A system entity that requests and subsequently enforces authorization decisions.
						                            Source(s):
						                            
								                            
                                                                    CNSSI 4009-2015
										                            
                                                                            NISTIR 7657									                            
						                            
						                            
						                        
					                            
						                              Mechanism (e.g., access control mechanism of a file system or Web server) that actually protects (in terms of controlling access to) the resources exposed by Web services.
						                            Source(s):
						                            
								                            
                                                                    NIST SP 800-95
										                             under Policy Enforcement Point (PEP) 
                                                                            OASIS: A Brief Introduction to XACML