The year was 1637, and Georg Baresch, an alchemist and renowned collector of antiquities based in Prague, had a baffling mystery on his hands. For years now, he had been in possession of a most unusual item: a bizarre manuscript filled with strange imagery of plants, astrological diagrams, curious structures, human figures, and a range of other curiosities.
This “Sphinx,” as Baresch characterized it, was so strange that it prompted him to reach out to the Jesuit scholar Athanasius Kircher, known for his success in deciphering ancient Egyptian hieroglyphs, with hopes of obtaining information that might lead to a breakthrough in solving the mystery of the puzzling manuscript.
Today, the same bizarre treatise first obtained by Baresch in the seventeenth century is known throughout the world as the Voynich Manuscript, and despite the efforts of many since Baresch’s time who have sought to decode it, the document still refuses to give up its secrets. After more than a century of scrutiny, no one has convincingly explained who wrote it, what it says, or even whether its text carries any real meaning at all.
However, new research may finally offer scholars a fresh perspective on this confounding mystery. According to a recent peer-reviewed study, while the mystery of the Voynich Manuscript endures, a new theory strengthens the possibility that the text in a document often referred to as “the most mysterious book in the world” may have once served as a cipher system.
The hypothesis, detailed by researcher and science journalist Michael A. Greshko in the journal Cryptologia, indicates that the famous manuscript bears qualities that seemingly match the technological capabilities of scholars in the Middle Ages, potentially helping to reframe questions about the manuscript that have long perplexed researchers.
The Enduring Enigma of the Voynich Manuscript
Over the years, a range of theories has emerged as to what the purpose behind the Voynich Manuscript may be. One involves the notion that the manuscript could represent glossolalia—the purported phenomenon of speaking unknown languages, generally within the context of religious worship—or even more simply, purely unintelligible words that might have served as part of some form of fraudulent medieval operation.
Other theories hold that the Voynich Manuscript may represent an artificial language which does nonetheless conveys some sort of meaning, or that the language in the manuscript may be a legitimate unknown earlier language that its unknown author attempted to document.
However, another possibility involves the possible use of a cipher—one which may incorporate elements of a well-known language such as Italian, German, or even a “dead” language like Latin that is still widely known.
A portion of the famous Voynich Manuscript, which conveys information related to the healing properties of bathing in medicinal springs. The complete information conveyed in this portion of the text, as with the broader manuscript, remains undeciphered (Image Credit: Public Domain).
For Greshko, the notion of the Voynich Manuscript as a ciphertext seemed the most appealing, since this approach offers potential avenues toward unraveling its more unusual properties with languages that would have been in use and potentially known to its prospective author(s) in the 15th century. Ultimately, Greshko’s efforts toward unraveling the mysteries of the Voynich Manuscript (VMS) culminated in a fundamental question.
“Is it possible to make a substitution cipher—the most advanced type of cipher available in early 15th-century Europe—that can often create VMS-like ciphertext?” Greshko asks in his recent Cryptologia paper.
Finding answers to this query led Greshko to the development of a method his study calls the “Naibbe cipher,” named after a medieval Italian card game. As opposed to trying to decode the manuscript outright, as has been attempted countless times in the past, Greshko’s cipher works in reverse by transforming ordinary Latin or Italian text into strings of glyph-like symbols resembling the manuscript’s unique language, known to scholars as “Voynichese.”
The system outlined by Greshko employs the substitution of short letter fragments with structured lookup tables, and then, going beyond the use of text alone, introduces elements of randomness with the use of objects that were widely available in 15th-century Europe, such as dice and playing cards.
Intriguingly, the resulting use of the Naibbe cipher produces outputs that Greshko says mirror several of the Voynich Manuscript’s idiosyncrasies, such as patterns in symbol frequency, similarities to typical word lengths that appear in the original text, and positional behaviors that can be associated with certain glyphs in the manuscript.
Additionally, Greshko’s method appears to preserve partial traces of the underlying language, albeit through the recurrence of micro-sequences, and even though no single glyph can be cleanly mapped onto any specific plaintext letters.
Cipher Hypothesis Remains Viable
For Greshko, all this taken together strengthens the case for the cipher hypothesis, and strongly points to the use of a sophisticated method that would have significantly exceeded conventional substitution ciphers of the period.
Still, Greshko says alternatives cannot be ruled out, such as the notion that the manuscript actually could represent some kind of unknown language—whether that be a language that is now lost to history, which the author of the Voynich manuscript sought to preserve, or possibly some form of invented writing system that might have served a unique purpose.
Greshko also concedes that “in its current form, the Naibbe cipher fails in several major ways,” adding that due to its current limitations, “the Naibbe cipher invites future analysis to address whether and how modifications to the cipher’s general structure can achieve a more complete replication of VMS properties.”
Nonetheless, what Greshko’s work fundamentally succeeds in demonstrating is that a hand-executable cipher—one the likes of which could have been achieved centuries ago when the Voynich Manuscript is believed to have been produced—can indeed reproduce many of its statistical traits. This potentially important work helps to refine questions that will no doubt benefit future efforts toward unraveling “the world’s most mysterious book” by helping to narrow the range of plausible explanations.
Further, the new study provides a clearer framework for understanding how such a baffling text might have been constructed, and why it continues to defy simple explanation more than 500 years after it was written.
Greshko’s paper, “The Naibbe cipher: a substitution cipher that encrypts Latin and Italian as Voynich Manuscript-like ciphertext,” appeared in Cryptologia on November 26, 2025.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.