Question 1

What metadata does a file contain, and what can it reveal?

Accepted Answer

**Metadata** is data about the file rather than its visible content. Almost every file carries some, and it frequently reveals considerably more than people intend to share.

**Photographs — EXIF data:**

**GPS coordinates**, if location services were enabled. This is the most consequential field, and it has repeatedly revealed home addresses from photos posted online.

**Date and time** taken, to the second.

**Camera make, model and serial number**, which can link photographs to a specific device.

**Lens, exposure settings and whether the flash fired.**

**Thumbnail**, which on some older software was not updated when the image was edited — meaning a cropped photo could contain a thumbnail of the original.

**Documents:**

**Author name** and the organisation from the software licence.

**Revision history and tracked changes**, sometimes including deleted text still present in the file.

**Comments** not visible in the default view.

**Created, modified and total editing time.**

**File paths**, which can expose usernames and internal directory structures.

**PDFs** retain producing software and often the source document's metadata. **Redaction failures** are a recurring embarrassment — black rectangles drawn over text leave the text selectable underneath, and this has exposed confidential information in court filings and government releases repeatedly. Proper redaction removes the content, not just the appearance.

**Audio and video** carry device, software, timestamps and sometimes location.

**Office and cloud documents** may retain collaborator names and version history.

**How to check and remove it:**

**Windows** — file Properties, Details, "Remove Properties and Personal Information".

**macOS** — Preview and various tools, or the `exiftool` utility across platforms.

**Dedicated metadata scrubbers** exist and are worth using before publishing.

**Note that many social platforms strip EXIF on upload**, which helps — but messaging apps and email attachments frequently do not.

Question 2

What is content provenance, and what is C2PA?

Accepted Answer

A way of recording where a piece of media came from and what was done to it, cryptographically attached to the file — an approach to the synthetic media problem that works in the opposite direction

Question 3

What is the difference between a file format and a file extension?

Accepted Answer

A file format is the actual structure of the data inside the file. A file extension is the few characters after the dot in the filename — a label, and nothing more. The crucial point is that the

Question 4

What is a subject access request, and what must an organisation provide?

Accepted Answer

A right of access under data protection law allowing anyone to ask an organisation what personal data it holds about them, and to receive a copy — and the scope is wider than most organisations

Question 5

Why do old files become unreadable, and what is digital preservation?

Accepted Answer

Because a file is only meaningful to software that understands its format, and both the software and the medium it sits on decay — on timescales far shorter than people assume. The three separate

Question 6

Why do apps ask for so many permissions?

Accepted Answer

For a mixture of genuine functional need, defensive over-requesting, and data collection — and the three are difficult to distinguish from the request alone. Legitimate reasons: The feature requires

Question 7

What is the difference between anonymisation and pseudonymisation?

Accepted Answer

Whether the data can still be linked back to a person. Anonymised data cannot, and falls outside data protection law entirely. Pseudonymised data can, with additional information, and remains fully

Related Questions