What is the difference between Z-Wave Security 2 (S2) and SmartStart?

Z-Wave Security 2 (S2) is a security and communication protocol that enhances the security, communication speed, and reliability of Z-Wave devices. To pair to a network, an S2 Z-Wave device shares its encrypted Device Specific Key (DSK) with the Z-Wave controller (i.e., security panel, hub, etc.) during Z-Wave enrollment. For more information about Z-Wave Security 2 (S2), see What is Z-Wave Security 2 (S2)?.

Z-Wave SmartStart is an enrollment process that builds on S2 to allow devices to be enrolled by simply scanning their QR codes instead of triggering devices during enrollment. All SmartStart devices use S2 security, but not all S2 devices are SmartStart-enabled. For more information about SmartStart, see What is Z-Wave SmartStart?.