How to create code signing certificate in macOS

Code signing in macOS ensures the integrity and authenticity of apps distributed outside the Apple App Store. By signing your app with a certificate, users can trust that it hasn't been tampered with and that it genuinely originates from its developer.

The macOS operating system uses the Apple Developer Program for code signing of apps, ensuring they are malware-free and come from a known source. However, for internal distributions or personal projects, you can generate a self-signed certificate using the Keychain Access utility, which is built into macOS.

While a self-signed certificate won't offer the same level of trust as one from Apple, it's suitable for local development or limited distribution where the recipients trust the developer.

1. Launch Keychain Access.
2. Go to Keychain Access → Certificate Assistant → Create a Certificate from the menu bar.
3. Set the name of the certificate.
4. Click on Identity Type select list.
5. Select Leaf from the list.
6. Click on Certificate Type select list.
7. Select Code Signing from the list.
8. Click Create to continue.
9. Select CA or issuer from the list and click Create.

   Related: How to create Certificate Authority for Code Signing in macOS

10. Click Done to finish the process.