The special counsel investigation of Russia’s interference in the 2016 presidential election has kicked up millions of pages of documents, much of it so sensitive that prosecutors don’t want to see it flying around the web.

In criminal cases, protective orders—one measure to restrict the dissemination of information beyond the lawyers who are directly involved—are fairly common. The protective orders in more-sensitive cases—like the Russia-related prosecutions, led by Special Counsel Robert Mueller III—have included extra measures to keep information secure.