Patent ID: 7565330

Claim:
A computer-readable medium whose contents cause a computing system of a transaction provider to: receive a request from a client computing device of a user to perform a transaction, the user having a security token that generates and outputs an alpha-numeric string that changes over time, the user's security token being different from the client computing device, the transaction provider being able to determine the alpha-numeric string currently being generated by the user's security token; and in response to receiving the request: identify the user requesting the transaction; identify the user's security token; determine an alpha-numeric string that should be currently generated by the user's security token; create a captcha image using the alpha-numeric string; create a transaction verification page comprising the captcha image of the alpha-numeric string as a visible watermark, the transaction verification page requesting a next alpha-numeric string to be generated by the user's security token to verify the transaction; and transmit the transaction verification page to the client computing device so that the client computing device can display the transaction verification page so the user can view the alpha-numeric string to determine whether the same alpha-numeric string is currently being generated by the user's security token and thus authenticating the computing system of the transaction provider.