Academic journal article Journal of Theoretical and Applied Electronic Commerce Research

Read / Write Performance for Low Memory Passive HF RFID Tag-Reader System

Academic journal article Journal of Theoretical and Applied Electronic Commerce Research

Read / Write Performance for Low Memory Passive HF RFID Tag-Reader System

Article excerpt


Certain applications of passive radio frequency identification (RFID), such as those in healthcare where the patient's name, identification or medical record must be stored, require data within a tag to be encrypted. Encrypted data within an RFID tag has the potential to affect the accuracy or time to read/write the data by the reader. The current research measures and analyzes the effects of encryption, distance of read and delay time between two read/write cycles on the accuracy of the read or write function in an RFID infrastructure. The research also measures and evaluates the time to read/write (R/W) data that is encrypted and compares this encrypted data with unencrypted data.

The data encryption standard (DES) encryption method is used in this research due to the limitation of the tag. A multi-functional interface has been developed for the user to test the performance using a High Frequency RFID reader. The measurements were repeated 1000 times for each R/W test.

The performance of R/W accuracy is not affected in any meaningful way by encryption even though there is an increase in memory requirement from 88 bytes to 128 bytes. The effect of R/W distance shows that the performance decreases with increase in the distance between the reader and the tag.

By inserting a small amount of delay time between different cycles, we can get a significant increase up to 100% accuracy for read function. However, the write accuracy is not affected as significantly as the read accuracy.

The effect of the encryption on the time to write the data on the tag shows that encrypted data group takes 70 ~ 120 milliseconds for the transmission more than the unencrypted data group.

We conclude that while the encryption does not have a significant impact on the accuracy of R/W, the distance and cycle delay does. Also, the encrypted data takes longer to write to the tag.

Key words: RFID, Healthcare, DES Encryption Method, Accuracy, Hashing Algorithm

1 Introduction

Currently, the unencrypted data transfer between the RFID reader and the tag is typical of most RFID transmission protocols. However, increasing security demands from industries such as healthcare or homeland security are starting to change this. RFID technology in various applications such as supply chain management, medical specimen tracking for healthcare, border security, library system, and smart shelf, etc., need security for authorized access , [1], [4], [7], [12] - [13], [15], [20], [23], [30], [41] - [42]. Without security protection of transmitted RFID data, inclusion of personal privacy information, confidential information and non-public information, in the transmitted data may not be allowed by the enterprise. Threats of RFID system are eavesdrops, relay attacks, unauthorized tag reads, cloning threats, location tracking, and denial of service from back-end server threats [14], [17], [28] - [29]. Encrypting data that require privacy is therefore essential.

In this research, various authentication and encryption methods for an RFID system have been discussed, presented and analyzed.

Two authentication methods are commonly used. The first method for authentication is to use a central database to authenticate readers and tags [8], [19], [21], [28]. The second method, which has been presented by Tan et al., introduces a new server-less authentication protocol which results in having a simpler infrastructure [34]. However, both methods need persistent connection to the database server or a persistently authenticated third party, limiting when and where it can be used.

While there are a significant number of encryption methods, the two most common and relevant ones have been compared in this research. One encryption method is a recently developed, lightweight method that is called "SASI" [5]. SASI uses only bit-wise operation, such as OR, AND, XOR, etc. to encrypt tag data. While this new approach was originally supposed to have the ability to disallow the tag to be tracked, other researchers have claimed that they have been able to track the tag [22]. …

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