Transcription of Historical Ciphers and Keys

Abstract

Historical ciphertexts and keys contain a wide range of symbols from digits and letters from known alphabets to various types of graphic signs. To be able to study ciphertexts and keys empirically in large(r) scale, consistent representation of the symbol systems used in ciphers is inevitable. In this paper, we present guidelines for transcription of ciphertexts, keys and cipher-related cleartext documents. We hope that the guidelines contribute not only to the systematic and consistent text representation across ciphertexts and keys, but also help in more accurate and reliable transcriptions.

Deciphering three diplomatic letters sent by Maximilian II in 1575

“…For each ciphertext symbol, we chose a different UTF-8 letter to represent it. We transcribed cleartext passages with the syntax defined in the DECRYPT transcription guidelines (Megyesi 2020).…”

HCPortal Modules for Teaching and Promoting Cryptology

“…The second project is a special client-server application that can be used to digitize and store (historical) nomenclator keys. Compared to the DE-CODE database (Megyesi, 2020), (Megyesi et al, 2020), we store less meta-data, but some new additional information, like the nomenclator structure described with our own scheme 6 . We created a notation to describe the nomenclator scheme.…”

“…The scheme also describes the graphical structure of the key 7 . We adopted the cipher symbol representation from Megyesi (2020). After the analysis of our nomenclator keys, we had to modify and extend this structure.…”

Solving a Tunny Challenge with Computerized "Testery" Methods

“…The transcription guidelines presented in this paper constitute a summary of a detailed set of guidelines for encrypted sources, presented in (Megyesi, 2020) with many illustrations and examples. The guidelines have been applied to the transcription of several hundred of encrypted manuscripts and stored in the DECODE database (Megyesi et al, 2019).…”

“…After the metadata, the actual transcription of the content of the keys follows. The transcription guidelines for keys are partly based on the master thesis of Tudor (2019) and the transcription guidelines for ciphers (Megyesi, 2020). For keys, the same principles apply as for ciphertexts, when it comes to symbols described in Section 3.2.2, and cleartext sequences, which often contains explanations about the cipher key and explained in Section 3.2.5.…”