The pressure to get RFID tags down to five cents each has led to eliminating security features, making them easier to crack, according to a well-known cryptographer.

Adi Shamir, a computer science professor at the Weizmann Institute, said at last week's RSA Conference that he used an antenna and digital oscilloscope to monitor power use by RFID tags. The patterns reveal when a tag received a correct or incorrect password. He tested only one brand of chip, but found it "totally unprotected."