One of my security calculators used for Internet banking went t*ts up so I decided to tear it apart. Which proved far easier than expected.
These things are used here in .nl in combination with a chip-equipped smart card that we also use for electronic payments in shops (I think the Brits call this Chip-and-PIN or somesuch; its been around in .nl for ages)
Anyway, the fancy stuff is obviously underneath that black plastic glob, some kind of custom chip.