PHP Manual Function Reference Credit Card Processing SPPLUS SPPLUS Functions Predefined Constants calcul_hmac SPPLUS Functions Table of Contentscalcul_hmac — Obtain a hmac key (needs 8 arguments)calculhmac — Obtain a hmac key (needs 2 arguments)nthmac — Obtain a nthmac key (needs 2 arguments)signeurlpaiement — Obtain the payment url (needs 2 arguments)