Re: Crypting files with Ada

[Adrian Knoth <adi@drcomp.erfurt.thur.de>]

Preben Randhol <randhol+news@pvv.org> wrote:

>> So take your glibAda and call unlink(filename); Or even better
>               ^^^^^^^
>               what is this?

This is inexistend. Unfortunately. It is ment like 'glibc', but only
for Ada.

The library should implement remove() on top of the Kernel-API in Ada.

Another approach (which I don't like) would be a more or less direct
binding to glibc, so to say "Pragma Import" all the time.

> The problem is that if you simply delete a file in say Windows or Linux 
> you don't rease it you only delete the link. 

Right.

> So unless the OS has overwritten the place the file occupied with new 
> files one can recover it.

Yes. This is why someone intended wipe:

Description
       The  wipe  command  reads each file in sequence and writes
       over the file with nul characters.  If the  -i  option  is
       given,  it prompts the user before wiping the file.  If -d
       is given, it removes each  file  after  writing  over  it.
       (The default behavior is just to write over it.)  If -v is
       given, wipe will print the version number.

You may have a look at the source or re-implement it on your own. It
doesn't sound too difficult.
 
> I guess one could change every byte in the file with 0 and then write
> the file again before deleting it.

Better read from /dev/random :) And do multiple passes in order to
destroy remaining magnetization.


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