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Trust Stores

This is a high-level overview of trust stores (also called certificate stores) and a list of commonly used trust stores and settings.

What is a trust store?

There are millions of identity certificates issued to people and devices around the world. Certificates constantly change as some are revoked and others are issued—far too many for your computer to maintain an up-to-date list.

Instead, a trust store (a list of trusted root certificates) is maintained. When you are presented with a person or device certificate from a PIV credential, website, email, or some other digital item, your operating system or application will check to see whether the certificate has a valid path to one of the trusted root certificates in its trust store.

What are the most commonly used trust stores?

Operating systems, browsers, and some commercial software use trust stores to verify whether a certificate with which you are being presented should be trusted.

Here are some common trust stores. If the Federal Common Policy CA (FCPCA) (i.e., COMMON) root certificate is included in a trust store and distributed by default, the Includes FCPCA (COMMON)? column below will say Yes.

The Federal Common Policy CA root certificate will be removed from the Microsoft trust store. It has already been removed from the Apple trust store. Please see the Announcements for more informations and Solutions sections for mitigation actions that you should take as soon as possible.

Trust Store Includes FCPCA
Trust Store Manager Platforms Serviced Program Information Location
Microsoft Trusted Root Certificate Program Yes (COMMON removal pending) Microsoft Management Console Windows OS, Internet Explorer Browser, Outlook http://aka.ms/RootCert
Apple Root Certificate Program No Keychain Access Utility macOS, iOS, tvOS, WatchOS, Safari Browser https://www.apple.com/certificateauthority/ca_program.html
Mozilla Network Security Services (NSS) No Browser trust store Firefox, Thunderbird, Linux Operating Systems https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/
Adobe Approved Trust List Yes Application trust store Adobe Acrobat https://helpx.adobe.com/acrobat/kb/approved-trust-list2.html
Java Root Certificate Program No Java Applet Java Distributions http://www.oracle.com/technetwork/java/javase/javasecarootcertsprogram-1876540.html
Google No Google Admin Console Android OS, Chromium OS https://www.chromium.org/Home/chromium-security/root-ca-policy
Opera Uses Mozilla      

Google Chrome uses the trust store of the operating system on Microsoft, Apple, and Android systems. Linux-based systems distribute the Mozilla NSS Library, which may be modified by each version of Linux.

How do I set dynamic path validation for the Microsoft trust store in Windows operating systems?

With dynamic path validation (as opposed to static path validation), the certificate validation libraries will build the certificate chain based on the Authority Information Access (AIA) entry in the certificate.

Dynamic path validation is a registry setting:

  1. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\OID\EncodingType 0\ CertDllCreateCertificateChainEngine\Config
  2. Create a new DWORD entry.
  3. Add MaxAIAUrlRetrievalCertCount as the name.
  4. Set the value to 30.
  5. Reboot your system (required).

All registry settings for managed Federal Government computers should use group policy objects or the automated configuration management tools available in your agency.

How do I see which Federal PKI certificate policies are trusted by Adobe?

Federal PKI certificates may be used for digitally signing documents between federal agencies and with business partners. Adobe is just one option used for digital signatures.

A common question is which certificate policy object identifiers (OIDs) are trusted? To see the certificate policy OIDs trusted by Adobe Acrobat:

  1. Open Adobe Acrobat.
  2. Edit > Preferences > Signatures > Identities & Trusted Certificates > More.
  3. Choose Trusted Certificates from the left-hand sidebar.
  4. Choose Federal Common Policy CA and then the Certificate Details tab.
  5. Choose the Certificate Viewer window, and click the Policies tab to see Policy Restrictions.
  6. In Certificate Policies, you will see a comma-separated list of policy OIDs.

What certificate policy OIDs are included in COMMON?

The certificate policy OIDs defined in the X.509 Certicate Policy for the U.S. Federal PKI Common Policy Framework are:

Certificate Policies                                 OIDs               Certificate Use                                     
Common Hardware                               2.16.840. PIV and Federal Bridge Medium Hardware Token                                    
Federal Bridge Medium Hardware Commercial Best Practice* 2.16.840. Federal Bridge Medium Hardware Token (PKI Trusted Roles may not be U.S. citizens)
Common High                                   2.16.840. High Assurance Policy                                                            
PIV-I Hardware                               2.16.840. PIV-Interoperable                                                                
SHA-1 Hardware                               2.16.840. SHA-1 Medium Hardware Tokens through SHA-1 Federal Root CA