Dorabella unMASCed – the Dorabella Cipher is not an English or Latin Mono-Alphabetical Substitution Cipher

Abstract

The Dorabella cipher is an unsolved cipher with only 87 characters. In this study we show that state-of-the-art algorithms are able to solve Mono-Alphabetical Substitution Ciphers with 87 characters with a decipher rate of up to 98.7% for English and 98.6% for Latin. The same algorithms fail to find a solution to the Dorabella cipher. Furthermore, we consider simple permutations of the Dorabella cipher and attempt to solve the cipher after these are applied, but with no success. This indicates that the Dorabella cipher is unlikely to be a MASC.