Transcription of Historical Ciphers and Keys

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.