SafeCircle

Smartphone theft and unauthorized access represent significant threats to personal data security and digital privacy.Most contemporary anti-theft systems rely on internet connectivity and cloud-based infrastructures, making them ineffective when network services are disabled.This paper presents SafeCircle, a secure SMS based offline mobile antitheft framework designed to provide authenticated remote device control without internet dependency.The proposed system integrates trusted contact validation, cryptographic PIN hashing, Android Device Administration APIs, and secure local storage mechanisms to execute remote commands such as device locking, alarm triggering, GPS location retrieval, and data wiping.A modular layered architecture ensures separation of concerns and improved scalability.Experimental evaluation demonstrates low latency command execution (average 2.6 seconds), minimal battery overhead, and reliable operation in offline environments.Comparative analysis highlights SafeCircle's advantages over cloud-dependent tracking systems.The framework contributes a resilient, lightweight, and secure alternative for real world mobile security scenarios.