Significant progress toward development of an industry consensus on standards for secure building automation and control systems has been made byASHRAE's BACnet committee. The committee's Network Security Working Group reached agreement on a proposal to use a shared-key technology to create "secure networks" within BACnet. The agreement was made at ASHRAE's 2003 Annual Meeting June 28-July 2. Guidance on creating secure networks would be included in ANSI/ASHRAE Standard 135-2001, BACnet -- A Data Communication Protocol for Building Automation and Control Networks, through future addenda.