'World's Most Mysterious Book' Might Be Decoded With a Cipher

A medieval manuscript that has stumped codebreakers for more than a century may have been produced with something as simple as cards and dice, according to a new study. Science journalist Michael Greshko has devised a cipher system, dubbed "Naibbe" after a 14th-century Italian card game, that breaks up Latin or Italian words into single or double letters using rolls of a die, then determines how to convert the letters into glyphs using draws from a deck, per Live Science. The resulting "mock-Voynichese" text, he reports in the journal Cryptologia, closely mimics the look and statistical behavior of the script found in the 15th-century Voynich manuscript, though it does not decode it.

The Voynich manuscript—about 38,000 words of unknown glyphs accompanied by illustrations of plants, astrological diagrams, and nude women in baths—is dubbed "the world's most mysterious book," per WION. It has long divided experts over whether its text encodes a real language or is an elaborate hoax. Modern decryption attempts, including those using artificial intelligence, have repeatedly failed, bolstering the hoax theory. Yet Naibbe reproduces several key features of "Voynichese," including how often certain symbols appear, typical word lengths, and some apparent grammatical patterns, suggesting that a similar hand-executable cipher could have generated the original text.

Greshko stresses his method is almost certainly not the manuscript's actual recipe, but rather a proof of concept that such a system is plausible with medieval technology. Former satellite engineer and Voynich specialist René Zandbergen, who was not involved in the research, called the work a valuable demonstration that a structured cipher can yield Voynich-like text, while emphasizing it doesn't resolve whether the manuscript is meaningful or nonsense. Greshko hopes Naibbe will serve as a benchmark for future computational studies, with differences between his output and the real manuscript potentially offering fresh clues about how the mysterious book was created.