In order to offer better protection to the files you encrypt, CZIP X can delete original files.
You have two choices:
- SIMPLE file delete: the original files are simply deleted; if someone uses a specialized software (like forensic software), the deleted files could be fully recovered;
- SECURE file delete: before deleting them, the original files are overwritten with random sequences of bytes several times, then they are effectively deleted.
This technique is named “wiping” because it tries to wipe any track of a file from its original location, in order to make harder, if not impossible, to recover the contents of a file by specialized software. However this technique has some technical limitation when applied to storage media that uses flash memory chips like solid state disk (SSD), USB sticks o mobile devices memories (like internal storage of smartphones and mini/microSD memory card). This kind of storage faces a limited number of read/write cycles: the wear leveling techniques employed in these media, doesn’t treat storage as a common hard disk (HDD) would do, then deleting a file won’t leave some free space that could be reused but the file still stays there, marked for a future overwriting. If you try to update a file on such media, the newer version gets written in a new location and the older one lays where it is, just waiting to be overwritten.
This technical note makes the “SECURE file delete” option completely ineffective and, for this reasons, it is not available in CZIP X versions for Android and Windows 10 Mobile.
In CZIP X versions for Windows 10, Linux and macOS, “SECURE file delete” option is available but, is selected by user, the application decides wether to use it or not, depending from the location where original files are (e.g.: if files are in a HDD or not).
We suggest to use full disk encryption system on your mobile devices and with SDD media (like BitLocker for Windows or native filesystem encryption available in Android and Windows 10 Mobile).