SETREF and SET

SETREF implements only the SET protocol. It provides little support to the application layer for higher-level application requirements.

For example, SETREF is not concerned with general-purpose payment mechanisms, nor does it provide code for "back end" support, such as code to interface to the existing financial network. For payment applications, the application layer is concerned with processing payment information. For registration applications, the application layer is concerned with processing certificate requests. Examples of application-layer operations that SETREF does not perform include:

Computing a batch total
Opening a socket connection
Managing a local cache or log

Instead, SETREF implements the core functionality common to all entities defined by SET: the cardholder, the merchant, the payment gateway, and the certificattion authority. Examples of operations that SETREF does perform include:

Encrypting data
Checking cryptographic hashes
Marshalling parameters

Although SETREF includes several demonstration applications, they are not fully formed SET applications. Rather, they are intended to demonstrate the use of SETREF for building SET applications.

Some fields that may appear to belong in the application layer, such as the purchase request date (pReqDate), are initially set by the application layer, but they are then managed by the protocol layer. The API Reference documents the messages that reference such fields.