What is Metadata?
Metadata is "data about data." While encryption protects the content of your communications, metadata reveals the context: who you talked to, when, for how long, and from where.
Former NSA Director Michael Hayden
"We kill people based on metadata."
Types of Metadata
Communication
Who, when, duration, frequency
High RiskLocation
GPS, cell towers, IP addresses
High RiskFile/Photo
EXIF data, creation date, device
Medium RiskBrowsing
Sites visited, time spent, patterns
High RiskHeaders, recipients, timestamps
Medium RiskDevice
Model, OS, unique identifiers
Medium RiskWhat Metadata Reveals
metadata-analysis
# Phone call metadata example
Called: Oncologist office → Health concerns
Called: Divorce lawyer → Relationship issues
Called: Suicide hotline → Mental health crisis
Called: Gun store + Called: Target → Potential threat
# Pattern analysis
2AM calls to same number → Affair
Regular calls before travel → Planning
Journalist + Whistleblower calls → Source
Protection Strategies
Communication Metadata
- Use Signal (minimal metadata collection)
- Use Tor for anonymous communication
- Avoid phone calls for sensitive matters
- Use burner phones/SIMs when needed
Location Metadata
- Disable location services when not needed
- Use VPN or Tor to hide IP location
- Leave phone at home for sensitive activities
- Disable WiFi/Bluetooth scanning
File Metadata
- Strip EXIF data from photos before sharing
- Use tools like ExifTool or mat2
- Take screenshots instead of sharing originals
- Use Tails (strips metadata automatically)
strip-metadata
# View image metadata
$
exiftool photo.jpg
# Strip all metadata
$
exiftool -all= photo.jpg
# Using mat2 (Metadata Anonymisation Toolkit)
$
mat2 --inplace document.pdf
Limitations
Complete metadata protection is extremely difficult:
Timing Analysis
When you're active online reveals patterns
Traffic Analysis
Size and frequency of encrypted traffic reveals information
Correlation
Multiple data points can be combined to identify you
Key Insight: Metadata protection requires changing behavior, not just tools. The best encryption is useless if your patterns are predictable.