What is the approach to implement bank card payment in android mobile app?

Question

Android

It is necessary to build in the mobile application the ability to pay for material goods or services using a bank card associated with the user's account in the program (not Google). The application works in client-server mode. The following is not clear:
1. Where to store and in what form (encryption) the user's payment card data - on a mobile device or on a backend.
2. What are the principles for ensuring the security of stored card data if they are located on the server and on the client. Those. what algorithms to encrypt, etc.
3. How to securely transfer payment card data between the client and the backend?
4. Which party makes the payment (interacts with the payment system) - a mobile device or a backend?
5. What are the ready-made services for making such payments in Russia?
6. Should I use the option to pay through the Google Play platform (As far as I know there is a high transaction fee of 30%)?
Maybe there are ready-made best practices, how to do such things in principle?

Answer 1

If there are few goods, then the best choice is a standard Google payment.
And to get a card tied to an account - I think it’s generally unrealistic, otherwise it’s a security hole.

Answer 2

Wait until Google I/O ends. They promised to show Android Pay.

Answer 3

PayPal?
There is also stripe, but you need a company in the USA or in one of the countries: https://stripe.com/global
You can receive money from anywhere

Answer 4

You can use the OpenIAB lib. Through it you can pay in several stores.