This repository contains code and datasets associated with the paper:
Greshko, Michael A. (2025). The Naibbe cipher: a substitution cipher that encrypts Latin and Italian as Voynich Manuscript-like ciphertext. Cryptologia. https://doi.org/10.1080/01611194.2025.2566408
In the work represented here and in the associated study, I investigate the hypothesis that the Voynich Manuscript (MS 408, Yale University Beinecke Library) is compatible with being a ciphertext by attempting to develop a historically plausible cipher that can replicate the manuscript’s unusual properties. The resulting cipher—a verbose homophonic substitution cipher I call the Naibbe cipher—can be done entirely by hand with 15th-century materials, and when it encrypts a wide range of Latin and Italian plaintexts, the resulting ciphertexts remain fully decipherable and also reliably reproduce many key statistical properties of the Voynich Manuscript at once. My results suggest that the so-called “ciphertext hypothesis” for the Voynich Manuscript remains viable, while also placing constraints on plausible substitution cipher structures.
Additional datasets, including the original Microsoft Excel implementations of the Naibbe cipher and Voynichesque, can be found at: https://doi.org/10.5281/zenodo.16415087
Extensive discussion of a preprint version of this paper can be accessed at: https://www.voynich.ninja//thread-4848.html
Unless otherwise indicated, the source code contained in this repository is provided under the modified MIT license below.
Copyright (c) 2025, Michael A. Greshko.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software, datasets, and associated documentation files (the "Software and Datasets"), to deal in the Software and Datasets without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software and Datasets, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
- The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software and Datasets.
- Any publications making use of the Software and Datasets, or any substantial portions thereof, shall cite the Software and Datasets's original publication:
Greshko, Michael A. (2025). The Naibbe cipher: a substitution cipher that encrypts Latin and Italian as Voynich Manuscript-like ciphertext. Cryptologia. https://doi.org/10.1080/01611194.2025.2566408
THE SOFTWARE AND DATASETS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE AND DATASETS.