identifier string - A string used to uniquely identify a discount offer for a product. 
keyIdentifier string - A string that identifies the key used to generate the signature. 
nonce string - A universally unique ID (UUID) value that you define. 
signature string - A UTF-8 string representing the properties of a specific discount offer, cryptographically signed. 
timestamp number - The date and time of the signature's creation in milliseconds, formatted in Unix epoch time.