The following code is really simple. It restricts access to the current process. In this way no other process can open the process handle and for example terminate this process.
uses
  JwaWindows,
  JwsclSecureObjects,
  JwsclDescriptor,
  JwsclToken,
  JwsclTypes,
  JwsclAcl,
  JwsclKnownSid;
var
  SD : TJwSecurityDescriptor;
  hProcess : TJwProcessHandle;
begin
  JwInitWellKnownSIDs;
  hProcess := OpenProcess(READ_CONTROL or WRITE_DAC, false, GetCurrentProcessId());
  if hProcess <> 0 [...]

Sometimes it is necessary to change the security settings of a file or folder for getting or denying write access. With JWSCL this task is made very easy. However there are some pitfalls to avoid.
The following code will also be available in the example section of the source code. The application gets a file or [...]

This discussion continues How to use a SecurityAttribute structure.
Last time we used the SecurityAttribute parameter in CreateFile to change the security descriptor of the newly created file. However this approach did not add inherited access control elements from the parent folder. We are about to change that.
Filesystem and Registry-key inheritance is implemented since Windows 2000 [...]

I just found this complete example project. It shows how to get the integrity label of a file/folder in Windows Vista.
Get Vista integrity label source.