TCP/IP Tutorial and Technical Overview - IBM Redbooks

complementary use of IPSec, an L2TP tunnel alone does not furnish adequate
security.
22.15 Secure Electronic Transaction (SET)
22.15.1 SET roles
SET is the outcome of an agreement by MasterCard International and Visa
International to cooperate on the creation of a single electronic credit card
system. Prior to SET, each organization had proposed its own protocol and each
had received support from a number of networking and computing companies.
Now, most of the major players are behind the SET specification (for example,
IBM, Microsoft, Netscape, and GTE).
The following sections describes at a high level the components and processes
that make up the specification. Refer to the MasterCard and Visa home pages for
more information about SET.
The SET specification defines several roles involved in the payment process:
The merchant This is any seller of goods, services, or information.
The acquirer This is the organization that provides the credit card
service and keeps the money flowing. The most widely
known acquirers are MasterCard and Visa.
The issuer This is the organization that issued the card to the
purchaser in the first place. Usually, this is a bank or
some other financial institution, which would know the
purchaser best.
The cardholder This is the Web surfer, who has been given a credit
card by the issuer and now wants to exercise his or her
purchasing power on the Web.
The acquirer payment gateway
This provides an interface between the merchant and
the bankcard network used by the acquirer and the
issuer. It is important to remember that the bankcard
network already exists. The acquirer payment gateway
provides a well-defined, secure interface to that
established network from the Internet. Acquirer
payment gateways will be operated on behalf of the
acquirers, but they might be provided by third-party
organizations, such as Internet service providers
(ISPs).
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