Thank you for putting such interesting and useful electric circuits, and descriptions of how they work, on the web.
I hope you won't be too disappointed when I tell you that The ELK Theory - Unbreakable Encryption is the same as "one-time pad" encryption http://en.wikipedia.org/wiki/One-time_pad . Apparently the one-time pad was invented and patented around 1920 .
Rather than use "+" while encrypting and "-" while decrypting, I find it simpler to use the same operator in both directions. (So "double encrypting" with the same keyword gives me the plaintext back -- I don't need a "encrypt/decrypt" switch on the machine). The Beaufort cipher uses "-" in both directions. The original one-time pad used "XOR" in both directions. (Is there any other operator that does not require a "encrypt/decrypt" switch?) -- David Cary (DAV-MP-E62a) ON 20061101@6:35:14 AM at page: http://techref.massmind.org/techref/member/RB-ezy-Q33/index.htm# David A Cary[DAV-MP-E62a] edited the page. Difference: http://techref.massmind.org/techref/diff.asp?url=H:\techref\member\RB-ezy-Q33\index.htm&version=6