DAKEs: Decentralized Authenticated Key Exchange Protocols via Blockchain for Smart City

Table 1

The user data structure of the smart contracts.

Contract name	Data type	Name
Contract I	address	user
	string	PK
	string	ID
	uint	timestamp
	mapping(address string)	r
	mapping(address string)	sig
Contract II	address	user
	string	PK
	string	ID
	uint	timestamp
	string	c
Contract III	address	user
	string	PK
	string	ID
	uint	timestamp
	string	token1
	string	token2
	string	c