Hidden data embedded in electronic public records must be disclosed under Arizona's public records law, the state Supreme Court ruled Thursday in a case that attracted interest from media and government organizations.

The Supreme Court's unanimous decision overturned lower courts' rulings and is one of the first decisions by a state appellate court on whether a public records law applies to so-called "metadata" — data about data.

Metadata can show how and when a document was created or revised and by whom. The information isn't visible when a document is printed on paper nor does it appear on screen in normal settings.

"It would be illogical, and contrary to the policy of openness underlying the public records law, to conclude that public entities can withhold information embedded in an electronic document, such as the date of creation, while they would be required to produce the same information if it were written manually on a paper public records," Justice Scott Bales wrote.

A Washington state appellate court ruled last year that metadata in e-mail received by a city's deputy mayor was a public record under Washington's public records law.