Payment Gateways are software and servers that transmit Transaction information to Acquiring Banks and responses from Issuing Banks (such as whether a transaction is approved or declined). Essentially, Payment Gateways facilitate communication within banks. Security is an integral component of all payment gateways, as sensitive data such as Credit Card Numbers need to be protected from any fraudulent parties. The card associations have created a set of rules and security standards which must be followed by anyone with access to card information including gateways. This set of rules and security standards is called the Payment Card Industry Data Security Standard (PCI-DSS or PCI).