Michael Helm wrote: | On Mar 4, 3:09pm, Adam Shostack wrote: | > Markoff shouyld know better than this. There is a long | > history of business use of codes & ciphers, going back hundereds of | > years, and durring the heyday of the telegraph, there were fair size | > companies that created codebooks with (locally configurable) | > superencipherment systems for the market. | | I thought that, for the most part, the telegraph systems described | above were to reduce cable charges (1 code word instead of a 15-word | sentence, a huge savings in those days). Maybe it's the use to which | the encoding's put that's controversial, not the (idea of) encoding | itself. This is true, the codes were designed to minimize telegraph charges. However, many of them also contained systems (of varying quality) for protecting the privacy of communications. For example, one might buy a book without page numbers, and be encouraged to arbitrarily number the pages. A code entry would then be page indicator and position on the page. Not diplomatic quality, but considering the poor state of commercial cryptanalysis at the time, fairly effective at protecting business secrets. My copy of Kahn is on loan, so I might be misremembering things. Speaking of old crypto, I haven't heard anything on where to find a Jefferson wheel cipher. Does no one know? Adam -- "It is seldom that liberty of any kind is lost all at once." -Hume