- Remove status_code and status_message from individual Payment Protocol messages
- Remove EncryptedInvoiceRequest, EncryptedPaymentRequest, EncryptedPayment and EncryptedPaymentACK messages from protobuf definition file
- Add ProtocolMessageType enum and ProtocolMessageType and EncryptedProtocolMesssage messages to bip-0075/paymentrequest.proto definition file
- Update BIP75 text to remove old individual message encryption paths and include new encapsulating messages for self-contained PaymentProtocol communication (including errors) over various transport layers
- Add initial list of status codes
- Update BIP75 to use AES-256-GCM and remove message hash as GCM mode provides authenticated encryption
- Update ECDH calculation to use SHA256 hash of ECDH's X point instead of the raw X point itself
- Add Updated Messages section to describe the status_code and status_message
- Separated Message and Communication Errors into Payment Protocol Errors and Communication Errors
- Add first draft Payment Protocol error codes
- Update InvoiceRequest Message Creation description amount example to return Payment Protocol error in the case of an issue with the amount.
