"We don't read your emails." "We don't see the content of your photos." These promises are often true... for content. But metadata is another story. This invisible information associated with every file or communication can reveal far more than the content itself.
What Are Metadata?
Metadata is data about data. It describes a file without constituting the main content.
A photo includes:
- Content: what you see in the image
- Metadata: date and time of capture, camera model, GPS coordinates of the location, orientation, exposure settings...
An email includes:
- Content: the message text
- Metadata: sender, recipient, date, time, sender's IP address, servers traversed, message subject...
A Word document includes:
- Content: the text
- Metadata: author, creation date, modification date, computer username, revision history...
What Metadata Reveals
EXIF Photo Data
EXIF (Exchangeable Image File Format) data embedded in every photo can include:
GPS Location: if your phone's GPS was active when taking the photo, the exact position is recorded in the photo. Publishing a photo "from home" can reveal your home address.
Exact date and time: allows reconstructing your movements if you publish regularly.
Camera model: can help identify the source of a photo in legal or journalistic contexts.
Document Metadata
A shared Word or PDF document may contain:
- The author's full name (taken from the Microsoft or Adobe account)
- The computer name used to create the document
- The revision history (previous versions, deleted text)
- The original creation date (which may differ from the displayed date)
- Hidden comments or revision notes
Investigative journalists regularly use document metadata to identify sources or verify dates.
Communication Metadata
Emails: without reading the content, metadata reveals who you communicate with, how often, from what IP address (thus which country, often which city).
Signal: even Signal, renowned for privacy, retains legally required minimum metadata. In practice, Signal minimizes this metadata to the maximum (only account creation date and last connection date).
Phone calls: carriers retain call logs (who calls whom, when, how long) without listening to conversations.
Concrete Risks
Doxxing and Harassment
Photos published online with GPS coordinates can allow malicious individuals to locate your home or workplace.
Surveillance and Profiling
Communication metadata allows reconstructing your social network and habits without ever accessing the content of your messages.
Involuntary Leaks in Professional Documents
An internally shared document that leaks externally can reveal information about your organization through its metadata (authors, dates, internal structure).
How to Clean Metadata
Photos
On iPhone: since iOS 13, you can remove location information when sharing. Go to Photos > Select photo > Share > Options > Disable "Location."
On Android: most gallery apps offer a similar option.
ExifTool software: free, open source command-line tool for reading and removing all EXIF metadata from your photos.
ExifCleaner software: graphical interface for ExifTool, more accessible for non-technical users.
Documents
Microsoft Word: File > Info > Check for Issues > Inspect Document. Remove personal information.
LibreOffice: Tools > Options > LibreOffice > User Data (to limit stored data).
PDFs: use Acrobat Pro or an online tool to remove metadata before sharing.
What EchoPass Does with Metadata
EchoPass adopts a metadata minimization policy. We only collect information strictly necessary for the service to function. Your message content is encrypted with XChaCha20-Poly1305 before reaching our servers. Even the metadata we retain doesn't allow inferring your message content.
Our privacy policy precisely details what metadata we retain and why.