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📱 Mobile Privacy & Security Configuration Guide

Last Updated: December 2025
Compatible Systems: iOS 18+, Android 14+, HarmonyOS 5, MagicOS 8, HyperOS 2
Setup Time: 5-10 minutes
No Jailbreak/Root Required


📋 Table of Contents


I. Configuration Goals

This guide uses native system settings (no third-party tools required) to achieve three main objectives:

🔒 Goal 1: Set Strong Lock Screen

  • Use PIN (≥6 digits) as the first line of defense
  • Avoid weak passwords like birthdays or phone numbers

🚫 Goal 2: Disable Sensitive Data Collection

  • Disable system analytics, telemetry, and crash log uploads
  • Turn off advertising identifiers
  • Stop personalized ad tracking

🔐 Goal 3: Encrypt Network Functions

  • Use encrypted DNS (DoH) to prevent hijacking and tracking
  • Keep keyboard clipboard data local (no cloud sync)
  • Use open-source/encrypted communication tools

II. iOS Configuration Guide

Compatible Devices

iPhone 12 and above (iOS 17+)

Configuration Checklist

# Item Path Steps Verification
1 Set PIN Lock Settings → Face ID & Passcode → Change Passcode 1. Tap "Passcode Options"
2. Choose "Custom Numeric Code"
3. Enter ≥6 digits (avoid sequential numbers)
Lock screen shows only numeric keypad
2 Disable Analytics Settings → Privacy & Security → Analytics & Improvements Turn off all options:
- Share iPhone Analytics
- Share iCloud Analytics
- Improve Siri & Dictation
- Share Routing & Network Analytics
Enter "Analytics Data" - no new logs
3 Disable Ad Tracking Settings → Privacy & Security → Tracking Turn off "Allow Apps to Request to Track" Toggle grayed out, apps no longer show tracking prompts
4 Configure Encrypted DNS Settings → General → VPN & Device Management Option 1: Profile (Recommended)
1. Visit in Safari: https://adguard-dns.io/kb/en/ios/solving-problems/configuration-profile/
2. Download "Default" profile
3. Install in Settings

Option 2: 18bit DNS (China-based, Ad Blocking)
1. Visit in Safari: https://go.18bit.cn/help-docs/help-docs-ios.html
2. Download 18bit DNS profile
3. Install in Settings
4. Auto-enabled after installation

Option 3: App Method
Download "AdGuard" or "DNSCloak"
AdGuard Verification:
Visit https://dns.adguard.com/info
Shows "DNS Protection: Yes"

18bit Verification:
Visit https://dtest.18bit.cn/
Red screen shows "18bit Blocked"
5 Localize Keyboard Settings → General → Keyboard → Keyboards 1. Keep only "Simplified Chinese - Pinyin" or use Gboard
2. If using Gboard, disable in settings:
- Cloud clipboard
- Input predictions
- Auto-learning
Copy sensitive content, paste after 5 min
Should show "Clipboard cleared"
6 Limit Location Tracking Settings → Privacy & Security → Location Services 1. Review app permissions individually
2. Change to "While Using" or "Never"
3. Disable "Precise Location"
Location icon no longer appears frequently in status bar
7 Disable Background Refresh Settings → General → Background App Refresh Disable background refresh for rarely-used apps Battery life improves

⚠️ iOS Special Notes

  • iCloud Backup: Backs up all app data. Disable iCloud backup for sensitive apps (banking, messaging)
  • Siri Suggestions: Settings → Siri & Search, disable "Learn from this App" for sensitive apps individually
  • Photo Privacy: Use "Hidden Album" and disable "Show Hidden Album" in Photos settings

III. Android Stock/AOSP Configuration Guide

Compatible Devices

Pixel, Stock Android, OnePlus OxygenOS, Nothing OS, etc.

Configuration Checklist

# Item Path Steps Verification
1 Set PIN Lock Settings → Security → Screen Lock → PIN Enter ≥6 digits (avoid sequential numbers) Lock screen shows only numeric keypad
2 Disable Telemetry Settings → Google → Usage & Diagnostics Turn off "Send usage and diagnostics data" Search "usage" in settings shows "Disabled"
3 Delete Ad ID Settings → Google → Ads Tap "Delete advertising ID"
(Android 12+)
or disable "Personalized ads"
Shows "Advertising ID deleted"
4 Configure Private DNS Settings → Network & Internet → Private DNS Select "Private DNS provider hostname"

Recommended Options:
- 18bit DNS (China, ad blocking): dns.18bit.cn
- AdGuard DNS (International, ad blocking): dns.adguard-dns.com
- Alibaba DNS (China, no blocking): dns.alidns.com
- Cloudflare (International, no blocking): 1dot1dot1dot1.cloudflare-dns.com
Status shows "Connected"

