The NIST Special Publication 800-53 Revision 4 On-line Reference Database has been posted which contains the catalog of security controls from Appendix F and G of SP 800-53 Security and Privacy Controls for Federal Information Systems and Organizations (April 2013). This on-line database version provides customers with the functionality to quickly and efficiently browse the security controls, control enhancements, and supplemental guidance (including summarizing by control class, control family and control impact baseline) and search the security control catalog using user-specified keywords.