[Retracted] Enabling Decentralized and Auditable Access Control for IoT through Blockchain and Smart Contracts

Algorithm 2

Capability smart contract.

	contract capability:
	register(token):
	// verify if the policy exists
	if ! exist(hash(token)) then
	token.status = “active”
	put(token)
	store(token)
	return true
	else
	return false
	end if
	query(token):
	get(token)
	if error != nil then
	return error
	else
	status = token.status
	return status
	end if
	generate(issuer, privkey, user, device, resource, action):
	time = get(current_system_time)
	id = get(random_ID)
	sig = sig_func(privkey, id, time, issuer, user,
	device, resource, action)
	token = JSON(id, time, issuer, user, device,
	resource, action, sig)
	register(token)
	return token
	revoke(token):
	get(token)
	if error != nil then
	token.status = “inactive”
	return true
	else
	return false
	end if