Riverbank Publications No. 20 Several Machine Ciphers and Methods for Their Solution.2nd Impression. This item is unavailable.Riverbank Publications No. 20 Several Machine Ciphers and Methods for Their Solution.2nd Impression

Second impression. [2], [1]-58, [28] pages 28.5 cm. Provided in the originally issued Riverbank Laboratories button and string flapped manila envelope with limitation number on outside. Individually numbered limitation of 200 copies (so stated on copyright page). This is the SECOND IMPRESSION, with the textblock printed on light grey paper. Stiff tan publisher's wraps with cover titles duplicating title page and hinges reinforced with linen tape (as issued). Last 28 pages comprise 'Synoptic Tables for the Star Cipher', which was also made available by Riverbank as a separate publication. SECOND impression [or printing]. This volume was also issued in a First impression [or printing]. This copy with light age staining to the wrappers and folder. Wraps. A restricted publication not publicly available when issued, it appears in a few institutional collections, but is rarely found on the market. 'Friedman amplified the de Viaris solution of the Bazeries cryptograph to which he gave the generic name of a "multiplex" system, and devised a solution for the Wheatstone cryptography, perhaps based on his work with the Pletts device.' (Kahn) Authorship attribution from Galland. [Methods and examples of Deciphering] LITERATURE: J.S. Galland, An Historical and Analytical Bibliography of Cryptology, page 68. Kahn, The CodeBreakers, 1996, p376. Shulman, An Annotated Bibliography of Cryptography, 1976, p82 (all referring to the first printing).…