Protecting Location Privacy in IoT Wireless Sensor Networks through Addresses Anonymity

Algorithm 1

	if node is sender then
	Key[a- > b] ← 0xFFFFFFFF;
	if node has frame to be transmitted then
	IDS[a- > b] ← HMAC(Key[a- > b], IDa);
	IDD[a- > b] ← HMAC(Key[a- > b], IDb);
	Send DATA frame { IDS[a- > b], IDD[a- > b],payload, FCS};
	Create timer Stimer with a certain timeout;
	end
	if an ACK frame is received then
	for each neighbors do
	if FCS checksum OK and IDS[a- > b] from ACK frame = = IDS[a- > b] then
	//generate new key
	Key[a- > b] ←Key[a- > b] ⊕ Hash(payload);
	//generate new addresses
	IDS[a- > b] ←HMAC(Key[a- > b], IDa);
	IDD[a- > b] ←HMAC(Key[a- > b], IDb);
	kill timer Stimer;
	end
	end
	end
	if Stimer timeout then
	Send DATA frame { IDS[a- > b], IDD[a- > b],payload, FCS};
	end
	end
	if node is receiver then
	Key[a- > b] ← 0xFFFFFFFF;
	IDS[a- > b] ← HMAC(Key[a- > b], IDa);
	IDD[a- > b] ← HMAC(Key[a- > b], IDb);
	IDSo[a- > b] ← HMAC(Key[a- > b], IDa);
	IDDo[a- > b] ← HMAC(Key[a- > b], IDb);
	if a DATA frame is received then
	for each neighbor do
	if FCS checksum OK and IDD[a- > b] from frame = = IDD[a- > b] then
	//save old addresses
	IDSo[a- > b] ← IDS [a- > b];
	IDDo[a- > b] ← IDD [a- > b];
	//generate new key
	Key[a- > b] ←Key[a- > b] ⊕ Hash(payload);
	//generate new addresses
	IDS[a- > b]<-HMAC(Key[a- > b], IDa);
	IDD[a- > b]<-HMAC(Key[a- > b], IDb);
	deliver frame to upper layer;
	send ACK frame { IDDo[a- > b], IDSo[a- > b], FCS};
	else if FCS checksum OK and IDD[a- > b] from frame = = IDDo[a- > b] then
	//DATA frame already delivered
	send ACK frame { IDDo[a- > b], IDSo[a- > b], FCS};
	end
	end
	end
	end