An Android app that protects elderly users from coercion scams — specifically the "Digital Arrest" fraud pattern, where a caller impersonates law enforcement or government officials and keeps victims on the phone while forcing them to transfer money through GPay or NetBanking.
Hackathon submission — AI for Social Good / Cybersecurity track.
Truecaller and spam blockers work on numbers. They can't help when the call itself sounds legitimate. Digital Arrest scams are effective precisely because the conversation is the weapon — the fraudster just needs to keep the victim scared and on the line long enough to authorize a transfer. By the time the call ends, the money is gone.
The core insight is behavioral: opening a payment app while actively on a phone call is, for elderly users, almost always a sign of coercion rather than coincidence. SilverGuard watches for that pattern specifically.
IF (phone call is active) AND (banking/payment app is opened)
THEN trigger critical alert
When the pattern fires, a full-screen overlay interrupts the flow and an alert is sent to a registered family member over Gmail.
Text analysis runs in parallel — the app reads on-screen content from WhatsApp and SMS, scoring for keywords common in these scams ("OTP", "Police", "RBI", "arrest", "urgent"). Flagged messages are verified against Groq's LLaMA-3 model before triggering an alert.
- Coercion Interlock — detects simultaneous active call + payment app usage via
TelephonyManagerandAccessibilityService - Text analysis — scans WhatsApp and SMS for high-risk keyword patterns, LLaMA-3 used for secondary verification
- Blocking overlay — full-screen interrupt that breaks the scam flow and tells the user what's happening
- Family alert — sends a Gmail notification to a registered contact via N8N webhook when a critical event fires
- App — Flutter (Dart)
- Native modules — Kotlin (
AccessibilityService,TelephonyManager) - AI — Groq API (LLaMA-3-70b)
- Automation — N8N (webhook → Gmail)
- Install the APK and grant Accessibility and Overlay permissions.
- Test text detection — open WhatsApp and type "This is urgent OTP". The overlay should trigger.
- Test Coercion Interlock — make an active phone call to the device, then open Google Pay while still on the call. The critical alert fires immediately.
MIT