Dhvani

Project Description Dhvani is an intelligent, on-device Android application designed to protect vulnerable users from real-time phone and UPI (Unified Payments Interface) scams. Operating on a Sense → Decide → Act → Check architectural framework, the app silently monitors active phone calls and incoming SMS messages, leveraging a hybrid local/cloud AI approach to intercept fraudulent activity before a user can be tricked into transferring funds. The Problem It Solves Social engineering and telephonic financial fraud (impersonation scams, fake lottery wins, panic-induced transfers) are skyrocketing. Existing spam-blocking tools only flag known numbers before a call, leaving users entirely unprotected once a conversation begins. Dhvani bridges this gap by providing active, real-time intervention during the call itself—safeguarding users who are actively being manipulated. How It Works Sense: A background service (CallMonitoringCoordinator and AudioCaptureManager) securely captures real-time call audio alongside incoming SMS messages (detecting OTPs or fraudulent payment requests). Decide: The application runs a continuous evaluation loop. It streams live transcripts to the cloud via Gemini Live for heavy-duty threat scoring while simultaneously running an offline, on-device threat assessment using Gemma (via Google AI Edge LiteRT-LM) to ensure resilience and low latency. Act: If the fused risk score crosses a critical threshold, the app takes immediate control via an Android Accessibility Service. It instantly locks down all UPI payment applications, drops a full-screen threat overlay warning to break the scammer's psychological hold, and triggers haptic alerts. Check: The loop validates that the application lock is successfully maintained. If it detects an bypass attempt, it automatically dispatches an emergency SMS alert to a trusted contact or next of kin. Built natively in Kotlin using Jetpack Compose, LiteRT, and robust Android system-level APIs, Dhvani acts as a bulletproof digital guardian for real-time mobile transaction security.