18bit Verification:
Visit https://dtest.18bit.cn/
Red screen shows success

AdGuard Verification:
Visit https://dns.adguard.com
Shows "DNS Protection: Yes"
5 Localize Keyboard Settings → System → Languages & Input → Gboard Enter Gboard settings:
- Disable "Clipboard cloud sync"
- Disable "Personal dictionary cloud sync"
- Disable "Share usage statistics"
Copy password, switch apps
Long press paste shows no history
6 Review Permissions Settings → Privacy → Permission Manager Check individually:
- Location (change to "Only while using")
- Camera/Microphone (disable unnecessary apps)
- Contacts (keep only necessary apps)
Permission icons no longer appear frequently in status bar
7 Limit Background Activity Settings → Apps → Special App Access → Unrestricted Data Usage Keep only necessary communication apps Data usage decreases

IV. Huawei/HarmonyOS Configuration Guide

Compatible Devices

Mate 60 series, Pura 70 series, Mate X5, nova series, etc. (HarmonyOS 4.0+)

Configuration Checklist

# Item Path Steps Verification
1 Set PIN Lock Settings → Biometrics & Password → Lock Screen Password Choose "PIN"
Enter ≥6 digits (disable "Simple password")
Lock screen shows only numeric keypad
2 Disable Experience Program Settings → Huawei Account → Privacy Center → Experience Improvement Turn off all options:
- User Experience Improvement Program
- Crash log upload
- Diagnostic data
Page shows "Disabled"
3 Delete Ad Identifier Settings → Huawei Account → Privacy Center → Ads & Privacy Tap "Delete advertising identifier" Shows "Advertising identifier disabled"
4 Disable System Telemetry Settings → System & Updates → User Experience Improvement Program Turn off "Join User Experience Improvement Program" Search "experience improvement" shows disabled
5 Configure Encrypted DNS Settings → More Connections → Encrypted DNS Select "Manual"

Recommended:
- dns.18bit.cn (China, ad blocking)
- dns.adguard-dns.com (International, ad blocking)
- dns.alidns.com (China, no blocking)
Status shows "Connected"

Verify: Visit https://dtest.18bit.cn/
Red screen shows success
6 App Lock + Background Blur Phone Manager → Privacy Center → App Lock 1. Lock sensitive apps like WeChat, email
2. Enable "Background blur preview"
Recent tasks show blurred content
7 PrivateSpace (Optional) Settings → Privacy → PrivateSpace Create independent fingerprint/password File Manager shows "PrivateSpace" entry at bottom
8 Pure Mode Settings → System & Updates → Pure Mode Keep enabled (default) Can only install apps from AppGallery and official channels

🔍 Huawei Quick Checklist

Use Settings search bar, search these keywords to ensure all are disabled:

  • ✅ "Experience improvement" → All toggles off
  • ✅ "Ads" → Advertising identifier deleted
  • ✅ "Diagnostic" → All diagnostic toggles off
  • ✅ "Cloud" → Check if sensitive data cloud sync is disabled

V. Honor/MagicOS Configuration Guide

Compatible Devices

Magic V3/V5, Magic6 series, Magic7 series, etc. (MagicOS 8.0+)

Configuration Checklist

# Item Path Steps Verification
1 Set PIN Lock Settings → Biometrics & Password → Lock Screen Password Choose "PIN"
Enter ≥6 digits (disable "Simple password")
Lock screen shows only numeric keypad
2 Disable Experience Program Settings → Honor Account → Privacy Center → Experience Improvement Turn off "Join Experience Improvement Program" Page shows "Disabled"
3 Delete Ad ID Settings → Honor Account → Privacy Center → Ads Tap "Delete advertising identifier" Shows "Advertising ID disabled"
4 Disable Remote Diagnostics Settings → System & Updates → Honor Remote Diagnostics Turn off "Allow remote log collection" Search "remote diagnostics" shows disabled
5 Configure Encrypted DNS Settings → More Connections → Encrypted DNS Select "Manual"

Recommended:
- dns.18bit.cn (China, ad blocking)
- dns.adguard-dns.com (International, ad blocking)
- dns.alidns.com (China, no blocking)
Status shows "Connected"

Verify: Visit https://dtest.18bit.cn/
Red screen shows success
6 App Lock Phone Manager → App Lock 1. Lock sensitive apps
2. Enable "Background blur"
Recent tasks show blurred content
7 On-Device AI (Magic V3/V5) Settings → Privacy → On-Device AI Choose "Local processing only"
Turn off "Cloud enhancement"
Knowledge base page shows "Pure on-device mode"

🔍 Honor Quick Checklist

Settings search bar, search sequentially:

