%0 Journal Article %1 lakowaM209_2 %A Lasry, George %A Kopal, Nils %A Wacker, Arno %D 2015 %J Cryptologia %K ciphertext cryptanalysis hagelin m-209 myown only %N ahead-of-print %P 1--36 %T Ciphertext-Only Cryptanalysis of Hagelin M-209 Messages %U http://dx.doi.org/10.1080/01611194.2015.1028683 %X The Hagelin M-209 was a mechanical encryption device used by the US Army during World War 2 and the Korean War, as well as by other armies and in embassy settings. In this paper, we present a 4-stage hillclimbing algorithm for recovering the full key settings from ciphertext only. The two first stages are based on a divide-and-conquer approach developed by G. Sullivan. In our performance evaluation, we show that our method is able to recover key settings from messages as short as 750 letters, compared to 2000 - 2500 letters with prior methods. With this method, we solved several M-209 ciphertext-only challenges, including the final exercises in W. Barker's 1977 book, Cryptanalysis of the Hagelin Cryptograph.

@article{lakowaM209_2, abstract = {The Hagelin M-209 was a mechanical encryption device used by the US Army during World War 2 and the Korean War, as well as by other armies and in embassy settings. In this paper, we present a 4-stage hillclimbing algorithm for recovering the full key settings from ciphertext only. The two first stages are based on a divide-and-conquer approach developed by G. Sullivan. In our performance evaluation, we show that our method is able to recover key settings from messages as short as 750 letters, compared to 2000 - 2500 letters with prior methods. With this method, we solved several M-209 ciphertext-only challenges, including the final exercises in W. Barker's 1977 book, Cryptanalysis of the Hagelin Cryptograph.}, added-at = {2015-02-11T14:09:22.000+0100}, author = {Lasry, George and Kopal, Nils and Wacker, Arno}, biburl = {https://www.bibsonomy.org/bibtex/2121bbd3e1580d4f51c78f0e65a7fa481/niko}, interhash = {da4ac40b0bb1e5c1f8cc0ad2ad7bc15c}, intrahash = {121bbd3e1580d4f51c78f0e65a7fa481}, journal = {Cryptologia}, keywords = {ciphertext cryptanalysis hagelin m-209 myown only}, number = {ahead-of-print}, pages = {1--36}, timestamp = {2015-10-07T19:15:05.000+0200}, title = {Ciphertext-Only Cryptanalysis of Hagelin M-209 Messages}, url = {http://dx.doi.org/10.1080/01611194.2015.1028683}, year = 2015 }