Cryptanalysis of Chaocipher and solution of Exhibit 6

@article{Lasry2016CryptanalysisOC,
  title={Cryptanalysis of Chaocipher and solution of Exhibit 6},
  author={George Lasry and Moshe Rubin and Nils Kopal and Arno Wacker},
  journal={Cryptologia},
  year={2016},
  volume={40},
  pages={487-514}
}