The password generator uses the secure bcrypt algorithm to create strong passwords that are also unique for every site. You just have to remember a single passphrase and the tool will create different passwords for all your online accounts with a click.
Some sites requires you to change passwords every month. In that case, just append the month name to the passphrase and have unique passwords every month.
You can download the password generator code from Github and run on a USB key. Or upload the folder to Dropbox and access the tool from all your other computers.
The passwords are generated inside your web browser itself. None of your data is shared, uploaded or stored anywhere and you can even use the tool in offline mode.