Location Validation and Server Time Synchronization for iOS-Based Attendance to Mitigate ASN Fraud in Lamongan

Abstract

The rapid advancement of information technology has driven government institutions to adopt digital attendance systems to improve the effectiveness of attendance management for Civil Servants (ASN). The Lamongan Regency Government has implemented an Android-based attendance application, but no equivalent service is available for iOS users, creating unequal access to digital attendance services among employees who use different devices. This study designs and implements an iOS-based attendance application equipped with geofencing-based location validation and server time synchronization to improve attendance-data accuracy and reduce the risk of fraud such as location or time manipulation. The application was developed using the Flutter framework and integrated with a Laravel REST API and a MySQL database for authentication, data storage, and real-time communication. Testing results show that the application successfully performs authentication, location validation, server time synchronization, and check-in/check-out processes according to the defined rules. Black-box testing confirmed that all functions operated as expected, geofencing testing verified that attendance could only be recorded within the designated work area, and GPS-spoofing testing showed that spoofed locations outside the designated radius were rejected, while spoofed coordinates placed inside the radius were accepted, indicating that the current geofencing mechanism validates reported coordinates rather than detecting spoofing itself. A System Usability Scale (SUS) evaluation yielded a score of 77.02 (Good), indicating that the application is easy to use. These results demonstrate that the proposed application supports more accurate, secure, and consistent attendance recording for Civil Servants.