ubuntu: destroy a huge binary file and make it non-readable.

[Nils Kassube]

Nandakumar wrote:
> >> I'd like to point out that the statement "even the developer can't
> decrypt it" is meaningless.
> The encryption algorithm simply depends on the key. The key is not
> recorded while encryption too. The source code is also open. And if
> you read it, you will understand that the only way to hack is trial
> and error method. The success of encryption depends on the length and
> strength of the key.

Sorry, but I can't see the source code at the URLs you provided: 
<http://nandakumar.co.in/private/filedest> or 
<https://launchpad.net/gopanam/+download>. But maybe I'm missing 
something?

Anyway, I don't dispute that the encryption works. But it doesn't matter 
if the key is recorded or not. If the output is not sufficiently random, 
there may be ways to decrypt it even without knowing the key.

To explain why I criticize your statement, let's think of an example:
If I would write an encryption program where I use the wellknown Caesar 
cipher (*), the output may be unreadable for me and any other normal 
person. Therefore I could state that "the developer can't decrypt the 
output without the key", but that doesn't mean that there aren't smarter 
people than me who easily decipher the output using some statistics and 
knowledge of character distribution in normal languages.

As we don't know about the data the OP wants to "destroy", we don't know 
if the use of a simple encryption like my example might be good enough 
or if something better is needed. Therefore the statement that "I can't 
decrypt the output" does not necessarily mean that my program is useful, 
i.e. the statement is meaningless. And by pointing out that the 
statement is meaningless I merely wanted to give the OP a hint that this 
should not be a base for the decision to use the program.


Nils

(*) The Caesar cipher simply shifts the characters of the alphabet a 
fixed amount of places, which makes the new alphabet e.g. 
"cdefghijklmnopqrstuvwxyzab" instead of the normal sequence starting 
with "a".