Contents
Secure deletion & storage media
Normal deletion only removes the reference to a file — the content stays on the medium and can be restored with special tools (which is exactly what the reconstructor in chapter 11 does). With secure deletion, SynQaiPro overwrites the file several times beforehand, so that the original content is practically impossible to reconstruct.
13.1 Where you switch secure deletion on
There is no separate “secure deletion” window — the function is built into the places where deletion happens:
- via the delete dialogue from the context menu of the file trees (🗑 Delete, chapter 6);
- via the secure-deletion bar that appears in the file organiser (chapter 9), the duplicate finder (chapter 8) and the comparison list (in red delete mode).
13.2 The three methods
In both cases you choose how thoroughly the overwriting is done:
| Method | Passes | Pattern |
|---|---|---|
| ⚡ Fast (1×) | 1 | one pass with random data |
| 🛡 Medium (3× DoD) | 3 | DoD 5220.22-M (zero · one · random) |
| 🔒 Strong (7× DoD) | 7 | DoD 5220.22-M (ECE) |
Every file is overwritten in place (bypassing the write cache, with a flush to the medium after each pass), then truncated to length 0, renamed to a random name and finally deleted — so its size and name disappear too. During secure deletion you see byte-accurate progress; the estimated additional time appears on the right of the bar (“⏱ Additional time for secure deletion: ~…”).
13.3 The delete dialogue
If you delete an entry in the file tree, the Delete dialogue appears. Its introductory text states what will happen (“… will be deleted. This action is irreversible.”). You choose between Simple deletion and Secure deletion (overwrite) together with the method (fast — 1 pass · medium — 3 passes · strong — 7 passes).
Directly beneath the introductory text, the medium being deleted from is highlighted — the drive letter and, if assigned, the volume name: “Drive: B:\ (Backup)”. If the entry is on a network share, its path appears instead (“Network share: \\server\share”). The line also applies to a multiple selection; if the marked entries happen to be spread across several media, it stays empty rather than singling one out.
13.4 Whole drives and free space
If you open the delete dialogue on a drive root, it offers additional options behind a red warning (“Caution: this affects an ENTIRE DRIVE and is irreversible.”). Which of them appear depends on the medium — SynQaiPro shows only what actually helps on that type of drive:
| Option | Appears on | Effect |
|---|---|---|
| Simple delete | all | removes the contents without overwriting them |
| Wipe drive — securely remove all contents | hard disks | overwrites and removes all contents of the drive |
| Securely overwrite free areas | hard disks | leaves existing files untouched and overwrites only the free space — this makes remnants of already deleted files unreadable |
| 🔑 Securely erase SSD — the optimal method | SSDs | deletes all data and overwrites the free space once — preselected |
On an SSD the two overwriting options therefore do not appear at all. That is deliberate: there is exactly one right method there, and a choice between two “secure” routes would be a decision that helps nobody.
How long overwriting free areas takes
The operation fills the entire free area once — and again for every pass. The duration therefore depends on three things: how much is free, how many passes the chosen method uses (1×/3×/7×, see 13.2) and how fast the medium writes. As a rule of thumb: free space × passes ÷ write speed.
| 500 GB free on … | ⚡ Fast (1×) | 🛡 Medium (3×) | 🔒 Strong (7×) |
|---|---|---|---|
| an external disk over USB (~33 MB/s) | a good 4 hours | about 13 hours | over 30 hours |
| an internal disk (~120 MB/s) | a good hour | about 3.5 hours | about 8 hours |
While it runs, the banner above the progress bar shows “🧹 Overwriting free space…” and next to it the current “Pass 1/3”; the bar accounts for all passes together. Cancelling is possible at any time — whatever has been overwritten stays overwritten, the rest stays as it was. At the end the log notes “🧹 Free space overwritten: E:\ (3 passes)”.
On an SSD: the crypto method
On an SSD, overwriting repeatedly does not achieve its purpose. The controller spreads every write across free cells — the old data may well still be there afterwards, just elsewhere. Seven passes are therefore no safer than one, they merely cost seven times the time and write cycles. For detected SSDs the dialogue thus offers 🔑 Securely erase SSD — the optimal method as the only secure route and preselects it. Three steps run:
- If a SynQaiCrypt vault lies on the drive, its key is destroyed first. Its contents are instantly unreadable — without a single write.
- All data is deleted. On flash storage this is not a side step but the most effective one: the file system reports the blocks as free via TRIM, and the medium actually erases them internally.
- The free area is overwritten once with cryptographic random data. Every addressable location on the medium has then been overwritten.
The method needs no BitLocker, no administrator rights and no vendor tool and is available on every detected SSD — a vault is not a prerequisite, it merely speeds things up.
How long it takes
The third step decides: the free area is written full once. On a 500 GB SSD that is about half an hour over USB and roughly ten minutes internally. The first two steps hardly matter beside it — deletion depends on the number of files (seconds to a few minutes), and an existing vault key is destroyed in about a second.
| 500 GB SSD | 🔑 Crypto method (1×) | Overwriting 7× |
|---|---|---|
| over USB (~33 MB/s) | a good 4 hours | over 30 hours |
| internal (~500 MB/s) | about 20 minutes | a good 2 hours |
If a vault lies on the drive, the picture changes fundamentally: the data is then unreadable after about a second — as soon as the key is gone. Everything after that is mere tidying up and can be cancelled at any time without diminishing security.
The medium line from section 13.3 appears here too — with the letter and the name. For an operation of this magnitude it is the most important check before the click.
13.5 Keeping an eye on the media
Two further helpers work around the storage media:
- A SMART early warning: if the source drive reports an imminent failure, the file reconstructor shows a red warning banner (“⚠ Medium reports imminent failure”) and advises creating a sector image first (chapter 11).
- BitLocker auto-unlock: a small window at Windows start-up that unlocks remembered drives via Windows Hello — set up in the encryption module (chapter 14).