SNC Client Encryption is designed to enable secure communication between the client and SAP NetWeaver Application Server (AS) ABAP. It is not designed to provide a Single Sign-On (SSO) solution. There is currently no technical hinderance to prevent someone from entering the SNC name used to secure the communication between a client and server into the SNC name field of of User Maintenance (transaction SU01). This is, however, a violation of the license agreement.
For Single Sign-On (SSO) scenarios, we offer SAP NetWeaver Single Sign-On. SAP NetWeaver Single Sign-On centralizes and greatly simplifies the way users log on to systems and applications in your IT landscape. Seamlessly integrated into your existing authentication processes, it offers enhanced security through state-of-the-art technology. But that is not the only benefit SAP NetWeaver Single Sign-On has to offer. Reduce your operating costs by eliminating password-related helpdesk calls, and improve user productivity — more than enough reasons to start thinking about implementing a single sign-on solution in your company.
For more information, see http://help.sap.com/nwsso.
SAP Note 1684886 License conditions of SNC Client Encryption