I need some help with implementing a secure connection to validate merchant for Apple Pay for Web.
I prefer to implement it with Java HttpClient, but also other solutions are possible (e.g. I found https://github.com/norfolkmustard/ApplePayJS/blob/master/apple_pay_comm.php in PHP, but still don't know how to obtain all the keys).
What I already have got:
1. apple_pay.cer - from Apple
2. merchant_id.cer - from Apple
3. server with SSL (TLS1.2, and required ciphers)
4. I have validated domain in Apple
I'm not sure what to do with the obtained keys - should I convert them to PEM format, should I add one of them to trust store? In the PHP example above there is also private key - what kind of key it's: my private key? one of the keys generated by Apple has it and I need to extract?
Is there any guide what to with keys after obtaining them, and how to encode transmission with them (the programming language doesn't matter, I just want to see steps)?
br,
Adrian