Strip ciphers were essentially flattened out versions of the Bazeries Cylinder. They consisted of several flat narrow strips of paper arranged parallel to one another, bearing the letters of the alphabet in a scrambled order. The plaintext was arranged in a column by sliding the strips sideways, and any of the other rows could be taken as the cipher text. This strip-cipher was used extensively by the US during World War II, a time when there was a shortage of crypto-machines.
The M-138 was a strip cipher devised by Colonel Parker Hitt and the US Army adopted it as the M-138A and the US Navy employed it under the name CSP-895. The British also used a strip cipher device called SYKO/S.D.2 Strip Cipher.
- M94 - Wikipedia article
- Photos published with permission from Prof. Gessler:
- http://www.sscnet.ucla.edu/geog/gessler/collections/crypto-m138a1.jpg and http://www.sscnet.ucla.edu/geog/gessler/collections/crypto-m138a2cu.jpg