As Radio Frequency IDentification (RFID) technology is widely used for micro-payment and item level tagging of supply chain management and asset management, RFID systems are suffered from many secure threats and attacks, especially for the RFID tags or related database containing private information which might be accessed illegally. Thus, the security and privacy issue of RFID requires much attention.
In 2007, Nohl in Virginia University proposed the physical analysis of Crypto-1 . Garcia and Jacobs researched the Mifare technology, which is an HF RFID technology and accomplished the clone attack on an ov-chipkaart card . Based on the study, Nocolas and Karsten attacked on the Oyster Cards in London public transportation system . In 2008, Anderson in MIT conducted exhaustive attack on subway card in Boston (Charlie Card), which draws the attention on the security issue on public transportation .RFID attack methods include spoofing, inserting, eavesdropping, replay attacking, counterfeiting, unauthorized access, tampering, denial of service, physical attacking, and tracing . To solve the security and privacy issues, many researches focus on the authenticating protocol. Recently, security protocols based on cryptographic algorithms attract more attention. One-way hash function, symmetric key algorithm, and public key algorithm are the 3 kinds of cryptographic algorithms used in RFID systems. For the low cost tag chip design, one-way hash function and symmetric key algorithm are used more frequently than the public key algorithm.
Literature  proposed the concept of “hash-lock” first. In the framework, only the value of hash is stored in a tag, and the key is stored in a background service. By temporary tag index meta-ID, the key can be attained. By sending the hash value of a key, users can lock the tag. In literature , the authors extend the hash-lock scheme with random index, and the “random-hash-lock” protocol improves the security significantly. RFID security protocols with hash algorithms are introduced in literatures  and .
Advance Encryption Standard (AES) algorithm is one of the most popular symmetric cryptographic algorithms. The overlapping authentication protocol with AES algorithms is first proposed in , to enhance the security of EPC system. In , a reader–tag authentication protocol based on AES is proposed to prevent cloning and replay attack. A gradual password transformation authenticating protocol further improve the safety of AES ().In UHF RFID systems, EPC Class1 Generation2 (C1G2) standard or ISO 18000-6C, the security issues are more serious with the burst of applications in retail, healthcare, anti-counterfeiting, where the data attached with RFID tags are sensitive. Thus it requires security-enhanced communication in the MAC level, and encryption engines in the tag chips.
In this work, a low-cost UHF RFID tag chip conforming to ISO 18000-6C with an AES cryptographic engine is designed and taped out. It can work on standard mode and security enhance mode. The digital baseband is verified in FPGA and the chip design is simulated with power consumption, speed, and area. The chip is taped out and measured in real scenario, and the result shows that the security scheme and chip in this paper work well.To the best of our knowledge, it is the first UHF passive RFID tag chip with AES algorithm in the baseband.
The rest of the paper is organized as follow: Section 2 reviews the related work; Section 3 introduces the AES cryptographic algorithm; Section 4 explains the hardware design of the AES engine and the digital baseband in this paper, Section 5 shows the simulation and testing results of the design, and Section 6 concludes the paper.