  • ✅ "Experience improvement" → Disabled
  • ✅ "Ads" → ID deleted
  • ✅ "Remote diagnostics" → Disabled
  • ✅ "Cloud" → Check sync items

VI. Xiaomi/HyperOS Configuration Guide

Compatible Devices

Xiaomi 14 series, Redmi K70 series, Xiaomi 15 series, etc. (HyperOS 1.0+)

Configuration Checklist

# Item Path Steps Verification
1 Set PIN Lock Settings → Password & Security → Lock Screen Password Choose "PIN"
Enter ≥6 digits (disable "Simple password")
Lock screen shows only numeric keypad
2 Disable Experience Program Settings → Password & Security → System Security → User Experience Program Turn off "Join User Experience Program" Toggle grayed out
3 Delete Ad ID Settings → Password & Security → System Security → Ad Services Tap "Delete advertising ID" Shows "Advertising identifier disabled"
4 Disable Diagnostic Data Settings → Password & Security → System Security → Diagnostic Data Turn off "Send diagnostic data" Search "diagnostic data" shows disabled
5 Disable Personalized Ads Settings → Accounts & Sync → Mi Account → Privacy → Ad Preferences Turn off "Personalized ads" Page shows "Disabled"
6 Configure Private DNS Settings → Connection & Sharing → Private DNS Select "Manual"

Recommended:
- dns.18bit.cn (China, ad blocking)
- dns.adguard-dns.com (International, ad blocking)
- dns.alidns.com (China, no blocking)
Status shows "Connected"

Verify: Visit https://dtest.18bit.cn/
Red screen shows success
7 App Lock + Blur Snapshot Settings → App Settings → App Lock 1. Lock sensitive apps
2. Enable "Blur snapshot"
Recent tasks show blurred content
8 Disable MIUI Recommendations Settings → Search "recommendations" Turn off all "Content recommendations" options Negative screen no longer shows ads

🔍 Xiaomi Quick Checklist

Settings search bar, search sequentially:

  • ✅ "Experience program" → Disabled
  • ✅ "Ads" → ID deleted + personalized disabled
  • ✅ "Diagnostic data" → Disabled
  • ✅ "Recommendations" → All content recommendations disabled

VII. General Security Recommendations

🔄 Regular Maintenance (Quarterly)

  1. Recheck Toggle Status
    Search in Settings for these keywords to ensure they haven't been silently re-enabled:

    • "Experience improvement"
    • "Diagnostic data" / "usage"
    • "Advertising ID" / "ads"
  2. Clear Cache & Logs

    • Android: Settings → Storage → Cached Data → Clear
    • iOS: Settings → General → iPhone Storage → Clear "Other"
  3. Check Permission Changes
    Review new permission requests in "Permission Manager"

📶 Public Wi-Fi Protection

  1. Ensure Encrypted DNS is Enabled (Steps 4/5 above)
  2. Avoid Sensitive Operations: No banking, password changes, etc.
  3. Use HTTPS: Check URL prefix is https://
  4. Optional: Use VPN
    Recommended open-source solutions:
    • iOS: WireGuard, Shadowrocket
    • Android: WireGuard, v2rayNG
    • ⚠️ Avoid free Chinese accelerators (may log data)

🔍 DNS Tools Recommended

Tool Function Link
18bit DNS Test Check if 18bit DNS is active https://dtest.18bit.cn/
AdGuard DNS Test Check if AdGuard DNS is active https://dns.adguard.com/info
DNS Leak Test Check if DNS leaks real IP https://www.dnsleaktest.com/
18bit Service Status View 18bit DNS real-time status https://status.18bit.cn/

📱 Keyboard & Clipboard

Platform Recommended Solution Configuration
iOS System default / Gboard Gboard needs "Cloud clipboard" disabled
Android Gboard / System default Disable "Cloud sync" and "Statistics"
Chinese ROMs System default Avoid third-party input methods

Security Tips:

  • After copying passwords/codes, system auto-clears in 5 minutes
  • Don't use Sogou, Baidu, or other internet-connected third-party keyboards

🔒 App Security Recommendations

App Type Recommendation
Messaging (WeChat/QQ) Enable app lock + hide notification content
Financial (Banking/Payment) Enable app lock + disable cloud backup
Notes Use local notes (Apple Notes/Google Keep)
or E2E encrypted notes (Notion/Obsidian)
Email Disable auto-load images (prevent tracking pixels)
Browser Use Safari (iOS)/Chrome (Android)
Enable "Prevent cross-site tracking"

🛡️ System Updates

Platform Update Recommendation Notes
iOS Keep auto-update enabled Apple responds quickly to security issues, safe to upgrade
Android Stock Keep auto-update enabled Google pushes security patches first week of each month
Huawei/Honor/Xiaomi Only install "Security patches" Wait 1-2 weeks before major version updates to avoid issues

⚠️ Important: System security patches won't re-enable privacy toggles, safe to upgrade


VIII. Frequently Asked Questions

❓ Some Apps Don't Work After DNS Configuration?

