A radio frequency identification (RFID) tag encryption method and system using a broadcast encryption (BE) scheme are provided by encrypting an ID of an RFID tag, storing the encrypted ID in a server and the RFID tag, and storing information relating to a reader authorized to read out the RFID tag in the server so that the reader can read out the RFID tag by decrypting the encrypted ID based on the encrypted ID information read from the RFID tag and the reader information. When readers read out ID data from the RFID tag, a privileged reader can read the data. Thus, it is possible to block unintended information leakage to the readers. In addition, user usability can be enhanced since an attacker cannot perform an access lock on the RFID tag.