Frequently Asked Questions (original) (raw)

Last updated: January 23, 2025

General Questions

What is the Chrome Root Store?

Chrome uses digital certificates (often referred to as “certificates,” “HTTPS certificates,” or “server authentication certificates”) to ensure the connections it makes on behalf of its users are secure and private. Certificates bind a domain name to a public key, which Chrome uses to encrypt data sent to and from the corresponding website.

As part of establishing a secure connection to a website, Chrome verifies that a recognized system known as a “Certification Authority” (CA) issued its certificate. Certificates issued by a CA not recognized by Chrome or a user’s local settings can cause users to see warnings and error pages.

Root stores, sometimes called “trust stores,” tell operating systems and applications what certificates to trust.

The Chrome Root Store contains the set of certificates Chrome trusts by default.

What is the Chrome Certificate Verifier?

Historically, Chrome integrated certificate verification processes with the platform it ran on. This resulted in inconsistent user experiences across platforms, making it difficult for developers to understand Chrome's expected behavior.

The launch of the Chrome Certificate Verifier addressed these concerns by applying a common certificate verification process across Windows, macOS, Chrome OS, Linux, and Android.

Note: Apple policies prevent the Chrome Certificate Verifier and corresponding Chrome Root Store from being used on Chrome for iOS.

When did these features land?

The Chrome Root Store and Chrome Certificate Verifier were rolled out to Chrome users as described below.

Chrome on...*	Rollout Began**	Enabled by Default
Android	Chrome 114	Chrome 115
Chrome OS	Chrome 114	Chrome 114
iOS***	N/A	N/A
Linux	Chrome 114	Chrome 114
macOS	Chrome 105	Chrome 108
Windows	Chrome 105	Chrome 108

Notes:
(*) Find Chrome browser system requirements here.

(**) During this release, users also had the opportunity to “opt-in” to these features, regardless of whether they were automatically enrolled in the rollout population.

(***) Apple policies prevent the Chrome Root Store and Chrome Certificate Verifier from being used on Chrome for iOS.

How do these features impact “enterprise”, “private”, or “only-locally trusted” certificates?

Depending on the underlying connection protocol used, the Chrome Certificate Verifier considers locally-managed certificates during the certificate verification process.

How can I apply for my CA's inclusion in the Chrome Root Store?

CA Owners who meet the Chrome Root Program policy requirements may apply for a CA certificate’s inclusion in the Chrome Root Store. CAs included in the Chrome Root Store are expected to adhere to the Chrome Root Program policy and continue to operate in a consistent and trustworthy manner. A CA owner’s failure to follow the requirements defined in the Chrome Root Program policy may result in a CA certificate’s removal from the Chrome Root Store, limitations on Chrome's acceptance of the certificates they issue, or other technical or policy restrictions.

Support and Troubleshooting

Where can I report an issue?

If you believe the Chrome Certificate Verifier is not working as intended, submit a bug and attach a NetLog dump repeating the steps leading to the issue from a new Incognito window. Add a comment to route the bug to the Internals>Network>Certificate component for the fastest delivery to the appropriate triage team.

If you believe you've identified a Security Bug, follow these instructions.

Can I revert to the platform root store and verifier?

An enterprise policy was available for a limited time in support of troubleshooting during the transition to the Chrome Root Store and Chrome Certificate Verifier.

This enterprise policy is now deprecated.

Additional Information for Administrators, Engineers, and Power Users

How is the Chrome Root Store updated?

Chrome uses a “component updater” tool to push specific updates to browser components without updating the Chrome browser application. As root CA certificates are added or removed from the Chrome Root Store, or otherwise modified by the Chrome Root Store, the component updater will automatically propagate these changes to user endpoints without user action.

If your enterprise has disabled component updates, endpoints will only receive updated versions of the Chrome Root Store during Chrome browser application updates.

During routine operating conditions, the Chrome Root Store is updated approximately quarterly. However, aperiodic updates may take place to promote the safety and privacy of Chrome's users.

What happens when a certificate is added to or removed from the Chrome Root Store?

Google Chrome includes or removes self-signed root CA certificates in the Chrome Root Store as it deems appropriate at its sole discretion.

New binary releases of Chrome include the current version of the Chrome Root Store. If there is a change to the Chrome Root Store, future binary releases of Chrome will automatically include that change.

Existing versions of Chrome relying on the Chrome Root Store and capable of receiving component updates typically receive updated versions of the Chrome Root Store within 24-hours of the component’s release. Upon receiving the updated component, Chrome will rely on the contents of the updated root store.

Existing versions of Chrome not relying on the Chrome Root Store and/or that have disabled component updates will not become aware of the change(s) until installing a binary update following the publication of the updated root store.

How does the Chrome Certificate Verifier consider local trust decisions?

