[fpc-other] disk "glasses"

[Sven Barth]

On 12.08.2014 22:56, duilio foschi wrote:
> I successfully use TrueCrypt in order to protect my source code.
>
> TrueCrypt creates a password protected crypted disk in my PC.
>
> I can freely leave my PC unattended: nobody will be able to steal my code.
>
> However when my PC is connected to a net, I cannot be so confident.
>
> In fact when the crypted disk is mounted by windows, everybody
> connected to my PC can read (and possibly steal) disk data.
>
> I wonder if some software product X exists where the a crypted disk is
> NOT mounted by the OS but _by the application_
>
> 2 applications using X should be able to concurrently read/write dato
> from/to the crypted disk.
>
> Any application not using X should see only a fixed size (2GB?) file.
>
> Does this product exist ?
>
> It should be possible to use it from a pascal or delphi application.

In theory something like this could exist (I'm not aware of anything for 
TrueCrypt protected files), but having two or more applications that 
concurrently write to a single file is a bad(TM) idea. Imagine both 
applications want to write to the end of the file at the same time. 
Which application's content will then be in the file? Maybe that of the 
first one. Maybe that of the second one. Maybe a mix of both. Especially 
in the last case you can consider the file corrupted. If two or more 
applications should access a file in a writeable manner they should go 
trough a third "service" which controls accesses and writes to the file 
(like is usually done with e.g. databases). And simply spoken the OS is 
such a kind of service (though its not running as a separate process per 
se). Another possiblity would be to have a real service...

A little bit more on the topic of "world writable files": 
http://blogs.msdn.com/b/oldnewthing/archive/2004/11/22/267890.aspx

Regards,
Sven