In the Reference-based Payment Networks, Payments are linked to Requests via a paymentReference which is derived from the requestId and payment recipient address.
This paymentReference consists of the last 8 bytes of a salted hash of the requestId and payment recipient address, concatenated :
last8Bytes(hash(lowercase(requestId + salt + address)))
requestId is the id of the request
salt is a random number with at least 8 bytes of randomness. It must be unique to each request
address is the payment address for payments, the refund address for refunds
lowercase() transforms all characters to lowercase
