mscerts 2026.4.30

Python package for providing Microsoft's CA Bundle.

This package provides easy access to the Root Certificate Authorities present in the Microsoft Trusted Root Program. It is a fork of Kenneth Reitz’s certifi project, which provides access to Mozilla’s collection of Root Certificates.

Warning: Microsoft’s CA Program allows granular CA deprecation, which is not properly supported by certificate bundle files. This means that using this bundle may result in improper trust being applied, e.g. trusting certificates that are not actually trusted in their current use.

It is therefore highly recommended to use certifi instead for almost all needs, except in cases where the Microsoft store is specifically required, such as in the signify project.

Installation

mscerts is available on PyPI. Simply install it with pip:

$ pip install mscerts

Usage

To reference the installed certificate authority (CA) bundle, you can use the built-in function:

>>> import mscerts

>>> mscerts.where()
'/usr/local/lib/python3.7/site-packages/mscerts/cacert.pem'

Or from the command line:

$ python -m mscerts
/usr/local/lib/python3.7/site-packages/mscerts/cacert.pem

Addition/Removal of Certificates

This package is simply a mirror of the Microsoft store, and does not support any addition/removal or other modification of the CA trust store content. The sole provider of certificates in this store is Microsoft. See https://aka.ms/RootCert for more information.