snc/r3int_rfc_secure is a SAP Parameter attribute which is used to control Use SNC for internal RFC-Communications information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
This parameter controls whether RFCs that go to the same SAP system via
internal destinations are secured with SNC. Due to possible performance
problems you should declare whether this is necessary because the same
level of security can be achieved by other measures too. See also the
discussion of this parameter in the security guide for system
administrators.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.