receiving at a host computer system including a processor, from each of a plurality of payment processing organizations, a set of {TAIL ~ security requirements} defining {HEAD ~ protocols} for implementing commercial transactions over the shared network using instruments identified with the payment processing organization 
receiving at a host computer system including a processor , from each of a plurality of payment processing organizations , a set of { TAIL ~ security requirements } defining { HEAD ~ protocols } for implementing commercial transactions over the shared network using instruments identified with the payment processing organization
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH