可抵擋非同步化及暴露攻擊的極輕量雙向身份認證協定

Abstract

無線射頻識別是一個無線通訊技術，透過無線電訊號，自動辨識與追蹤物品。 現今無線射頻識別應用廣泛，安全及個人隱私問題受到大量的關注。因為極輕量標籤的電力、運算與儲存空間非常有限，只能執行簡單的位元運算，所以容易遭受許多攻擊，像是阻斷服務、追蹤、非同步化和暴露攻擊，而其中非同步化和暴露攻擊對於極輕量雙向認證協定影響甚鉅。非同步化攻擊使得讀寫器與標籤儲存的共享秘鑰不同步，造成讀寫器再也無法與標籤相互認證，暴露攻擊則讓攻擊者能取得標籤的身份，使得攻擊者可以偽裝成合法的標籤與讀寫器進行認證。現有的極輕量雙向認證協定對於非同步化及暴露攻擊無法有效的防範，所以本論文提出一個可抵擋非同步化及暴露攻擊的雙向身份認證協定，在雙向認證的階段，以隨機數作為排列函數的其中一項輸入，使得攻擊者無法從讀寫器與標籤認證的訊息中，推得標籤的身份，以保護使用者的隱私，降低暴露攻擊的成功率。在索引假名及秘鑰更新的階段，我們提出隨機更新共享秘鑰的方法，降低非同步攻擊的成功機率。我們也針對非同步化及暴露攻擊對現有和我們的極輕量雙向認證協定做了詳盡的分析與比較。分析結果顯示，相較於現有的協定，我們的方法能有效地抵擋前述攻擊。我們的方法將暴露攻擊之位元(Bits)攻擊的成功機率降至0.98%，並讓非同步攻擊之交握(handshaking)攻擊的成功機率從100%降低為25%。

Radio frequency identification (RFID) is an automatic identification technology to store and retrieve data wirelessly. Nowadays, RFID is one of the main technologies used to build ubiquitous systems. Security and privacy problems of a RFID system attract a great quality of attentions since ultra-lightweight tags have very limited capabilities, in which protocols can only use bitwise operations. The existing protocols can not resist many attacks such as DoS, traceability, de-synchronization and disclosure attacks. De-synchronization and disclosure attacks are two important threats among these attacks. Therefore, we propose a new ultra-lightweight authentication protocol resisting de-synchronization and disclosure attacks. The proposed protocol is inspired by the RAPP protocol. We use a random number as an index of permutation operation in the mutual authentication phase to defend disclosure attacks.In the IDS/Keys update phase, we design a random approach to randomly update the shared secrets between a reader and a tag to reduce the success probability of de-synchronization attacks. We discuss security analysis and show how de-synchronization and disclosure attacks work on our and the existing ultra-lightweight authentication protocols. The results show that our protocol can decrease the success probability of disclosure (bits) attacks to 0.98% and reduce the success probability of de-synchronization (handshaking) attacks from 100% to 25%.