Piracy consists of any of the following acts:

  • a. any illegal acts of violence or detention, or any act of depredation, committed for private ends by the crew or the passengers of a private ship or a private aircraft, and directed:
    • i. on the high seas, against another ship or aircraft, or against persons or property on board such ship or aircraft;
    • ii. against a ship, aircraft, persons or property in a place outside the jurisdiction of any State;
  • b. any act of voluntary participation in the operation of a ship or of an aircraft with knowledge of facts making it a pirate ship or aircraft;

any act of inciting or of intentionally facilitating an act described in subparagraph (a) or (b).

UNCLOS : http://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf