Security Articles

Android SELinux Access Control Architecture: sepolicy Compilation, Domain Transitions, and neverallow Auditing

Starting from an avc denial log, this article systematically walks through Android SELinux's sepolicy compilation pipeline, domain transitions, contexts mapping, and neverallow auditing, with native service troubleshooting and practical advice.

On-Device AI Prompt Injection and Defense in Depth

How prompt injection, jailbreaks, and tool-call side effects threaten on-device AI, plus a four-layer defense from input classifiers to Native-layer data masking.

Android Play Integrity API: Nonce Validation and Device Risk Scoring

A field-tested guide to Play Integrity API migration, covering device, app, and account integrity signals, nonce replay protection, server-side verification, retry behavior, and risk-based decisions.

Android Secure Surfaces: FLAG_SECURE, SurfaceFlinger, and DRM

A practical deep dive into Android content protection, covering FLAG_SECURE, SurfaceFlinger protected overlays, Widevine DRM, and Compose pitfalls.

APK Decompilation and Recompilation: From Basics to Practical Workflows

A practical guide to Android APK decompilation, modification, recompilation, AAR dependency integration, and APK signing with apktool and related tools.

Android App Security Hardening: Attack and Defense in Practice

A practical guide to Android app hardening, covering reverse engineering, code protection, RASP, network security, secure storage, and security coding practices.