This function actually returns a CTL_CONTEXT pointer (please see CTL_CONTEXT on this site)

The CTL_CONTEXT must be freed by calling CertFreeCTLContext. CertDuplicateCTLContext can be called to make a duplicate. CertSetCTLContextProperty and CertGetCTLContextProperty can be called to store and read properties for the CTL.

            CTL_CONTEXT ctlContext = (CTL_CONTEXT)Marshal.PtrToStructure(ctlContextPtr, typeof(CTL_CONTEXT));

    public struct CTL_CONTEXT

    CTL_CONTEXT ctlContext = (CTL_CONTEXT)Marshal.PtrToStructure(

        ctlContextPtr, typeof(CTL_CONTEXT));