For TLS connections relying on the Transmission Control Protocol (TCP), the Chrome Certificate Verifier considers local trust decisions for both adding and removing trust. Learn more here.

For TLS connections relying on the Quick UDP Internet Connections (QUIC) protocol, the Chrome Certificate Verifier only considers local trust decisions for removing trust.

How does the Chrome Certificate Verifier integrate with platform trust stores for local trust decisions?

On Windows, the Chrome Certificate Verifier automatically consumes certificates added to the following certificate stores:

Local Machine (accessed via certlm.msc)
- Trust:
  * Trusted Root Certification Authorities
  * Trusted People
  * Enterprise Trust -> Enterprise -> Trusted Root Certification Authorities
  * Enterprise Trust -> Enterprise -> Trusted People
  * Enterprise Trust -> Group Policy -> Trusted Root Certification Authorities
  * Enterprise Trust -> Group Policy -> Trusted People
- Distrust:
  * Untrusted Certificates
  * Enterprise Trust -> Enterprise -> Untrusted Certificates
  * Enterprise Trust -> Group Policy -> Untrusted Certificates
Current User (accessed via certmgr.msc)
- Trust:
  * Trusted Root Certification Authorities
  * Enterprise Trust -> Group Policy -> Trusted Root Certification Authorities
- Distrust:
  * Untrusted Certificates
  * Enterprise Trust -> Group Policy -> Untrusted Certificates

On macOS, the Chrome Certificate Verifier automatically consumes certificates added to the following certificate stores:

Default and System Keychains
- Trust:
  * Any certificate where the “When using this certificate” flag is set to “Always Trust” or
  * Any certificate where the “Secure Sockets Layer (SSL)” flag is set to “Always Trust.”
- Distrust:
  * Any certificate where the “When using this certificate” flag is set to “Never Trust” or
  * Any certificate where the “Secure Sockets Layer (SSL)” flag is set to “Never Trust.”

Note: The Chrome Certificate Verifier does not rely on the contents of the default trust store shipped by the platform provider. When viewing the contents of a platform trust store, it‘s important to remember there’s a difference between an enterprise or user explicitly distributing trust for a certificate and inheriting that trust from the default platform root store. For example, on Windows, viewing the Trusted Root Certification Authorities trust store may present a specific CA certificate as trusted, but that certificate's trust is inherited from the Windows Certificate Trust List, observed by viewing the Trusted Root Certification Authorities\Third-Party trust store, rather than explicitly being distributed as trusted by an enterprise or user (observed in either of the Trusted Root Certification Authorities\Registry, Trusted Root Certification Authorities\Group Policy, or Trusted Root Certification Authorities\Enterprise trust stores).

What about client authentication certificates?

Historically, Chrome has integrated with platform certificate stores to support the use of client authentication certificates. This behavior is unchanged by the rollout of the Chrome Root Store and the Chrome Certificate Verifier.

How can I tell which certificates are trusted by the Chrome Root Store?

The most recent version of the Chrome Root Store is available here.

The Chrome Root Store is updated by Component Updater. To observe the contents of the Chrome Root Store in use by a version of Chrome:

Navigate to chrome://system
Click the Expand... button next to chrome_root_store
The contents of the Chrome Root Store will display

What does it mean for a certificate in the Chrome Root Store to be constrained?

Chrome maintains a variety of mechanisms to protect its users from certificates that put their safety and privacy at risk. One way this is accomplished is through the use of metadata-based constraints added to CA certificates included in the Chrome Root Store.

The set of constraints that may be applied to a CA certificate included in the Chrome Root Store is described here.

To understand a constraint applied to a root included in the Chrome Root Store, view the certificate’s entry in root_store.textproto.

What criteria does the Chrome Certificate Verifier use to evaluate certificates?

The Chrome Certificate Verifier applies standard processing to include checking:

the certificate's key usage and extended key usage are consistent with TLS use cases.
the certificate validity period is not in the past or future.
key sizes and algorithms are of known and acceptable quality.
whether mismatched or unknown signature algorithms are included.
that the certificate does not chain to or through a blocked CA.
conformance with RFC 5280.

Chrome applies additional processing rules for certificates chaining to roots included in the Chrome Root Store, such as:

Certificate Transparency enforcement, and
maximum certificate validity enforcement as required by the CA/B Forum Baseline Requirements (i.e., 398 days or less).

What criteria does the Chrome Certificate Verifier use to build certificate paths?

The Chrome Certificate Verifier was designed to follow path-building guidance established in RFC 4158.

Where is the Chrome Root Store source code located?

Source locations include //net/data/ssl/chrome_root_store, //net/cert, //services/cert_verifier, and //chrome/browser/component_updater/.

Where is the Chrome Certificate Verifier source code located?

Source locations include //net/cert, //net/cert/internal, and //net/cert/pki.