# SAM-PAY: A Location-Based Authentication Method for Mobile Environments +
## 6 Test-Bed Description  
This section provides details of the test-bed put in place in the frame of a concluded research project to demonstrate the functionality of the proposed refueling service exploiting the SAM-PAY method. The test-bed was aimed at validating the main phases expressed in the proposed service and evaluating the time required to complete the SAM-PAY-enabled transaction (about 10 s). The test-bed was installed in a controlled environment inside a research institute, and a test LE was situated at a Telecom provider in Italy. The test-bed was not, however, thought to be available to large-scale users until additional tests (e.g., against potential malicious users) were performed. However, we note that some components (e.g., the POS and the SP) can be easily adapted in other use-case scenarios, like hospitals, universities, or public administration offices. Figure 1 shows the test-bed, where the four screenshots depict the core components of the system described in Section 5.2. On the right-hand side of the picture, a fuel dispenser is clearly visible. A dispenser from a leading Italian company supplying electronic and computer science technology services for automated oil distribution has been used. This dispenser can deliver up to 2 products and is configured to manage two nozzles. The unit, containing the electronics, which is separated from the hydraulic part, allows the installation of different remote-control stations for pre- or post-payment solutions. In the test-bed, we integrated the fuel dispenser with the Maser Automation MAC Secure Plus remote-control station (i.e., the white tower shown in the middle of Figure 6), which is an Outdoor Payment Terminal (OPT) in line with the level of security requested for electronic payment transactions via smart-card. It implements an independent payment module that has obtained PCI (Payment Card Industry), PED (PIN Entry Device), EMV Level 1, and EMV Level 2 certifications. In particular, the payments can be performed both with credit cards (magnetic stripe and microchip) and debit cards through the panel POS (screenshot 1) developed by a multi-national company whose business is focused on technology, telecommunications, security, and home automation. We customized this POS by integrating a Zigbee concentrator as a COM peripheral able to manage all the short-range connections coming from UTs (screenshot 2). In practice, we used a Texas Instruments CC2430 2.4 GHz IEEE 802.15.4/ Zigbee chipset, the same one that we integrated in the UT prototype.  
As far as the UT prototype is concerned (screenshot 3), it was designed and developed to host both A-GPS and Galileo-ready chipsets like SIRF Star III or ublox 5. It also integrates a communication unit for the management of short-range and wide-area professional and commercial communications technologies: GPRS/USSD/SMS, Wi-Fi, Bluetooth, Zigbee, VHF, TETRA, and DMR. The platform has some additional peripherals like a 3-axis accelerometer for the identification of crashes and falls, a USB connector for fast data transfer, and some RAM banks (2 Mbytes) for data storage. Finally, the UT integrates an HMI to allow user interaction during payment procedures. We used a Windows CE-based development platform (screenshot 4) accessible through a serial port connection. For cryptographic operations, the OpenSSL library [71] was employed in an application developed in C language for the logical implementation of the modified LDEA algorithm. All the above components have been integrated with the SP and the LE according to the architecture and workflow described in Section 5.2.