A Secure and Efficient Access Control Scheme for Shared IoT Devices over Blockchain

Table 1

Symbol description.

Symbols	Description
CA	Certificate authority
	The user
	The gateway
	The shared device
	Negotiated session key
	The service item
	The symmetric encryption algorithm with the session key
	The certificate of user, gateway, and device
	The blockchain address of user, gateway, and device
	The secret key of user, gateway, and device
	The public key of user, gateway, and device
	Elliptic curve signature algorithm with the secret key of CA