With the advent of the mobile payment era, QR code payment has become increasingly popular and very common. It can be seen in various scenarios such as shopping malls, supermarkets, hotels, and transportation.
The QR code payment model widely used in traditional stores has popularized the concept of mobile payment: customers display their payment codes on their phones, and merchants can complete the payment by scanning the code. This single offline QR code technology allows for verification and settlement with the backend through the merchant’s internet-connected cashier device when the mobile terminal is offline.
However, this simple settlement process is not quite applicable on buses. Due to the different usage environment, intelligent public transport card readers cannot guarantee the real-time and reliable verification and settlement of internet-connected transactions, especially in areas with poor network coverage, where single offline technology cannot meet the needs of mobile payments in bus travel scenes.
To compress the verification and settlement time of QR codes to within 300 milliseconds, current intelligent public transport card readers are widely adopting dual offline QR code payment technology.
In August 2016, Ant Financial collaborated with Hangzhou Public Transport to test the QR code payment model based on underlying dual offline technology on two pilot routes. After trying various payment technologies, Ant Financial believed that QR code technology is the most compatible and universal payment method, and best suited to user habits in the current technological environment.
Dual offline technology allows for identity verification and payment operations to be completed while both the user’s mobile terminal and the settlement terminal are offline, greatly reducing payment settlement time and enhancing the reliability of QR code payments. What seems like a simple dual offline QR code payment has overcome many obstacles on the path to commercialization.
QR codes have limited information-carrying capacity, and the more information they contain, the lower their recognition rate and decoding efficiency, which makes them prone to errors and longer recognition times. From a security perspective, additional verification information needs to be embedded in QR codes. This requires information encoding to be as compact as possible while maintaining algorithm security strength, striking a balance between information length and recognition effectiveness.
Furthermore, QR codes cannot engage in bidirectional information exchange. While intelligent bus card readers can recognize mobile phone QR codes, phones cannot obtain feedback information from scanning devices, leading to some delay in fare settlement. By introducing real-name authentication and Sesame Credit, users with good credit can enjoy “take the bus first, pay later” services.