Decryption of historical manuscripts: the DECRYPT project

Abstract

Many historians and linguists are working individually and in an uncoordinated fashion on the identification and decryption of historical ciphers. This is a time-consuming process as they often work without access to automatic methods and processes that can accelerate the decipherment. At the same time, computer scientists and cryptologists are developing algorithms to decrypt various cipher types without having access to a large number of original ciphertexts. In this paper, we describe the DECRYPT project aiming at the creation of resources and tools for historical cryptology by bringing the expertise of various disciplines together for collecting data, exchanging methods for faster progress to transcribe, decrypt and contextualize historical encrypted manuscripts. We present our goals and work-in progress of a general approach for analyzing historical encrypted manuscripts using standardized methods and a new set of state-of-the-art tools. We release the data and tools as open-source hoping that all mentioned disciplines would benefit and contribute to the research infrastructure of historical cryptology.

Deciphering three diplomatic letters sent by Maximilian II in 1575

“…It demonstrates how a combined interdisciplinary effort of historians, linguists, philologists, computer scientists, and cryptanalysts can be fruitful. The work presented here, is a direct outcome of the interdisciplinary research project DECRYPT (Megyesi et al 2020), that aims at collecting, transcribing, analyzing, and deciphering original historical encrypted manuscripts. Moreover, the tools created and used for the DECRYPT project are published and available online in order to give others with interest in historical cryptology the opportunity to decipher similar encrypted manuscripts on their own.…”

Can Sequence-to-Sequence Models Crack Substitution Ciphers?

“…Example documents include encrypted letters, diplomatic correspondences, and books from secret societies (Figure 1). Previous work has made historical cipher collections available for researchers (Pettersson and Megyesi, 2019;Megyesi et al, 2020). Decipherment of classical ciphers is an essential step to reveal the contents of those historical documents.…”

“…Libraries and archives have many enciphered documents from the early modern period. Previous work has been done to make historical cipher collections available for researchers (Megyesi et al, 2020;Pettersson and Megyesi, 2019). Decipherment of classical ciphers is an essential step to reveal the contents of those historical documents.…”

Proceedings of the 3rd International Conference on Historical Cryptology HistoCrypt 2020

“…Some research projects with focus on digital paleography, including the transcription of historical manuscripts are, for example, HIMANIS (Stutzmann et al, 2017), Transkribus (Kahle et al, 2017), and From Quill to Bytes (q2b, 2013). For the case of encrypted historical manuscripts analysis, which constitute the main subject of this paper, the project DECRYPT (Megyesi et al, 2020) is joining the expertise in computer vision, computational linguistics, philology, cryptanalysis and history for the aim of making advances in historical cryptology.…”