[Tutor] how to manage an encrypted file?

[Eike Welk]

The method that Daniele describes is called encryption with a "One 
Time Pad". A somewhat readable description is in Wikipedia:
http://en.wikipedia.org/wiki/One_time_pad

This encryption method is a theoretically perfectly secure, but there 
are big organizational problems connected to its use. It 
interestingly does not require any technology. The Taliban could use 
it if they had someone with good handwriting, much patience, and a 
passion for throwing dices. 

Kind regards,
Eike.