[Wurlitzer]

"But all codes are eventually suceptible to brute force attacks.) "

You may be right Redcloak but to my knowledge, the method I described has not been broken without one of the parties giving up the book.

[Redcloak]

It's very secure. However, if one has the resources of an unlisted government agency and a basement full of Cray computers at their disposal, even one time pads can be beaten. A defense would be to encrypt garbage along with the "good stuff". This wastes "Agent Smith's" valuable computer time decoding things like grocery shopping lists and your 5-year old's poetry.