On Jul 6, 2014, at 9:21 AM, Richard Damon <rich...@damon-family.org> wrote:
> On 5/21/14, 12:42 PM, Nagy László Zsolt wrote:
>> I need to create an application for Windows 7 that runs from a flash
>> drive. This program would be used to create remote backups of the
>> pendrive. The pendrive contains sensitive data, so when I plug in the
>> pendrive and run the program to make a backup, it should not leave any
>> trace of operation on the windows system. The information is so
>> sensitive that I was forbidden to use cloud storage. I was also
>> forbidden to make backups to a local drive, or leave any trace on the
>> host windows system.
>> The question is this: if I create this program with Python 3.4 and
>> cx_Freeze, then what should I expect. When the user starts the
>> cx_freeze-d program from the flash drive, will it create temporary files
>> on the system drive? Will it leave log files or store any permanent or
>> temporary data on the system drive (maybe in the user's tmp folder) that
>> can later be used to tell what drive was mounted, with what parameters
>> the program was started etc.
> I am not sure about what temp files python might leave around, but if you are
> being ultimately paranoid about this, one risk that will be present is the
> possibility of leaving traces of data in the swap file. If the program
> doesn't specifically prohibit it, anything that is brought into memory (and
> the act of reading the pendrive will do this) might end up in the swap file.
> I can't imagine python having a run time option to force it to disable the
> swap file.
> If the data is as sensitive as they seem to want to treat it, perhaps you
> should follow the procedures of classified computing, which says that any
> storage medium "exposed" to classified computing becomes classified. This
> would say that you would use a dedicated machine to do these backups, and
> after doing them, you remove the hard disk from the machine and lock it up,
> only to be taken out for later backups. This level of paranoia says you don't
> need to be as concerned about figuring out what traces might be left, you
> assume they are and lock them up.
Furthermore, I don’t know about Windows, but on many UNIX-like OSs, the file
system preserves the time the file was last accessed. If the goal is truly to
leave no traces of the fact that the a group of files was backed up, this
pretty well would be a red flag that they had been.