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Secure delete on flash based storageFlash units (as solid state disks SSD or USB keys) usually re-allocates sectors for writing transparently for the software, in order to reduce unit’s wear since flash units have a shorter lifespan in terms of writes; this doesn’t allow to efficiently wipe and physically overwrite original content, reducing the efficiency of file shredding.In this case only erasing the whole disk (with one or more random data passage on all the free space) would be effective to securely erase remnants of data, but this can be very time consuming and, for flash based or hybrid drives, it will lead to fast wear and reduced lifespan of devices. Secure delete on cloud and remote storageData stored on remote servers (as in cloud services, even freeware ones) may be subject to periodic backup unknowingly to users, so please consider that copy of the data before erasure may exists on servers, out of the reach of users, if such services are employed, unless differently specified in terms of service.Moreover, as terms of services are often subject to variations, and limitations in user's rights depending on the laws applying to the provider of the services (such as, possibly, do any effort in providing access to user's data under some circumstances), it is highly recommended encrypting data on user's end before upload to any external machine, even when encryption (or user data erasure) is offered as service by the remote storage / cloud service provider. "Quick delete" is provided as an alternative to secure deletion by PeaZip file manager, this action deletes files and folders without moving data to the recycle bin, which is faster and increases security against forgetting of recycled data. Like secure deletion, fast deletion does not allows to recover data from the system's recycle bin, and in this sense it provides a simple way to permanently erase data, but this procedure is not intended for securely sanitizing data: as no data overwriting stage is involved in the process, it is feasible to recover data destroyed with fast delete using appropriate undelete utilities. In this way leftover remnants of data previously saved to disk (deleted files, reallocated sectors, ...) are wiped and replaced by random data generated by the disk eraser program, making analysys of free space useless. This level of security is not matched by formatting the volume, as quick format routines does not overwrite existing data, which can be recovered with specific utilities, and even more through format utilities does not implement a multi-pass overwriting of free space with random data, making previous state of the disk recoverable with suitable hardware scanning equipment. Zero delete files and free space is also available, the function overwrites data with all zeroes before deletion. It is recommended to be performed before saving disk images either of physical machines (for backup and disaster recovery) and for virtual machines' disk images, as more uniform (zeroed) data is much more easily compressible - learn more optimizing virtual machines and disk images backup - but it is not recommended when it is needed to sercurely erase disk content so it becomes unrecoverable by specialized data recovery (undelete) software. Windows system, from Windows 7 onward, zeroes bytes on drives when performing full format, while quick format simply de-reference the files without overwriting leftover data traces. Read more about secure data deletion: data erasure  , and data
recovery Wikipedia
entries, disk sanitization software examples: OS X
Disk Utility, and
Microsoft cipher
/w command.Synopsis: How to use
PeaZip as freeware Open Source cross platform data deletion utility for
Windows
and Linux. Secure deletion of files and folders (file wipe). Secure
deletion of free disk space to sanitize media supports. PeaZip > FAQ >
Free, Open Source secure delete utility |
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