Cause: DNS with ad blocking (18bit, AdGuard) blocks some ads and tracking domains. Some apps require ads to function.

Solutions:

  1. Temporary: Disable encrypted DNS, re-enable after using the app
  2. Permanent: Switch to non-blocking DNS
    • Alibaba DNS (China, no blocking): dns.alidns.com
    • Cloudflare (International, malware blocking only): 1dot1dot1dot1.cloudflare-dns.com

❓ 18bit DNS vs AdGuard DNS - Which to Choose?

Comparison 18bit DNS AdGuard DNS
Server Location 🇨🇳 China Mainland 🌍 Overseas (Singapore, USA, etc.)
China Speed ✅ Fast (latency <20ms) ⚠️ Average (latency 50-100ms)
Ad Blocking ✅ Optimized for Chinese ads ✅ Optimized for international ads
Privacy Policy 🔍 Check official website ✅ Open source, has audit reports
Stability ⚠️ Occasional attacks ✅ High
Use Case Chinese users daily use Privacy-focused or frequent international app users

Recommended Choice:

  • 🏠 China users priority: dns.18bit.cn (fast, blocks Chinese ads)
  • 🌏 Privacy priority/overseas apps: dns.adguard-dns.com (open source transparent)
  • ⚡ Stability priority (no ad blocking): dns.alidns.com (Alibaba Public DNS)

❓ Forgot PIN Password?

Platform Solution
iOS Need to restore device via iTunes/Finder (data will be lost)
If "Find My iPhone" is enabled, can remotely erase
Android After multiple wrong attempts, can unlock with Google account
or restore factory settings via Recovery (data loss)
Chinese ROMs Most can recover via brand account
or use "Forgot password" (need pre-bind)

💡 Suggestion: Use password manager (1Password/Bitwarden) to backup PIN

❓ Will I Still See Ads After Disabling Ad ID?

Yes, but ads won't be personalized.

  • Before: Apps push targeted ads based on browsing history, location, purchase records
  • After: Apps can only push generic ads (all users see same ads)

Key Difference: Protects privacy, doesn't completely remove ads (ad removal requires encrypted DNS)

❓ Should I Enable "Pure Mode" on Huawei/Honor/Xiaomi?

Mode Pros Cons Recommendation
Pure Mode Only install apps from official channels
Blocks malware
Can't install third-party APKs
(e.g., GitHub open-source apps)
✅ Regular users keep enabled
❌ Developers/geeks can disable

❓ Android 9 and Below - How to Use Encrypted DNS?

Android 9 and below don't natively support Private DNS, need third-party app:

Recommended App: Intra (Google developed)

  1. Download & Install: Search "Intra" on Google Play or APKMirror
  2. Configure 18bit DNS:
    • Open Intra → Settings → Choose "Custom server URL"
    • Enter: https://doh.18bit.cn/dns-query
    • Return to home, enable protection
  3. Verify: Visit https://dtest.18bit.cn/ shows red

Note: Intra uses VPN channel for DoH, may conflict with other VPNs

❓ Will Phone Slow Down After Configuration?

No, may actually be smoother.

  • Disabling telemetry and ad tracking reduces background network requests
  • Disabling background refresh lowers power consumption
  • Encrypted DNS doesn't affect speed (latency difference <10ms)

📚 Further Reading

Official Privacy Documentation

DNS Related Resources

Recommended Tools

  • Password Managers: 1Password, Bitwarden, KeePassXC
  • Open-Source Browsers: Firefox, Brave (built-in ad blocking)
  • Encrypted Messaging: Signal (end-to-end encrypted SMS)

Related Projects


📝 Changelog

Date Version Changes
2025-12 v1.0 Initial release, supports iOS 18, Android 14, HarmonyOS 5, MagicOS 8, HyperOS 2

📧 Feedback & Suggestions

If you encounter any of the following, feel free to submit an Issue or Pull Request:

  • ✅ System updates causing menu path changes
  • ✅ New privacy leak points discovered
  • ✅ Better configuration solutions

⚠️ Disclaimer
This guide is for educational reference only. The author is not responsible for any issues arising from configuration. Please backup important data before configuration.

📌 Final Reminder
Privacy protection is an ongoing process, not a one-time setup. Recommend quarterly reviews and stay informed about system update notes.


If this guide helps you, please give it a ⭐ Star!

中文版本 | English