| 摘要: | 近年來，短距無線通訊(short-range wireless communication)技術吸引許多關注並具有許多應用。藍芽、802.11(Wi-Fi)、ZigBee、超寬頻(Ultra WideBand)、近場通訊(Near Field Communication, NFC)等標準，都是使用短距無線通訊技術的典型範例。基於如傳輸速度、傳輸距離、耗電量等的不同特殊要求，這些標準都有其立足的特點；其中NFC是最近最熱門最受到注目的技術之一，經常被整合到智慧型手機中。NFC自無線射頻辨識(Radio Frequency Identification, RFID)技術演變而來，由 Philips、NOKIA和Sony主推，在13.56MHz頻率運行於20公分傳輸距離內。NFC設備具有卡片模擬模式(card emulation mode)，在這個模式下NFC設備就相當於一張採用RFID技術的IC卡。NFC設備另外具有讀卡器模式(reader/writer mode)可以讀取NFC標籤中資料或將資料寫入NFC標籤中，也具有點對點模式(P2P mode)，可以與另一個NFC設備直接交換資料。
在本論文中，我們提出一個使用NFC技術將留言板電子化的系統，並且達到使用者的隱私性(privacy)、不可否認(non-repudiation)及完整性(integrity)。在此系統中，使用者的NFC設備必須先向系統中的伺服器進行註冊，取得一對公鑰與私鑰以及公鑰證書。我們採用非對稱式加密機制進行留言加密與數位簽章的嵌入，最後NFC設備使用讀卡器模式將留言寫入NFC標籤。如此可以達到留言板電子化的目的，並且確保只有NFC標籤的持有者才可將留言正確解密(即隱私性)，而且留言者不可否認已發送出留言(即不可否認性)，及留言不會被竄改(即完整性)。我們並於Android平台實作NFC留言系統以驗證系統的實用性。
;Recently, short-range wireless communications technologies have attracted much attention and been applied to many applications. Bluetooth, 802.11 (Wi-Fi), ZigBee, UWB (Ultra WideBand), and Near Field Communication (NFC) are exemplary standards using such technologies. Based on the special requirements of transmission speed, transmission distance, and power consumption, every standard has its own niche; NFC is the most popular among the standards and is usually integrated into newly-launched smart phones. NFC, developed by Philips, NOKIA and Sony, is based on RFID (radio frequency identification) and operates at 13.56 MHz frequency with a transmission distance of 20 cm. NFC devices support three modes of operation: card emulation, reader/writer and peer-to-peer. The card emulation mode enables NFC devices to act as RFID smart cards. The reader/writer mode enables NFC devices to read or write information to NFC tags. The peer-to-peer mode enables two NFC devices to communicate with each other to exchange information and share files.
In this thesis, we propose to design an electronic guestbook system using the NFC technology with the privacy, non-repudiation and integrity properties. In this system, all of the NFC device must be registered with the system server, and then get one pair of a public key and a private key, as well as a public key certificate. We use the asymmetric encryption mechanism to encrypt messages and to produce digital signatures; we then make NFC devices write the encrypted messages and signatures into NFC tags by using the reader/writer mode. In this way, we can achieve an electronic NFC guestbook system ensuring that only the holder of an NFC tag can decrypt messages properly (i.e., the privacy), the sender of messages cannot deny having sent the messages (i.e., the non-repudiation), and messages cannot be tampered (i.e., the integrity). We have implemented the NFC guestbook system on the Android platform to show the system practicability. |
