What sort of cyberattack is the equivalent of a traditional armed attack? Efforts to answer that question have culminated in the Manual on International Law Applicable to Cyber Warfare (also known as the Tallinn Manual), which will be published later this year, IEEE Spectrum reports.

The Tallinn Manual is a nonbinding yet authoritative restatement of the law of armed conflict as it relates to cyberwar. It offers attackers, defenders, and legal experts guidance on how cyberattacks can be classified as actions covered under the law, such as armed attacks.

“The term ‘armed attack’ has a precise meaning in international law: Not all ‘cyberattacks’ rise to the level of an armed attack,” says Bret Michael, a professor of computer science and electrical engineering at the U.S. Naval Postgraduate School, who has been serving as a technical expert to the group drafting the Tallinn Manual.

What is certain, say observers, is that going forward, conventional warfare will almost always be complemented by cyberwarfare aimed at knocking out an opponent’s communications and intelligence-gathering capabilities. “Actually, that’s already being done,” says Michael.