The_Problem
You hand your phone to a friend to show them a photo. They swipe. You freeze. Somewhere in your camera roll - buried under thousands of holiday snaps and dog photos - was something you'd completely forgotten about.
It's not a shameful thing. It's just private. But your phone doesn't know the difference between a photo you want to share and one you don't.
NuDefndr stays out of your business, works entirely on your phone, and genuinely can't be turned against you.
// Common culprits hiding in your library
None of these make you a bad person. They just deserve to be private.
Our_Approach
Most photo vault apps ask you to trust their servers. Their encryption. Their promise not to look. Even with "end-to-end encryption," if a company controls the keys, they can technically open the vault.
We took a different route. NuDefndr runs entirely on your iPhone using Apple's on-device ML frameworks. The scan happens locally, on your device's neural engine. Nothing is sent anywhere.
Once photos are flagged, you decide what to lock. ChaCha20-Poly1305 encryption - the same standard used in Signal and modern VPNs - secures everything. Your FaceID is the only key.
Detection
Runs on your phone's Neural Engine
No internet. No APIs. No cloud calls. All on-device via SensitiveContentAnalysis
Vault
ChaCha20-Poly1305 + FaceID
We don't hold keys. We can't decrypt it. There's no backdoor. 256-bit
Trust
Open source & auditable
Security researchers can verify every claim we make. GitHub
Core_Principles
Four things we refuse to compromise on. Ever.
All analysis happens locally using iOS CoreML. Your photos never leave your device. The neural network runs on your iPhone's dedicated ML hardware - no internet needed, ever.
ChaCha20-Poly1305 with 256-bit keys - the same standard in Signal and modern VPNs. Vault keys stay in iOS Keychain, protected by your biometrics at the hardware level.
40+ filesystem checks, sandbox probes, and runtime analysis protect against tampering on compromised devices. Security monitoring runs continuously, not just at launch.
We don't have servers to upload to. No cross-device sync. No cloud backup. If you lose your phone, the vault is gone - because that means nobody else can get it either.
Why_Trust_Matters
That's not a marketing line. It's a technical fact. Because encryption happens locally with your biometric key, we never see it. There's nothing to hand over, nothing to breach, nothing to subpoena.
With cloud vaults, you're implicitly trusting a company not to look, a team not to abuse access, and a server farm not to get hacked. We removed every one of those attack surfaces.
The trade-off is real: if you lose your device, your vault is gone too. No password recovery. No master key. That's not a bug - it's the whole point.
// With cloud vaults, you trust:
// With NuDefndr, you trust:
Transparency
We publish the security-critical parts of NuDefndr on GitHub. Not the full app — but the components that matter most for trust.
Vault encryption (ChaCha20-Poly1305), Keychain integration, SensitiveContentAnalysis wrapper, architecture docs, security policy
UI code, business logic, and the full production app are not included. This is a transparency release, not a full open source project.
The published code has not been independently audited. Review it yourself and draw your own conclusions.
The_People
NuDefndr is built by Dro1d Labs - an independent studio making privacy-first apps for iOS and macOS.
We're not a big company with advertisers to keep happy. We don't monetise user behaviour. We have no interest in your data whatsoever - we build tools that work and leave you alone.
NuDefndr is free to download. Core scanning, share protection, and photo review cost nothing and always will. Pro unlocks the full library scan, encrypted vault, auto scan, and advanced tools - available as a monthly, annual, or one-time lifetime purchase.
// Our philosophy, in plain English
We don't want your data
Not even anonymised. Not even aggregate. Zero interest.
No ads, ever
We don't sell attention. The app is the product, not you.
Tools that work and leave you alone
No dark patterns, no engagement hooks, no nudges.
Get_Started
Free. Offline. Open source. No catch.
Download Free on iOSiOS 18+ // SensitiveContentAnalysis // Core ML