Some signals carry encryption and specify use conditions (such as "may not be recorded" or "may not be viewed on displays larger than 1 m in diagonal measure") backed up with the force of law under the WIPO Copyright Treaty and national legislation implementing it, such as the U.S. Digital Millennium Copyright Act.
WIPO | Treaty of Versailles | copyright | Digital Millennium Copyright Act | Treaty of Trianon | copyright infringement | Treaty of Utrecht | Treaty of Aix-la-Chapelle | Treaty of Berlin (1878) | Treaty of Rome | Treaty of Lisbon | Treaty of Campo Formio | Treaty of Berlin | Treaty of Aix-la-Chapelle (1748) | Maastricht Treaty | Copyright Act of 1976 | Treaty of the Pyrenees | Treaty of Saint-Germain-en-Laye (1919) | Treaty of Guadalupe Hidalgo | Penn Treaty Park | Lateran Treaty | Copyright law of New Zealand | Copyright infringement | Copyright | Washington Naval Treaty | Treaty of San Stefano | Treaty of Roskilde | Treaty of Nice | Treaty of Frankfurt | Treaty of Brest-Litovsk |