Toward an RFID Scheme for Secure Material Flow Tracing and Verification in Supply Chains

Introduction

RFID is an important wireless communication and pervasive computing technique, which is being massively used for automatic item identification and inventory management. As compared with traditional printed bar code, RFID offers several key advantages, including no light-of-sight readings and the recording of more information about the tagged items. With an increasing number of RFID applications in different fields, supply chain was the earliest driving force to use this technology and will continue to be one of the major application areas for RFID. The Department of Defense of the USA, major retailers such as Wal-Mart and Target, and important manufacturers such as Gillette and Procter & Gamble have mandated that all their supplied products be equipped with RFID tags (Li & Ding, 2007). Many supply chain organizations have invested considerably in the development and deployment of RFID infrastructure for better inventory management. Today, RFID has been seen as one of the most important technologies for supply chain management.

There are three major types of components in an RFID system – tags, readers and a backend database. A tag is physically attached to an item with a unique identification and shares a secret key with the backend database for authentication purposes. An RFID reader is a mobile device that recognizes the presence of a tag and initializes communication with it (Glover & Bhatt, 2007). The RFID backend database maintains an entry for each legitimate tag and often holds other information about the tagged item. Since the backend database and an RFID reader communicate through secure channels, in this paper our focus is on the authentication and communication between tags and readers.

In this research, we study secure material flow tracing and path verification in a supply chain using RFID communication and computing abilities. Material flow data provides important insights into the logistic patterns of items in a supply chain (Lee et al., 2008). We develop an RFID scheme, where an RFID tag attached to a package of products¹ is used to log the product flow information (in a very compact format) when the products move along a logistic chain. A supply chain server can then verify that the products have taken the correct path along a set of pre-designated supply chain partners to their destinations. Making the material flow auditable and evaluable is important to ensure product safety and compliance with organizational operation policies.

In our proposal, a supply chain consists of a set of participating partners (e.g., manufactures, wholesalers, and retailers) with their premises in different locations. A series of premises that the tagged items go through forms a material flow path. Products are traced and verified when they move in and out of each premise belonging to a supply chain partner. The goal of flow tracing is to ensure that the products follow the correct path that they are supposed to take. RFID tags and readers are deployed to ensure that only authorized supply chain partners can identify the tagged items in a secure and private way. Each scanning of a tag at a partner’s site leaves a mark on the tag’s memory, recording a logistic point which the tag has gone through along the material flow path.

From the functional perspective, our scheme provides not only an overall path tracing and verification through the entire supply chain, but also product identification within the scope of a supply chain partner. During their entire transportation process in the supply chain, tagged items often need to be processed in each intermediary partner’s premise for downloading, counting, packing, reorganizing, reloading, and possible transferring of ownership. Our protocol provides time-limited item control for each partner without the need to modify the tag’s existing operating scheme. Making the tagged items recognizable and traceable in and out of each partner without incurring additional costs for re-labeling provides significant efficiency and convenience in supply chain management.