Type designers have unveiled ShieldFont, a free web font designed to 'poison' AI datasets by hiding text from scrapers. Unlike Ghost Font’s optical illusions, ShieldFont uses OpenType glyph substitution to alter words in the HTML source code without changing their appearance to human readers.

The creators of ShieldFont, Seneda & Abrucio and Playtype, believe that publishing should not equate to consenting to content scraping for AI training. Their toolkit allows anyone to apply the shield to any font, making it a collective defence against unethical AI development practices.

While ShieldFont is a step forward in protecting creative work from mass scrapers, its creators acknowledge that determined attackers could potentially reverse-engineer the mapping. Nonetheless, they hope it will slow down and complicate scraping operations enough to make them less profitable.

The current v18 release targets high-frequency English nouns, with tests showing 55.8% of shielded passages no longer making the same factual claim as the original. The project’s methodology and benchmark data are available in a white paper for those interested in diving deeper into its workings.