Python Antivirus V4.0: Design and Implementation of a Multi-Layer Desktop Security Application

This paper presents the design, architecture, and implementation of Python Antivirus V4.0, a desktop-based
cybersecurity application built using Python and PyQt5. The application delivers a layered threat detection strategy
combining local SHA-256 signature-based detection against curated hash packs with optional cloud API
enrichment via VirusTotal and MetaDefender. V4.0 introduces several notable enhancements over its predecessors:
a responsive, thread-safe scanning engine using QThread, a persistent JSON-backed scan history module with
color-coded verdicts, CSV and PDF report export capabilities powered by ReportLab, a structured quarantine
system with restore and permanent deletion support, a batch folder scanning mode, and a real-time file monitoring
subsystem driven by Watchdog. The graphical interface supports dark and light theming through configurable
stylesheets. Evaluation of the application demonstrates its effectiveness as a lightweight, portable, and extensible
endpoint security tool suitable for educational, research, and small-office deployment contexts.
Keywords — Antivirus Software, SHA-256 Hashing, PyQt5, VirusTotal API, MetaDefender, Quarantine, Realtime
Monitoring, Cybersecurity, Python, Desktop Application.