StripeEphemeralKeyPairGenerator
Generates an ephemeral keypair for Diffie-Hellman key exchange using the EC algorithm, as required for AReq message.
See "EMV® 3-D Secure SDK Technical Guide - 3.2 Diffie-Hellman process".
The implementation first attempts to create the KeyPair using Android's default security provider. This is based on guidance from Google to not specify an explicit provider.
https://android-developers.googleblog.com/2018/03/cryptography-changes-in-android-p.html