I made pinpam, a PAM module and utility to enable authentication on Linux with a brute-force resistant, TPM2-backed pin, intended to supplement (not replace) traditional password based Unix authentication. I created this because I wanted the convenience of a phone-like PIN unlock for my Linux device, with improved security over existing solutions like simply setting your password to a number. Generally a pin is less secure than a strong password, but they can be more convenient and easier for users to embrace. Please carefully consider your threat model when implementing any authentication service.