function keyretriver()
	idserver = rondanet.lookup("babanque", "server")
	local messagea = {action = "keyretrive"}
	textutils.serialize(messagea)
	rondanet.send(idserver, messagea)
	local disable = true
	while disable do
		local si, mess, distance = rondanet.receive()
		if si == idserver then
			publickey = mess
			return publickey
			disable = false
		end
	end
end