Over 20 million PCs worldwide are equipped with a security chip called the Trusted Platform Module, although it is as yet rarely activated. But once merchants and other online services begin to use it, the TPM will do something never before seen on the Internet: provide virtually fool-proof verification that you are who you say you are.

Some critics say that the chip will change the free-wheeling Web into a police state, while others argue that it’s needed to create a safe public space. But the train has already left the station: by the end of this decade, a TPM will almost certainly be part of your desktop, laptop and even cell phone.