Certificate Trust Store on iPhone, iPad, Mac
The Trust Store is a component of the Apple implementations of security, encryption, and distributed authentication.
The trust store is part of Apple operating systems, and the contents of the Trust Store are (in longstanding practice) common across iPhone, iPad, and Mac.
Being part of the operating system, the trust store cannot be modified by end-users or third-party apps. This is same protection against modifications as provided for the many other similarly-protected parts of the Apple-installed operating system environment.
How does the trust store work? Certificates presented to the operating system. These certificates can be presented to the operating system by individuals and apps. These certificates identify a server or app or individual person. Each certificate is then mathematically compared with the public root certificates present in the Apple Trust Store, and the candidate certificate is determined to be either trusted, or not. Certificates that do not correctly trace back to one of the root certificates, or that are expired or otherwise mismatched will be considered untrusted.
Here is an illustrative example of how public key cryptography works more generally, explained as if this technology were then known and being implemented back in 1939: https://shkspr.mobi/blog/2025/07/it-is-1939-and-you-want-to-use-public-key-cryptography/
How and when is the trust store modified? Apple updates the contents of the trust store when necessary. Not on any particular schedule. If a certificate authority vendor has not been added or removed, and if existing root certificates need no changes, then there is no need to alter and re-publish and re-ship the trust store. Apps and users cannot modify the trust store.
When an update to the trust store is needed, the trust store update then ships with the next associated operating system releases, and continues to be part of subsequent releases until the next trust store update. Apps and users cannot modify the trust store.
The trust store is protected against modifications just like any other part of iOS, iPadOS, or macOS
Recent Root Store versions
2026040100 is used in iOS and iPadOS 26.5, and (presumably) macOS 26.5.
2025082000 is used in iOS and iPadOS 26 through (at least) 26.3.1, and in macOS 26 and following.
2025031200 is the trust store for iOS 18.5, iPadOS 18.5, and macOS 15.5.
2025022600 is the trust store with iOS 18.4, iPadOS 18.4, and macOS 15.4.
2024051501 is the current trust store for iOS 18.3.2, iPadOS 18.3.2, and macOS 15.3.2.
The Trust Store Contents
As an example, here are the certificates associated with the 2024040500 trust store version (note: 00, not 01), directly from what Apple uses to build the trust store:
Here is the asset version showing the 2024040500 asset version number (again note this is the base build 00, not the 01 update):
For comparison, here is 2025022600:
Here is the path to the referenced GitHub source code directly available from and documented on the main Apple website:
https://opensource.apple.com/releases/
Apple Trust Store Version Format
Per Apple: “The trust store version is a number in the format YYYYMMDDNN, where YYYY is the year, MM is the month, DD is the day, and NN is the build number. By convention, NN=00 for base builds that will ship with an OS release, and a non-zero value for asset builds that ship as a standalone update. For example, 2015011900 indicates the trust store contents were changed on 19 Jan 2015, and this is a base build. If the trust store is being produced as a standalone update, this could be 2015011901 instead.”
Apple has a support document related to the trust store, though this support document can tend to be out of date:
Available root certificates for Apple operating systems - Apple Support
Manually Managing the Trust Store (using profiles)
Information on manually managing the trusted certificates:
Updating the Certificate Trust Store on macOS - Apple Community
Self-Signed Root Certificates
When adding a self-signed private certificate authority via MDM profile, the root certificate must be SHA-2 or better, use DNS in the Subject Alternative Name, use 2048-bit or larger keys, and with a lifetime of 825 days or fewer, per Apple: