Patent ID: 7992007

Claim:
A method of authenticating debit card transactions engaged in by a cardholder with a merchant on a communications network, said method comprising: a) establishing a connection over the network to a server of the merchant with a client being used by the cardholder to engage in a transaction on the network; b) providing over the connection to the client a web page containing a program operative to dynamically generate a keypad having a plurality of buttons that collectively define a geometry of the keypad, said plurality of buttons being dynamically generated and said keypad being employed by the cardholder to enter a personal identification number (PIN) via selection of the buttons with a pointing device of the client; c) obtaining over the connection the PIN entered by the cardholder; d) determining if the obtained PIN is correct for a debit card being used by the cardholder to engage in the transaction; e) repeating step a) through d) for each transaction the cardholder engages in on the network; and, f) with respect to two transactions engaged in by the cardholder, changing at least one of a size of at least one of the buttons and a spacing between at least two neighboring buttons by: i) randomly selecting the size of at least one of the buttons and/or randomly selecting the spacing between at least two neighboring buttons; ii) checking whether at least one of the size of at least one of the buttons and the spacing between at least two neighboring buttons changed between two transactions; and, iii) repeating steps i) through ii) until at least one of the size of at least one of the buttons and the spacing between at least two neighboring buttons changed between the two transactions.