Clustering and Categorization Applied to Cryptanalysis
Claudia Oliveira, José Antônio Moreira Xexéo, Carlos André Rodrigues de Carvalho · Cryptologia · 2006
This article presents a new application for Information Retrieval techniques. We introduce the use of clustering and categorization in the attack of cryptosystems. In order to clearly present the fundamentals and understand the workings and the implications of this new technique, we developed a procedure for keylength determination in the process of cryptanalysis of polyalphabetic ciphers, the core of any attack of this type of ciphers. The basic premises are: first, a cryptogram is a normal document written in an unknown language; secondly, Information Retrieval Techniques are extremely useful in detecting string patterns in ordinary texts and might be helpful with cryptograms as well.