Experimental Analysis of the Dorabella Cipher with Statistical Language Models

Abstract

The Dorabella cipher is a symbolic message written in 1897 by English composer Edward Elgar. We analyze the cipher using modern computational and statistical techniques. We consider several open questions: Is the underlying message natural language text or music? If it is language, what is the most likely language? Is Dorabella a simple substitution cipher? If so, why has nobody managed to produce a plausible decipherment? Are some unusual-looking patterns in the cipher likely to occur by chance? Can stateof-the-art algorithmic solvers decipher at least some words of the message? This work is intended as a contribution towards finding answers to these questions.

Proceedings of the 4th International Conference on Historical Cryptology HistoCrypt 2020

“…The results of the present study comport with other recent analyses of the Dorabella cryptogram. Schmeh (2018) concluded that "frequency count and the contact counts of the Dorabella Cryptogram are consistent with the English language," and Hauer et al (2021) reported "evidence for English as the language of the cipher" from n-gram language models, and that "the occurrence of several pairs of mirrored symbols is unlikely to be due to chance, suggesting that Dorabella is not a hoax." Still, no convincing MASC solution to the Dorabella cryptogram has yet been found, even using modern, state-of-the-art algorithms with high decipherment rates (Wase, 2023).…”