---
title: "Links, overwrites and licences · DuplicateDuster"
description: "Symlinks never followed, a three-pass overwrite, hard-linking that cannot lose a file, and licensing without phoning home."
url: "https://royalsoftworks.com/products/duplicate-duster/security/safeguards/"
source: "https://royalsoftworks.com"
format: "markdown"
note: "Markdown rendering of the HTML page at `url`. Same content, same canonical URL."
---

Security & privacy · 2 of 3

# Links, overwrites and licences.

Symlinks never followed, a three-pass overwrite, hard-linking that cannot lose a file, and licensing without phoning home.

## Symlinks never followed

Symbolic links are neither traversed nor reported. Resolving one and deleting what it points at is exactly the failure mode a deduplication tool must not have.

## Three-pass secure overwrite

The optional secure erase overwrites a file's data three times (0xFF, then 0x00, then random bytes), renames it repeatedly so the original name doesn't survive in the directory entry, zeroes the timestamps, and then unlinks it. Each pass is flushed to disk rather than left sitting in the page cache. On Linux it hands off to shred where available.

## Hard-linking that can't lose a file

In hard-link mode the copy is renamed aside before the link is created, never unlinked first. If the link can't be made — different volume, unsupported filesystem, permissions — the rename is undone and you still have your file. Both paths are checked for the same volume up front.

## Licensing without a phone-home habit

Activation validates a key once and caches the result; if the server is unreachable later the cached tier is kept rather than downgrading a paying user. Air-gapped machines activate from a signed licence file bound to that device, with no network involved.

[Previous What is actually in place.](https://royalsoftworks.com/products/duplicate-duster/security/in-place/) [Next What we are not claiming.](https://royalsoftworks.com/products/duplicate-duster/security/not-claiming/)

[All of DuplicateDuster security](https://royalsoftworks.com/products/duplicate-duster/security/)

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