Comment by jcynix
>where do you keep secret.txt exactly?
Hidden. Encrypted. And the passphrase is: at 5,21 which is the 5th line on page 21 of your favorite book. Which you have more than one copy of, because you like it that much. And you need copies to lend. Or you have the PDF from Gutenberg.org?
And 5/21 might be the birthday of your first child, or your wedding day, or whatever?
It might be a favorite quote, like "Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety." Augmented by the above date if needed?
Hidden where? Are you writing it on a post-it and putting it on top of your screen? Are you keeping it in your wallet? In a safe? What if you lose it or your house is flooded?
> And 5/21 might be the birthday of your first child, or your wedding day, or whatever?
How sure are you that you'd remember all that scheme for 20 years? How about 50 years? Some documents may be relevant for a very long time. What about if you need more than one key? What about if you need to give access to one document to specific set of persons?
Once you consider all the scenarios that can happen through a lifetime, you start to understand why managing all those complexities correctly is not trivial. And that's why people pay third parties to do it for them. It's not because encrypting a bag of bytes is hard. It's because of all the things that surround it.