Connecting to PaymentTrust's Secure Transaction Network - WorldPay

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Authentication
Communication
STlink within STN
Security
Network TCP/IP (Internet)
Access
SSL / VPN
(Cryptography)
* Platform Independent
Fig. 3 Secure Transaction Services Network - Communication Protocol Layers
NETWORK LAYER: This layer is handled exclusively by the designated Internet Service
Provider.
SECURITY LAYER:
a) The Security Layer will be handled either by 128-bit SSL certificate or a secure
tunnel Triple DES VPN conforming to the IPSEC standard. PaymentTrust Ltd. will
provide at an additional cost the VPN hardware equipment if required.
b) The Security Layer also includes the Merchant access layer into the Secure
Transaction Network (STN). This involves the use of a Merchant ID, a Username
and Password, which are sent as a string to STLink.
STLINK APPLICATION:
The Application Layer manipulates data using HTTP(S) GET/POST request or an XML
request and communicates via standard ports 443 for SSL or port 80 for VPN. The system
can intelligently process a request whether GET/POST or XML. The request (an input string)
is routed with the STN to the appropriate service for processing – PT, RG, and others. The
system returns the response to the requesting URL. Should the delivery fail, the system will
capture the error, inform the merchant and store the information for later reporting. Captured
errors are further analyzed. When the delivery is successful, the merchant receives a
response and stamps each transaction with an appropriate message code. Please note that
for larger strings sizes the GET method should not be used.
The input string/message sent by the Merchant is stored in a serialized database with a
unique serial number. PaymentTrust Ltd. maintains a log of any transaction requested by the
Merchant and responds with a real-time message which will encapsulate information
regarding:
Integrity of the message sent by the Merchant – if a message is received truncated/
incomplete or in a tampered condition, the STLink application will capture the error and
will respond with the appropriate error message to the merchant’s system;