"A transparent token the size of a postage stamp and costing just a penny to make can be used to generate an immensely powerful cryptographic key." Marie asked for my comments on this. The fact that the token cannot be copied doesn't mean the ones and zeros read from it cannot be copied, so this actually doesn't make a very good "cryptographic key." All you need to open cryptography is the ones and zeros. Not a card. Furthermore, the articles talk about reading the key from multiple angles, but cryptographic systems only have one password, so this is a capability mismatch again. In an environment like an ATM machine where you are fairly certain that you are actually reading from a physical card this might be a more secure (albeit expensive) replacement for a magnetic strip. It may also find its way into door locks. However, you won't find such a reader in your computer nor for scanning credit cards, as in such environments there is no way to be sure that the "key" is actually coming from such a card and not from something else. So in sum, the technology is interesting, but its not all that useful. My comments on the optical keys | 
