Beomsik Song Huaxiong Wang Jennifer Seberry A New Cryptanalytic Method Using the Distribution Characteristics of Substitution Distances. 18-31 2001 conf/icisc/2001 ICISC http://link.springer.de/link/service/series/0558/bibs/2288/22880018.htm db/conf/icisc/icisc2001.html#SongWS01