The code calculator functions largely in the same way as the
code card for authentication of secure transactions. The difference in the
modus operandi of the
code card and the code calculator is that the calculator never run out of one-time codes. The
code card has no protection from misuse once it falls into the wrong hands, while the code calulator typically asks for a
PIN code before you enter the
challenge number. The code calculator can also be reprogrammed if the code sequence is revealed (If a security breach happens at the central computer system or something). Reprogramming of the device is done at the bank, using standard
PCs and
IR to communicate with the device.
See the code card node for a practical example on how these devices are used.