Certificate Authority or CA allows you to sign digital certificates. In macOS, you can create your own Code Signing certificate and then configure your own CA to sign the certificate.
Creating your own CA is useful if you are running a development environment or signing modules or programs using codesign tool on your system. Certificate Authority can be created in macOS using the Keychain Access utility.
Steps to create Certificate Authority for Code Signing using Keychain Access:
Launch
Keychain Access.

Go to
Keychain Access →
Certificate Assistant →
Create a Certificate Authority from the menu bar.

Set a name for your
CA.

Click on
User Certificate select list.

Select
Code Signing from the list.

Check on
Let me override defaults checkbox.

Enter the email address for your
CA.

Click on
Continue.

Accept defaults for
Certificate Information and click
Continue.

Click Continue if you encounter this warning.
Enter certificate information and click
Continue.

Accept defaults for
Key Pair Information For This CA and click
Continue.

Accept defaults for
Key Pair Information For Users of This CA and click
Continue.

Accept defaults for
Key Usage Extensions For This CA and click
Continue.

Accept defaults for
Key Usage Extensions For Users of This CA and click
Continue.

Click on
Include Extended Key Usage Extension.

Click to check the
Code Signing checkbox.

Click
Continue.

Accept defaults for
Extended Key Usage Extensions For Users of This CA and click
Continue.

Accept defaults for
Basic Constraints Extension For This CA and click
Continue.

Accept defaults for
Basic Constraints Extension For Users of This CA and click
Continue.

Accept defaults for
Subject Alternative Name For This CA and click
Continue.

Accept defaults for
Subject Alternative Name for Users of This CA and click
Continue.

Click
Create to create the
CA.

Close the
Certificate Assistant window and open
Keychain Access.

Double click on your newly created
CA in
login →
My Certificates.

Click on
Trust.

Click on
When using this certificate select list.

Click on
Always trust.

Close the
CA information window.

Authenticate to the system to enable your changes.

Discuss the article:
Comment anonymously. Login not required.