The rapid transit system of China’s most populous city is employing Nordic Semiconductor Bluetooth® LE wireless technology to help the 10 million people who use the network each day get to their trains and destinations faster. The point of sale (POS) ticketing system at the Shanghai Metro’s entry and exit gates uses Shanghai Dito Information Technology’s (Dito) ‘QR Code Bluetooth Security Signature Verification Module’ employing Nordic’s nRF52832 multiprotocol SoC. The SoC enables secure, offline signature verification to authorize customer payments in the event of a loss of network connectivity.

Smart subway access

To access Shanghai Metro, commuters can download the ‘Shanghai Daduhui’ app to their smartphone which is linked to their Alipay, China UnionPay, or WeChat account. From the app, users can generate a QR code that is scanned on approach to the entry or exit gates. Once verified, it opens the gates to allow the traveler access to the station platforms. In addition to Shanghai Metro, the POS ticketing system has also been rolled out across a number of other smart transportation facilities across China including Shanghai Maglev, Wuhan Metro, Dalian Metro, Xi’an Metro and Ningbo Metro. The system is used up to 150 million times each day, accounting for more than 35 percent of provincial transportation payment transactions in China, according to the company.

“Like Nordic, Dito is committed to the development of smart city technologies that help promote sustainability, and smart transportation systems are one component of that vision,” says Bruce Xie, CEO of Dito. “With Nordic’s in-depth cooperation and support, Dito’s offline QR Code Bluetooth Security Signature Verification Module is not only improving the convenience of citizen’s travel, but also greatly reducing the use of physical cards and tickets, and the resources required to make them.”

The most important thing we were looking for when developing the product was a SoC with highly stable and reliable Bluetooth LE protocol software, and in this regard, Nordic’s solution is a winner

Bruce Xie, CEO of Dito

Bluetooth verification module

Dito’s QR Code Bluetooth Security Signature Verification Module comprises a QR code module—which is linked to the main board of Shanghai Metro’s POS machine to provide QR code camera control—as well as the Nordic-powered Bluetooth verification module. The Bluetooth LE connectivity provides an alternative method of verifying the QR code and authorizing customer payments should the entry or exit gates suffer a loss of network signal. The nRF52832 SoC ensures secure Bluetooth LE connectivity between the entry and exit gates and the user’s smartphone. The SoC’s Advanced Encryption Standard (AES) offers strong protection, while its 64 MHz, 32-bit Arm® Cortex® M4 processor with floating point unit (FPU) and ample Flash and RAM can simultaneously manage the demands of AES and processor-intensive applications.

“The most important thing we were looking for when developing the product was a SoC with highly stable and reliable Bluetooth LE protocol software, and in this regard, Nordic’s solution is a winner,” says Xie. “The technical product information and reference designs are comprehensive, and the quick response from the excellent application engineers played an important role in ensuring Dito was able to successfully secure these major government smart transport projects.”

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