Language support: C# (.NET)

[chriskilding]

Tracking support for native TLS certificate verification in C# and the .NET stack.

Because .NET is cross-platform, we need to consider not only whether it can access the Windows Certificate Store, but also native trust stores on other operating systems.

Runtimes to consider:

• CLR / CoreCLR / whatever is in .NET 5+
• Mono

[chriskilding]

Windows

If you are

• using the official CLR
• for Windows
• using the System.Net APIs (for example, System.Net.Http.HttpClient and System.Net.Security.SslStream)

it will use the native Windows Certificate Store to do TLS cert verification

(Hat tip to https://stackoverflow.com/q/63798167 where you can see that the user has added their custom certificate to the Certificate Store, in order for their C# program to see it.)

macOS

When using the System.Net APIs, on the official CLR, on macOS, it will use the Keychain to do TLS cert verification.

This is supported on all recent versions of the CLR. (This work was done in dotnet/corefx#17011 for dotnet corefx v2.0.0.)