【導讀】本文提供的是關(guān)于射頻識別技術(shù)的一項調(diào)查。最初開發(fā)的射頻識別標。簽用以取代條形碼。括使用的頻率范圍和標準。然而,隨著RFID電子標簽的普及,隱私問題就越來越受。該文概述了可能存在的個人私隱攻擊而且還介紹了應對措施。RFID標簽的用途是如此廣泛,所以在生產(chǎn)時降低成。本文綜述了此方案近期的研究進展狀況。列號或類似的標識符的要求。該標簽正在被大量使用于生產(chǎn)環(huán)境和超市的標簽項。應用，可能利用RFID技術(shù)如定位丟失物品,跟蹤移動的物體和其他人。RFID電子標簽預計增產(chǎn)到幾十億個。本文還介紹了RFID系統(tǒng)的可能擴展領域,同時也提出了。世界各地的軍隊仍在使用該技術(shù)的演變；第一個RFID商業(yè)應用是“電。RFID電子標簽成功邁進農(nóng)業(yè)如對動物的標簽。同時新成立的全球EPCglobalInc.繼續(xù)這項工作。該節(jié)描述的是RFID標簽由哪些部分組成、工作原理和確實存在的標簽類型，壽命長達5年的。

　　

【正文】 as descriptions for products and where and when a certain tag was scanned. In general a RFID system has a structure as depicted in figure 2. RFID readers scan tags, and then forward the information to the backend. The backend in general consists of a database and a well defined application interface. When the backend receives new information, it adds it to the database and if needed performs some putation on related fields. The application retrieves data from the backend. In many cases, the application is collocated with the reader itself. An example is the checkout point in a supermarket (Note that the given example uses barcodes instead of RFID tags since they are more mon。 however, the system would behave in exactly the same way if tags were used). When the reader scans the barcode, the application uses the derived identifier to look up the current price. In addition, the backend also provides discount information for qualifying products. The backend also decreases the number of available products of that kind and notifies the manager if the amount falls below a certain threshold. This section describes how RFID tags work in general, what types of tags exist and how they differ. The three frequency ranges that RFID tags typically use are LF, HF, and UHF. Also the difference between passive, semipassive, and active tags was explained and their advantages and disadvantages were pared. The section concluded by looking at different standards and showed the great interest of the industry by counting the number of issued and backlogged patents [US Patent Office]. 4. Security The expected proliferation of RFID tags into the billions has raised many privacy and security concerns. A mon concern is the loss of privacy when panies scan tags to acquire information about customers and then using data mining techniques to create individual profiles. This section describes possible scenarios where RFID tags can be exploited. Then it describes what mechanisms exist to defeat those threats or at least make them harder to execute. After that the section concentrates on attacks that are directed against RFID systems. As RFID technology bees more sophisticated and item level tagging promises more control and large savings in the supply chain management, panies are tagging items within their production process. To maximize the benefits panies start to require their suppliers to label all items delivered to the pany. For example, WalMart, Proctor amp。 Gamble, and the US Department of Defense require their suppliers to phase in itemlevel tagging. However, products are not the only entity tagged. Animal tagging is quite mon at large farms to keep track of their moving property. Also, tagging of humans 共 22 頁 第 15 頁 started to appear. In the Spanish Baja Beach Club, VIP members can get an implant that they can use to pay for their drinks in the club. The implanted tag is a Very Chip. AntiRFID activists created a few scenarios to show possible exploits if no precautions are taken. The most mon one the unauthorized scanning of tags in order to create user profiles. Other scenarios are scanning the medication a person is carrying to conjecture what illness the person might suffer, or a mugger scanning a crowd of people and singling out a person carrying many valuable items (even money, if tagged as proposed). If tags are replacing credit cards eavesdropping bees also a problem and must be addressed. The above mentioned issues are privacy concerns, but they are not the only issue. Authentication is also needed. For example, newer tags have rewritable memory available to store extra information during the production process. If stores rely on that information to determine the sales price for example, care must be taken so that customers do not change the type of the item to a cheaper one using portable readers. Also the kill mand, a mechanism to permanently disable a tag, must be protected from unauthorized access. Recently a paper raised some concerns in the RFID munity that claimed that cell phones can be reprogrammed to disable HF tags. In case that tags carry personal information (such as medical history, credit card numbers) a reader has to be authenticated and authorized before it is allowed access the data. In the previous examples the reader has to authenticate to the tag, there are also scenarios when the tag has to authenticate to the reader, for example to detect fed tags. Privacy This section describes methods to ensure privacy. This are usually mechanisms that kick in after the customer bought the product. They are either enabled at time of purchase or controlled by a userowned device. Kill mand: A mand supported by the EPC Class 1 and 2 tags. The mand will render the tag unusable once received. To prevent an adversary to call those mands they are password protected, EPC Class 1 tags have 8 bit passwords and EPC Class 2 tags have 32 bit passwords. A theoretical paper described how to reprogram a cell phone with a firmware update to make it scan for tags and once found to quickly enumerate over all possible passwords. Amore intelligent approach is described in [Oren06] where the password for the kill mand can be discovered by using power analysis on the back scattered signal. The power analysis works since the strength of the back scattered signal depends on how much power the chip on the tag drains which in turn depends on the amount and type of putation it does. Newer chips try to design the circuitry so that power analysis is not possible anymore. Sleep mand: A tag cannot always be killed. Killing a tag on a library book would require retagging the book upon return and therefore defeating the purpose. And yet the privacy of library uses should be protected. The sleep mand works similar to the kill mand. Once received the only mand accepted is