What type of middleware is used for the Square credit card reader and its website

I am trying to understand how the https://squareu开发者_StackOverflow中文版p.com/ square Credit Card reader works.

What would be the underlying middleware that is being used to

1. send the data to the squareup server,
2. process the payment
3. send verification to a user of a successfull payment

This is implmented on the iPhone, could there be a generic middleware that could be used for other devices to access this service created, so we could have all type of smartphones access a similar service language independent?

Also what security protocols would be used to ensure the data is sent encrypted over the network?

Their own website contains details about their security technology. They appear to use common and trusted technologies like SSL, which isn't a surprise.

If you want to build an application that integrates with their service, you should contact them. It's possible that they will require you to purchase a license in order to do so. They would also be the authority on the protocols and middleware required to integrate with it.