This topic contains Programming Interface information.

ICSF provides callable services that perform cryptographic functions. For example, the ICSF encipher callable service enciphers data. You call and pass parameters to a callable service from an application program. See z/OS Cryptographic Services ICSF Application Programmer’s Guide for a description of the ICSF callable services.

Besides the callable services that ICSF provides, you can write your own callable services; these are known as installation-defined callable services.

To write an installation-defined callable service, you must first write the callable service and link-edit it into a load module. Then define the service in the installation options data set. Use the SERVICE installation option keyword to specify a number to identify the service and the load module that contains the service.

You must also write a service stub. To run an installation-defined callable service, you call a service stub from your application program. The service stub connects the application program with the installation-defined callable service. In the service stub, you specify the service number that identifies the callable service.

During ICSF startup, ICSF loads the load module that contains the service into the ICSF address space with the ICSF callable services. ICSF binds the service with the service number that you specified in the installation options data set.

This topic describes how to perform these tasks:

• Write a callable service.
• Define a callable service.
• Write a service stub.