One-Time Passwords are available as a means of further securing your Square Enix account.
A "One-Time Password" is a six-digit number shown on a screen using either a key-ring like the Square Enix Security Token or a smartphone application, such as the Square Enix Software Token.
A security token is a device for displaying One-Time Passwords that will dramatically improve account security. Pressing the button will display a One-Time Password on the device's LCD screen which will provide you the required one-time password needed to access your account.
Square Enix Security Tokens may be purchased from the Square Enix Store for $14.99.
The Software Token is a free smartphone application designed to display One-Time Passwords that will dramatically improve account security. After registering for the service, a One-Time Password will be shown on screen every time the application is launched.
The application can only be used on Square Enix accounts by customers who have purchased either FINAL FANTASY XI or FINAL FANTASY XIV and registered the corresponding registration codes.
Software authenticators (Google Authenticator, Microsoft Authenticator, etc.) are free apps developed for smartphones (iPhone or Android) for the purpose of displaying one-time passwords.