When Alipay makes barcode payment, the payment code is equivalent to the authorization code, which is used for payment. This method is the most widely used offline at present, and it is also a payment method vigorously promoted by Alipay.

Alipay payment process: users open Alipay APP and select payment. At this time, the APP will generate 18 payment authorization code to Alipay server. The merchant will scan the user's payment code with a scanning gun and analyze it to generate 18 as the digital payment code. The merchant system initiates a payment transaction, and submits the just analyzed information such as payment code, transaction amount and merchant ID to the payment background. After Alipay server judges the validity of the order, it will deduct the money.