Your Phone Is a Surveillance Device You Carry Voluntarily

A modern smartphone contains your entire digital life — communications, credentials, location history, biometric data, financial accounts, and social graph. In high-risk environments, that device becomes the single most valuable intelligence target on your person.

Whether you’re a journalist entering a country with aggressive surveillance, an activist attending a protest, a security researcher at a border crossing, or a business traveler with sensitive data — your phone needs hardening before you step into the zone.

Threat Model First

Before configuring anything, define your threat model:

Questions to answer:
  1. Who is the adversary? (state, criminal, corporate)
  2. What capabilities do they have?
     - Physical device access (border search, arrest)
     - Network surveillance (IMSI catchers, deep packet inspection)
     - Remote exploitation (zero-days, spyware)
  3. What data are you protecting?
     - Sources and contacts
     - Communications content
     - Location history
     - Credentials and access
  4. What are the consequences of compromise?
     - Inconvenience → imprisonment → physical danger

Your security measures should be proportional to your threat level. A tourist in a mildly authoritarian country needs different protections than a war correspondent in an active conflict zone.

Pre-Departure Preparation

Option 1: Travel with a Burner Device

The safest approach — bring a clean device with minimal data:

# Setup checklist for a burner phone:
  □ Factory-fresh device (or freshly wiped)
  □ New SIM card (purchased with cash if possible)
  □ Fresh email account for this trip only
  □ No personal accounts logged in
  □ Only essential apps installed
  □ No photos, contacts, or files from primary device
  □ Strong alphanumeric passcode (not biometric)

Option 2: Harden Your Primary Device

If a burner isn’t feasible:

# Before departure:
  □ Update OS and all apps (patch known vulnerabilities)
  □ Full encrypted backup to secure location
  □ Remove sensitive apps (banking, corporate, dating)
  □ Sign out of non-essential accounts
  □ Delete sensitive messages and photos
  □ Disable biometric unlock (enable strong passcode only)
  □ Enable remote wipe capability
  □ Document device IMEI for remote wipe if seized

Why Disable Biometrics?

Legal reality in many jurisdictions:
  - You can be compelled to provide your fingerprint or face
  - You generally cannot be compelled to reveal a passcode
    (varies by jurisdiction, but the principle holds more often)

Technical reality:
  - Unconscious/incapacitated? Face/finger still works
  - Detained and hands forced onto sensor? Unlocked.
  - 6+ digit alphanumeric passcode? They need your cooperation.

On iPhone:  Settings → Face ID → disable
On Android: Settings → Security → Screen Lock → PIN/Password only

Emergency lockdown:

  • iPhone: Press side button + volume 5 times → Emergency SOS (disables biometrics)
  • Android: Press power button → select Lockdown mode (if enabled)

Communication Security

Encrypted Messaging

Signal (recommended):
  ✓ End-to-end encrypted by default
  ✓ Disappearing messages (set to 1 hour in high-risk zones)
  ✓ Screen security (prevents screenshots)
  ✓ Registration lock (prevents SIM swap account takeover)
  ✓ Sealed sender (hides metadata from Signal servers)

Configuration:
  Signal → Settings → Privacy:
    □ Enable "Screen Lock"
    □ Enable "Screen Security"
    □ Set "Disappearing Messages" → custom timer
    □ Enable "Registration Lock"
    □ Disable "Link Previews"
    □ Disable "Typing Indicators"

Network Protection

# Always-on VPN
# iOS: Settings → VPN → Connect On Demand → Enable
# Android: Settings → Network → VPN → Always-on VPN

# Recommended VPN providers for hostile environments:
# - Mullvad (accepts cash, no account info required)
# - ProtonVPN (Swiss jurisdiction, open source)
# - IVPN (Gibraltar, strong no-log policy)

# For extreme scenarios: Tor
# Install Orbot (Android) or use Onion Browser (iOS)

Device Hardening

iOS Lockdown Mode

Apple’s Lockdown Mode is specifically designed for high-risk targets:

Settings → Privacy & Security → Lockdown Mode → Turn On

What it does:
  ✓ Blocks most message attachment types
  ✓ Disables link previews
  ✓ Blocks incoming FaceTime from unknown callers
  ✓ Blocks wired connections when locked
  ✓ Removes shared albums
  ✓ Blocks MDM profile installation
  ✓ Reduces attack surface for zero-click exploits

Who should use it:
  Journalists, activists, dissidents, security researchers
  in environments where state-level spyware is a concern

Android Hardening

Essential settings:
  □ Settings → Security → Encryption → Verify device is encrypted
  □ Settings → Developer Options → Disable USB debugging
  □ Settings → Security → Device admin apps → Remove unnecessary
  □ Settings → Apps → Disable/uninstall bloatware
  □ Settings → Location → Disable when not needed
  □ Settings → Connected devices → Disable NFC, Bluetooth when idle

