If you have a passport, now is the time to renew it -- even if it's not set to expire anytime soon. In many countries, including the United States, passports will soon be equipped with RFID chips. And you don't want one of these chips in your passport. RFID stands for radio-frequency identification." Passports with RFID chips store an electronic copy of the passport information: your name, a digitized picture, etc. And in the future, the chip might store fingerprints or digital visas from various countries. By itself, this is no problem. But RFID chips don't have to be plugged in to a reader to operate. Like the chips used for automatic toll collection on roads or automatic fare collection on subways, these chips operate via proximity. The risk to you is the possibility of surreptitious access: Your passport information might be read without your knowledge or consent by a government trying to track your movements, a criminal trying to steal your identity or someone just curious about your citizenship. Security mechanisms are also vulnerable, and several security researchers have already discovered flaws. One found that he could identify individual chips via unique characteristics of the radio transmissions. Another successfully cloned a chip. The Colorado passport office is already issuing RFID passports, and the State Department expects all U.S. passport offices to be doing so by the end of the year. Many other countries are in the process of changing over. So get a passport before it's too late.