Where to read about bridge applications to the site interface?

Question

Mobile development

Good people.
The topic is not new. But sharp, I think. The issue is the development of a cross-platform application, the communication center of which, of course, will be a web server. In short, this is a system in which the buyer can leave the order, and the seller can accept / reject.
The complexity of the issue lies in ensuring the safety of the process. After all, the entire history of the buyer's financial relations should be available from the application, and for this you need to connect to the server and request personal information on the account.
Details are redundant. It is important to choose the principle by which the data exchange protocol will be conducted.
What is the safest and most effective method you recommend? Or where to read up-to-date information on this issue?

Answer 1

To begin with, if the purpose of the question is to choose a protocol, then the choice of iOS and Android hubs seems strange: for both platforms, there are a lot of implementations of very different protocols, with different conditions of use. Otherwise, speaking about the protocol, it is not clear what the platforms and cross-platform have to do with it.
You can start reading here: Transport Layer Security . The possibilities of TLS / SSL are well described there, but in short, I think this protocol will suit you. Both in terms of the level of security and the huge number of use cases .