Apparently the NSA is in the business of subversive type design — or at least they have someone on staff who dabbles in it. Below is a video about ZXX, a set of letterforms that foil optical character recognition while preserving some level of legibility to human readers.
We’ve come a long way since the first typefaces intended specifically for human-machine inter-intelligibility. Adrian Frutiger undertook the commission for OCR-B with the intention of creating a reliable OCR font that was at least “inoffensive” to human readers.
Another typeface formed barcodes into the shape of letters.
Magnetic-ink faces like E13-B — which were designed to automate banking in the 1960s — are in fact still used on checks and credit cards.
All of these were pioneering attempts to bridge the gap between human and machine visuality. But the gap is now so narrow, practically overlapping at times, that letterforms must now be designed to deliberately subvert OCR in certain circumstances.