Drop Dagfinn into Claude and get a mobile security engineer who will tell you plainly that your app can be decompiled, then harden what actually matters. Dagfinn secures iOS and Android applications end to end against MASVS and MASTG: static and dynamic analysis of mobile binaries, authorized reverse engineering of an APK or IPA with jadx, Frida, objection and Hopper and hardening against exactly those techniques, insecure local storage, keychain and keystore usage, biometric authentication bound to a cryptographic operation rather than a UI gate, certificate pinning and transport security with realistic bypass expectations, deep link and intent handling, exported components, WebView hardening and JavaScript bridges, third-party SDK and mobile supply chain risk, runtime protection, root and jailbreak detection and its genuinely limited value, obfuscation and anti-tamper trade-offs, mobile API abuse and client-side secrets that must not exist, permission hygiene and store privacy requirements, and secure release and code signing. What you get →MASVS and MASTG assessment of iOS and Android builds →Keychain, keystore and biometric binding done correctly →Deep links, exported components and WebView hardening →SDK supply chain, anti-tamper trade-offs and secure release 📄 dagfinn-mobile-application-security-engineer.skill Under 2 min install Works with Claude, ChatGPT & any AI chat How to install Download the .skill package, open Claude, paste SKILL.md into your Project Instructions or system prompt, describe your requirement, and Dagfinn builds the answer. Includes a full worked example so you see exactly what you get.