The Square Enix Security Token was made available to players starting in April 2009 as a safeguard against the hacking of players' Final Fantasy XI accounts. The security tokens, managed through Square Enix Accounts, will also be usable for Final Fantasy XIV.
As of summer 2009, security tokens were still being sold for $9.99 each through the PlayOnline Viewer. Defective tokens can be returned for a period of three months.
Using a Square Enix Account, players connect the serial number of their security tokens with their specific PlayOnline ID numbers. Each token generates a temporary password every 30 seconds in correlation with a matching password generated at Square Enix. The passwords expire soon after they are used. Hacking into the security tokens is impossible because they are not connected to the computer. Brute-forcing passwords is also nearly impossible because the current passwords constantly change regardless of whether the button on the security token is pressed.
Players of Final Fantasy XI have been given Mog Satchels in exchange for buying security tokens. The mog satchels give players an additional method of storage that matches the sizes of their gobbiebags. More useful is that mog satchels can be accessed from anywhere in Vana'diel. Players must link their PlayOnline ID to a security token before they can access their gobbiebags.