Path: cactus.org!milano!radar!cs.utexas.edu!news-server.csri.toronto.edu! + bonnie.concordia.ca!clyde.concordia.ca!altitude!elevia!alain From: alain@elevia.UUCP (W.A.Simon) Newsgroups: sci.crypt Subject: Re: Braided Streams (an old hack) Message-ID: <1991Jun18.114903.11733@elevia.UUCP> Date: 18 Jun 91 11:49:03 GMT Organization: The Electronic Path - Global Village Lines: 34 I wrote MANY words about: > The Braided Stream Secure Communication System is a simple > and fast multiplexer system which provides high levels of > [ ... ] > to take the next bit to be output from, is determined by the > value of a bit, or group of bits, from the key stream. I am still convinced it is secure as you can get, but it is not as "new" as one might think. Some of us who already have a few wrinkles may remember an old trick of the cryptographer's trade, which consisted in using a perforated piece of cardboard, placed over some paper, through which one wrote a message. Then the cardboard (it was called a grid) was removed and the blanks left on the piece of paper were filled in with garbage which was designed in such a way that it incorporated the message within an innocuous text. One courrier would carry the grid, another one the paper. The courrier carrying the paper was relatively safe as the message looked inoffensive. A variation consisted of using several such grids, none of which had any of its holes overapping any other grid's perforations. However, what was gained in efficiency (longer message on one piece of paper) was lost in safety for the courrier carrying the paper (it looked suspisciously like nothing normal). The braided stream algorithm is nothing less/more than this old hack. I have not invented something completely new... but at least we can make use of it, in new ways. -- William "Alain" Simon UUCP: alain@elevia.UUCP