery
  • Advanced Threat$10/month
    • All Compliance features
    • Targeted attack detection
    • Behavior analytics

Sigstore

Free
  • Public good instanceFree
    • Free to everyone with no contract
    • 99.5 percent availability objective, not an agreement
    • 100KB cap per attestation upload
  • Self-hostedFree
    • Apache-2.0
    • Run your own Fulcio and Rekor
    • Rekor v2 available for self-hosters

Which should you pick?

Choose Proofpoint if

  • You need inline secure email gateway.
  • You work on Email, Cloud, Web.
  • You also want attachment sandboxing.
Proofpoint review

Choose Sigstore if

  • You need fulcio.
  • You want to start without paying.
  • You work on Web, Linux, macOS, Windows, Self-hosted.
  • You also want rekor.
Sigstore review

Questions people ask

Is Proofpoint or Sigstore better?
Neither clearly leads. Proofpoint starts at $6/month and Sigstore at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Proofpoint or Sigstore?
Sigstore has a free tier; the other does not. Paid plans start at $6/month for Proofpoint and Free for Sigstore.
Does Proofpoint or Sigstore run on more platforms?
Proofpoint runs on Email, Cloud, Web. Sigstore runs on Web, Linux, macOS, Windows, Self-hosted.
Can I use Sigstore for free?
Yes. Sigstore has a free tier, so you can try it without paying. Proofpoint starts at $6/month.
What is Proofpoint best used for?
Proofpoint is most often used for a regulated organisation that needs a filtering layer, dmarc enforcement and archiving with an auditable trail across all three, an organisation that suffered a business email compromise and must show its board a control that stops delivery rather than remediating afterwards, concentrating stronger controls and training on the specific individuals who actually receive targeted attacks rather than applying uniform policy, retracting a phishing message from thousands of mailboxes after the verdict changes, including copies that were forwarded internally. Of those, a regulated organisation that needs a filtering layer, dmarc enforcement and archiving with an auditable trail across all three and an organisation that suffered a business email compromise and must show its board a control that stops delivery rather than remediating afterwards are not what Sigstore is typically brought in for.
What can Proofpoint do that Sigstore cannot?
Proofpoint covers Inline secure email gateway, Attachment sandboxing, URL rewriting and click-time analysis, Threat Response Auto-Pull. Sigstore covers Fulcio, Rekor, Keyless signing, Multi-language clients.

Answered from the vendors’ own pages

Proofpoint: Does it replace Microsoft Defender for Office 365?

Functionally it overlaps heavily, and running both means paying twice for filtering. Most Proofpoint customers on Microsoft 365 keep Defender licensed because it is bundled in E5 and use Proofpoint as the inline gateway. Expect to justify that duplication annually.

Sigstore: Is the public instance really free?

Yes, with no contract and no paid tier. That is also the weakness: a 99.5 percent objective with no agreement, no remedy and support through Slack.

Proofpoint: Who owns Proofpoint?

Thoma Bravo, a private equity firm, which took the company private in 2021. It has continued to acquire since, including Tessian, Normalyze and Hornetsecurity, which is why the portfolio spans so many adjacent categories.

Sigstore: Has the public log moved to Rekor v2?

No. Version 2 reached general availability in October 2025 and self-hosters can use it, but the public instance still defaults to version 1 and the project has said it will for the foreseeable future.

Proofpoint: Do I have to change my MX records?

For the gateway, yes. That is what makes it inline and able to block before delivery. Some newer capabilities integrate through the mailbox API instead, but the core protection model is MX-level.

Sigstore: Does Sigstore make my dependencies safe?

No, and this is a category error worth avoiding. It tells you who published something. It has no knowledge of what the artifact contains or whether it is vulnerable.

Proofpoint: Is security awareness training included?

No, it is a separate subscription. It integrates well with the threat data, so training can target the users actually being attacked, but it is a distinct line item on the quote.

Sigstore: What are the rate limits?

Not published. Only the 100KB cap per attestation upload is documented, so do not design a high-volume pipeline around assumed throughput.

Proofpoint: What does Threat Response Auto-Pull actually do?

It removes messages from mailboxes after delivery when the verdict changes, including copies that users forwarded internally. It is the answer to the case where a link was clean at delivery and weaponised an hour later.

Sigstore: Should we self-host it?

If a public record of every signature is unacceptable, or if a free service with no agreement cannot sit in your build path, then yes. Otherwise the public instance is what most projects use.

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