The parts of the web containing data not publicly indexed or whose access is protected through anonymous networks. It is believed that about 80% of the contents present today on the world wide web are hidden in these parts.
SOURCE: The future of Cybersecurity in Italy: Strategic focus areas Projects and Actions to better defend our country from cyber attacks Laboratorio Nazionale di Cybersecurity CINI - Consorzio Interuniversitario Nazionale per l’Informatica