基於Hamming Distance之上的RFID相互認證協定

Abstract

RFID的全名是無線射頻技術，是種透過無線射頻的方式來傳送辨識資訊的一種技術，其應用的層面相當廣泛，在現今社會中的能見度也越來越高，像是電子錢包、門禁卡、…等應用之上，都可見到RFID技術。而因為RFID的標準在被動式標籤的硬體資源受限情況下，隱藏著許多的安全性問題，像是標籤追蹤、重送攻擊、阻斷式攻擊、仿冒攻擊、向前安全或中繼攻擊等。針對此類安全問題，有許多方式的研究持續被提出，使用CRC函式亦為其中一種方式。

在RFID標準中有提供CRC函式來作錯誤偵測，且該函式可以將不定長度的字串擴展或縮減為固定長度。因此，可利用此方式來對不定長度的字串去做比較，然後藉此比較所得到的差異來判斷攻擊者是否存在於RFID系統中。

本篇論文提出的MAPHD協定是使用漢明距離的計算作為其字串的比較方式，因為其計算的電路並不複雜，且效能也相當優良。經討論與比較後得知，在安全問題上有著相當好的防護能力且對於標籤的計算負擔是不重的。

RFID is a technology that uses the RF technology to transfer ID. The RFID applications include electronic wallet, access control card, … , etc. Because the passive RFID Tag has resourse constraint issues, the RFID systems usually have some security problems, such as tracing attack, denial of service, forward security, replay attack, impersonation attack and relay attack, etc. To address the security issues, lots of solutions had been proposed.

The RFID standard supports CRC function, and the function can extend or shrink a variable length string to a fixed length string. So, we can use it to compare the different of variable length strings. And we can then use the result to detect the security attack in the RFID system.

The circuit of hamming distance isn’t complex, and it has high performance. In this thesis, we proposed an authentication protocol, MAPHD, which uses the hamming distance to compare the key strings. With carefull discussion and comparison, we conclude that our protocol can provide good protection for the security of RFID applications with lightweight overhead of tag computation.