A lot of the security moves we've seen lately from brokerages involve multi-layer authentication (e.g. Bank of America's SafePass from RSA) or "high tech" solutions like E*TRADE's RSA key fob. Interactive Brokers' Passcode Card is credit-card sized cardboard decoder that provides corresponding numbers to Index Numbers the website displays upon logging into the site. Essentially, there are two index numbers provided, and you look up each of those on the card and type in the corresponding 6-character alpha numeric code. The following image, which was included in the instruction package, shows how this works.

There are 224 codes on the card. I cannot remember my high school math classes well enough to know how to calculate the total number of permutations, but it's probably a lot, though not infinite. Nor is likely as many as an RSA-type keyfob. But good enough? Most likely.

The approach is interesting if a bit cumbersome from a user perspective. On the one hand, keeping a small card like this in your wallet is less of a hassle than a key fob, but it is still more of a hassle than recalling a picture on the login page to a website. It also might be a challenge for people with less-than-stellar eyesight since the printout is rather small. Moreover, it would be ideal if this were optional - like E*TRADE's key fob is.

Nonetheless, it is a good example of creativity in solving the ever present security challenge.