| Summary: | 碩士 === 中華大學 === 資訊工程學系碩士班 === 99 === RFID(Radio Frequency IDentification) system is based on RFID tag and RFID reader. The reader can read and identify the data from tags by using radio frequency technology. Compared with traditional barcode, the reader can identify without contact to the tag, therefore it has been used in various system, such as supply chain management system, entrance control system, etc.
Because the RFID system use radio wave to transmit data, anyone can monitor the transmission of radio wave to get transmit content, or they can duplicate another tag by using the transmit data to cheat the entrance control system. Consequently, to protect the transmit data from duplicating or monitoring has become an important secure issue.
In this thesis, we proposed a time based data encoding algorithm to prevent transmit data from monitoring or duplicating. First, we create a specific encoding table which generated by expression, and we put the encoding table into the reader and the tag. When transmission initiate, we will use the MD5 to encode Unix time and query the encoding table by using encoded Unix Time, then send the result to the tag. The tag will verify the data to ensure it was sent by the trust reader, and send back the tag data by doing some expression if the reader can be trust. As time will only move forward, so we can ensure that Unix time is unique and won't repeat. In this way, the attacker can't monitor transmit data or duplicate the tag.
|
|---|
