Paper: Cipher Type Detection

ACL ID D14-1185
Title Cipher Type Detection
Venue Conference on Empirical Methods in Natural Language Processing
Session Main Conference
Year 2014

Manual analysis and decryption of enci- phered documents is a tedious and error prone work. Often?even after spend- ing large amounts of time on a par- ticular cipher?no decipherment can be found. Automating the decryption of var- ious types of ciphers makes it possible to sift through the large number of en- crypted messages found in libraries and archives, and to focus human effort only on a small but potentially interesting sub- set of them. In this work, we train a clas- sifier that is able to predict which enci- pherment method has been used to gener- ate a given ciphertext. We are able to dis- tinguish 50 different cipher types (speci- fied by the American Cryptogram Associ- ation) with an accuracy of 58.5%. This is a 11.2% absolute improvement over the best previously published clas...