An
illegal number is a
number that represents information which is illegal to possess, utter or propagate. Any information that can be represented in binary format is,
ipso facto, representable as a number, and therefore if the information itself is illegal in some way, the pure number itself may be illegal.
To date, the idea of a number being illegal has not been tested in the courts.
An illegal number may represent some type of
classified information or
trade secret, legal to possess only by certain authorized persons. An
AACS encryption key that came to prominence in
May 2007 is an example of a number claimed to be a secret, and whose publication or inappropriate possession is claimed to be illegal in the United States. It allegedly assists in the decryption of any
HD DVD or
Blu-ray Disc released before this date. The issuers of a series of cease-and-desist letters claim that the key itself is therefore a copyright circumvention device, and that publishing the key violates Title 1 of the American
Digital Millennium Copyright Act.
In part of the DeCSS court order
and in the AACS legal notices, the claimed protection for these numbers is based on their mere possession and the value or potential use of the numbers. This makes their status and legal issues surrounding their distribution quite distinct from that of mere
copyright infringement.
Any image file or an executable program can be regarded as simply a very large binary number. In certain jurisdictions, there are images that are illegal to possess, due to obscenity or secrecy/classified status, so the corresponding numbers could be considered illegal.See also
