-----BEGIN PGP SIGNED MESSAGE----- Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit To: sjohnson@packetengines.com, cypherpunks@toad.com Date: Wed Sep 18 23:06:32 1996

i've been on cypherpunks for about a year a half now, and have wacthed many interesting threads pass by but i've never posited anything. what has brought me out into the open is this : i work for an engineering firm doing asic design, i use pgp ( as do all rational persons ), a co-worker here has come up with a 'cypher' scheme that he would like to use to send code to our clients. the scheme is this : he would take the file of code and pad all lines to the length of the longest line, he would then preform column swaps, and then row swaps, to 'mix up' the file. the person receiving the file would then preform the opposite functions to recover the file. it seems so simple that it can't be good. i've convenced him to use pgp, but i would like some input if possible on why his cypher scheme is not a good one.

thanx

Okay... well, in order to undo whatever was done (the column swaps and row swaps, and the pads), the formula has to be transmitted. Assuming that someone can intercept that as well as the alleged cyphertext, it's no-good. It's the whole "secure channel" issue. (Also, some information would have to be attached to the file containing the orignial end-of-lines for each line, or the padding will be difficult to tell from the legitimate code.) dave - ----- David E. Smith, P O Box 324, Cape Girardeau MO USA 63702 dsmith@prairienet.org http://www.prairienet.org/~dsmith send mail with subject of "send pgp-key" for my PGP public key "The world's at stake. Don't confuse me with details." -- Captain America, "Onslaught" ... famous last words -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQEVAwUBMkDGyzVTwUKWHSsJAQHD3Af9H+Vq4qFnv9JWPY0E7x8zuXM4Om3zGZ2O sQYKOR/zAZ6qXLA8a9/C//yMPzRIVf0msd/fytt1PDB+Ei2t7+87EIOjETEwGtOp hmpioj0IUkYwxAvVV7Ihmw+6bxKCGPolxHekPyjfdI58eZt/aAzh8tcS9X4htxGH DzgKBm/OEZwMa1PulRWYQdDQmQCN9Cgno87RJn+e1kvE8wgrhYaLy5TOZKl99Vpb LgXj+CAbMm7WkXZT52scIX/hkcjbMxIEilYX7HfdIFKg7yv3O9ioeba14szafqPd KOU2DNL1rLA+yHUm0jnNQ6SugnMHRey5/hRq2XSBAyaK4IRagCkslw== =g6AI -----END PGP SIGNATURE-----