Why use secure deletion?

سیستم‌عامل‌ها هنگام پاک کردن فایل‌ها محتوای آن‌ها را کامل از بین نمی‌برند، حتی پس از خالی کردن سطل آشغال رایانه یا پاک کردن فایل از راه‌های دیگر مانند استفاده از خط فرمان.

Instead, they simply remove the file's entry from the file system directory, because this requires less work and is therefore faster. The contents of the file—the actual data—remain on the storage medium. The data will remain there until the operating system reuses the space for new data.

به همین ترتیب فرمت کردن دوباره، پارتیشن‌بندی یا گرفتن تصویر دوباره از رایانه همیشه تضمین‌کنندهٔ پاک کردن تمام نقاط دیسک نیست، با این که با انجام دادن هر کدام از آن‌ها از نظر نرم‌افزار این طور به نظر می‌آید که دیسک خالی است؛ یا در مورد گرفتن ایمج دوباره، دیسک به جز فایل‌های موجود در تصویر خالی است.

Finally, even when the storage medium is overwritten, physical properties of the medium might make it possible to recover the previous contents. In most cases however, this recovery is not possible by just reading from the storage device in the usual way, but requires using laboratory techniques such as disassembling the device and directly accessing/reading from its components.

To learn more, see the Wikipedia article on data erasure.

Warning about USB sticks and solid-state disks

The only way to securely delete any data, even a single file, from a USB stick or an SSD (Solid-State Disk) is to securely erase the entire device.

For more details read the corresponding section of the Wikipedia article on data erasure.

Securely delete files

1. Open the Files browser.

2. به پوشه‌ای بروید که فایل‌هایی که می‌خواهید پاک کنید در آن هستند.

3. فایل‌ها را که می‌خواهید پاک کنید با موش‌واره انتخاب کنید.

4. Right-click (on Mac, click with two fingers) on the files and choose Wipe.

5. تأیید کنید.

6. The deletion will start. It can last from a few seconds to several minutes, according to the size of the files. Be patient…

Securely clean available disk space

همچنین می‌توان برای پاک کردن محتویات تمام فایل‌ها که پیش از این حذف شده بودند اما به طور امن پاک نشده بودند، به طور امن تمام فضای خالی دیسک را پاک کرد.

The disk or the folder can contain other files. Those files will not be deleted during the operation.

1. Open the Files browser.

2. دیسکی که می‌خواهید پاک کنید را از سمت راست انتخاب کنید تا به روت دیسک برسید.

3. Click on the button in the right corner of the title bar and choose Show Hidden Files.

4. If you want to empty the trash, delete the .Trash-1000 folder or similar.

5. Right-click (on Mac, click with two fingers) in empty space in the right pane and choose Wipe available diskspace.

6. تأیید کنید.

7. The cleaning starts. It can last from a few minutes to a few hours, according to the size of the available diskspace. Be patient…

   Note that a file with a name similar to tmp.7JwHAyBvA9 is created in the folder. It is made as big as possible to use all the available diskspace and then securely deleted.

Securely erasing an entire device

1. Open the Disks utility.

   All the current storage devices are listed in the left pane.

2. Plug in the USB stick or SSD that you want to securely delete.

3. A new device appears in the list of storage devices. Click on it:

   

4. Check that the description of the device on the right side of the screen corresponds to your device: its brand, its size, etc.

5. Click on the button in the titlebar and choose Format Disk… to erase all the existing partitions on the device.

6. In the Format Disk dialog:

   • Choose to Overwrite existing data with zeroes in the Erase drop-down list.

   • Choose Compatible with all systems and devices (MBR/DOS) in the Partitioning drop-down list.

7. Click Format….

8. In the confirmation dialog, make sure that the device is correct. Click Format to confirm.