The Wall Street Journal has a column called "My tech essentials" where various famous people write about how they use technology in their everyday lives. Rian Johnson, director and scriptwriter of Star Wars: The Last Jedi, recently wrote such.
Rian Johnson reveals in his column that he wrote the entire first draft of the film's script on a Macbook Air that had no installed programs and was never connected to any network. He carried it with him almost everywhere and locked it in a safe in the Pinewood studio when, for example, he was to go home and sleep.
How he did with backup can not be seen by the column.
During filming, Rian Johnson thinks about photography, and he did it during the production of The Last Jedi. But for safety, so no images could leak through a hack, he used a Leica M6 and hundreds of rolls of black and white film.