Advanced (GrapheneOS recommended for high-risk users):
  # GrapheneOS — hardened Android for Pixel devices
  # Includes: verified boot, hardened memory allocator,
  #           network/sensor permissions, per-app exploit mitigations
  # https://grapheneos.org

For Both Platforms

# Minimize installed apps
# Each app is an attack surface. Audit ruthlessly.

# Check app permissions
# iOS: Settings → Privacy & Security → [each category]
# Android: Settings → Apps → [app] → Permissions

# Disable Wi-Fi auto-join
# Your phone broadcasts every network it's ever connected to
# Attackers use this for tracking and evil twin attacks

# Disable Bluetooth when not in use
# BlueBorne and similar attacks target Bluetooth stack

# Enable airplane mode when device should be silent
# Prevents cellular, Wi-Fi, and Bluetooth radio emissions

Counter-Surveillance

IMSI Catcher Detection

IMSI catchers (Stingrays) are fake cell towers that intercept communications:

Signs of IMSI catcher presence:
  - Unexpected 2G/3G downgrade (forced from 4G/5G)
  - Rapid battery drain
  - Unusual network behavior near government buildings
  - Multiple "tower changes" in a static location

Countermeasures:
  Android: Settings → Network → Preferred network type → 5G/LTE only
           (blocks 2G downgrade attacks)
  iOS: Settings → Cellular → Cellular Data Options → Voice & Data → 5G/LTE

  For detection:
  - Android IMSI-Catcher Detector (AIMSICD) — open source
  - SnoopSnitch (requires rooted device, Qualcomm chipset)
  - Rayhunter — IMSI catcher detection (by EFF)

Location Discipline

Your phone leaks location through multiple channels:
  1. GPS (direct satellite positioning)
  2. Cell tower triangulation
  3. Wi-Fi positioning (known access point locations)
  4. Bluetooth beacons
  5. Photos with EXIF GPS data

Countermeasures:
  □ Disable location services when not actively navigating
  □ Use offline maps (OsmAnd, downloaded before travel)
  □ Strip EXIF data from photos before sharing
  □ Leave phone behind for sensitive meetings (or Faraday bag)
  □ Review and delete location history regularly

Faraday Bags

When you need absolute radio silence:

What a Faraday bag does:
  - Blocks all RF emissions (cellular, Wi-Fi, Bluetooth, GPS, NFC)
  - Prevents remote tracking and activation
  - Phone cannot be reached or locate itself

When to use:
  - Transiting through hostile checkpoints
  - Meetings where phone presence is a liability
  - When you suspect your device is compromised but can't wipe yet
  - Preventing remote wipe before forensic preservation

Note: Phone must be in bag BEFORE entering sensitive area.
      Taking phone out briefly in the area defeats the purpose.

Border Crossing Protocol

Border agents in many countries have broad authority to search electronic devices:

Pre-crossing checklist:
  □ Back up device to encrypted cloud storage
  □ Sign out of all accounts
  □ Delete sensitive apps and data
  □ Clear browser history and caches
  □ Power off device (FDE protection activates)
  □ Consider: ship primary device ahead via secure courier

If device is seized:
  □ Note the agent's name/badge number
  □ Note time and circumstances
  □ Do not provide passwords voluntarily (know your legal rights)
  □ Contact legal counsel immediately after
  □ Assume device is compromised if returned
  □ Do NOT use the device without forensic examination

After crossing:
  □ Re-install apps from fresh downloads
  □ Re-authenticate accounts from a clean network
  □ Change passwords for any accounts that were logged in
  □ Monitor accounts for unauthorized access

Emergency Procedures

If you believe your device is actively compromised:
  1. Enable airplane mode immediately
  2. Do not power off (preserves volatile forensic evidence)
  3. Place in Faraday bag if available
  4. Switch to backup communication method
  5. Contact security team or trusted technical support
  6. Do not attempt to "clean" the device yourself

If you need to destroy data immediately:
  iOS:  Settings → General → Transfer or Reset → Erase All Content
  Android: Settings → System → Reset → Factory data reset
  
  Note: Remote wipe via Find My iPhone / Find My Device
        requires network connectivity

The Human Factor

No amount of technical hardening defeats poor operational security:

  • Don’t discuss sensitive topics near any electronic device
  • Assume hotel rooms and meeting spaces are monitored
  • Vary your routines and routes
  • Trust your instincts — if something feels wrong, act on it
  • Have a check-in protocol with someone outside the risk zone
  • Know the emergency contacts: embassy, legal counsel, press freedom organizations

Your phone is a tool. In high-risk environments, it can become a liability. Understand the trade-offs, harden what you can, and always have a plan for when technology fails you.