SHA-PASS

SHA-PASS lets you have a single master password for every service you use. It's free and totally ad-free, and requires no permissions.

Secure: Generated passwords are highly random. Your master password cannot be reverse engineered from any of the passwords generated by the app, so even if one of your services gets hacked, the rest of your passwords are safe. None of your passwords are stored on your device either, so you do not need to change them if it is lost or stolen.

Convenient: You can use the app on multiple devices without any synchronization--all you need to know is your master password and the name of the service you want a password for, and it will always generate the same password. The app remembers the names of the services you've generated passwords for, and your preferences for those passwords (mixed case, symbols, etc.) so you don't have to. It also checks your master password against a stored hash, alerting you if you mistype it.

How it works: As the name suggests, SHA-PASS computes the SHA-256 sum of your master password concatenated with the service name, represented as a hexadecimal string. It scans through this string until it finds a suitable mix of numbers and letters, and then converts letters to uppercase or symbols as necessary.