A struct that a recipient uses to generate a payment code and process notifications. This is
invariant with regard to sender and needs to be constructed only once (unique per BIP32 seed).
Represents a connection between a sender and a recipient from the recipient side. A recipient uses
this to generate addresses and their associated private keys for a particular sender.
A struct that a sender of funds uses in combination with a recipient’s PaymentCode in order
to send notifications and calculate payment addresses. This is invariant with regard to
recipient and needs to be constructed only once per account (unique per BIP32 seed + account).
Represents a post-notification relationship between a sender and a recipient from the sender
side. A sender uses this to interact with a payment code after creating a notification.