VoiceShield

VoiceShield is an AI-assisted call safety application designed to help users stay aware of potential voice manipulation (synthetic or altered voices) and voice phishing risks during phone calls.

The app analyzes limited audio characteristics locally on the device in real time during calls.
When potentially suspicious patterns are identified, VoiceShield displays a small on-screen alert to help users remain cautious.

VoiceShield provides informational assistance only and may not detect all threats.

🔍 1. Service Overview
VoiceShield operates as a supportive safety tool during phone calls.
It monitors audio-related patterns in real time and provides visual alerts when indicators associated with voice manipulation or phishing attempts are detected.

All analysis is performed on-device, and call audio is not transmitted or stored externally.

🔐 2. Key Features

2.1 Voice Manipulation (Synthetic Voice) Indicators
Detects abnormal audio patterns that may be associated with synthetic or altered voices and provides alerts when identified.

2.2 Voice Phishing Risk Signals
Analyzes conversational risk indicators and presents visual guidance such as Low / Caution / High risk levels.

2.3 On-Screen Overlay Alerts
Displays small, non-intrusive alert cards on top of the call screen for immediate awareness.

2.4 On-Device Processing
Audio analysis is performed locally on the user’s device.
Call audio is not uploaded, stored, or processed on external servers.

🧩 3. Accessibility Service Usage Notice
VoiceShield uses Android’s AccessibilityService API solely to detect call start and end events and to display on-screen alerts during calls.

Accessibility service is used only for the following purposes:
- Detecting phone app screen state changes (e.g., call started or ended)
- Automatically triggering AI analysis during active calls
- Displaying small overlay alert cards for user awareness

Accessibility service is never used to:
- Read or store on-screen text (messages, chats, passwords, etc.)
- Collect keystrokes, touch input, or user interaction data
- Modify other apps, block user actions, or serve advertisements
- Operate in a hidden or deceptive manner

VoiceShield is not an accessibility tool for disability assistance.
Users can disable the service at any time in system settings.

🔒 4. Privacy & Data Protection

VoiceShield complies with Google Play policies and applicable data protection regulations, using only the minimum data necessary for operation.

Data processed:
- Audio data: analyzed locally in real time and immediately discarded (no server transmission)
- Analysis results (e.g., risk scores): may be used in a non-identifiable form to improve service quality
- Device information (OS, model): for error analysis and support
- Account information: for login and user management

Data not collected:
Messages, photos, videos, files, contacts, call recordings, or personal content.

Privacy Policy:
https://www.metacrowd.ai/terms-sg?tab=privacy

Account Deletion:
https://www.metacrowd.ai/acc_delete_sg

🎧 5. Permissions Explanation

Microphone (RECORD_AUDIO)
Required for real-time audio feature analysis (no recording or transmission)

Phone State (READ_PHONE_STATE)
To detect call start and end events

Overlay (SYSTEM_ALERT_WINDOW)
To display alert cards during calls

Foreground Service (Microphone)
To ensure continuous analysis during active calls

Notifications (POST_NOTIFICATIONS)
To provide alerts when the screen is off

⚠️ 6. Important Notes
All analysis results are for informational purposes only.
VoiceShield cannot detect all voice manipulation or phishing attempts.
Users should verify suspicious calls directly with official institutions.
This app does not provide legal or financial advice.

VoiceShield is designed as a privacy-focused, on-device safety assistant
to support informed decision-making during phone calls.