The ZXX font is designed to be difficult for machines to read. Former National Security Agency contractor Sang Mun created the font as a response to increasing government incursions on privacy. "I have become dedicated to researching ways to 'articulate our unfreedom' and to continue the evolution of my own thinking about censorship, surveillance, and a free society," he explained after releasing the font online in June.

Several different techniques are used to baffle digital scanners, including camouflage patterns drawn from nature, crowding the letters with digital noise, and simply crossing out each letter. The font is named after the Library of Congress code ZXX, which labels a document as containing "no linguistic content." The goal is to make the contents of a document unreadable by text scanning software while still being intelligible to a human reader.

Part awareness-raising art project, part useful tool, the font only works to protect the contents of attachments or other items that can be transmitted as images. Though it's unclear how important optical text recognition is in government snooping, every bit of extra privacy counts.