HostProtectionAttribute.SecurityInfrastructure Property

// Use the enumeration flags to indicate that this method exposes shared  
// state, self-affecting threading, and the security infrastructure.
[HostProtectionAttribute(SharedState=true, SelfAffectingThreading=true,
     SecurityInfrastructure=true)]
// ApplyIdentity sets the current identity. 
private static int ApplyIdentity()
{
    string[] roles = {"User"};
    try
    {
        AppDomain mAD = AppDomain.CurrentDomain;
        GenericPrincipal mGenPr = 
            new GenericPrincipal(WindowsIdentity.GetCurrent(), roles);
        mAD.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);
        mAD.SetThreadPrincipal(mGenPr);
        return Success;
    }
    catch (Exception e)
    {
        Exit(e.ToString(), 5);
    }
    return 0;
}