NuDefndr — Core Privacy Components

NuDefndr is a privacy-first iOS app for detecting and securing sensitive content in your photo library—entirely on-device. This repository contains auditable security components used by the app (proprietary UI and business logic are closed-source).

Quick links: nudefndr.com · App Store · Dro1d Labs Limited

---

Table of contents

• What is NuDefndr?
• Privacy Guarantees
• Repository Components
• Security Architecture
• Running Tests & Build
• Contributing
• Contact

---

What is NuDefndr?

NuDefndr scans your iPhone photo library for sensitive, explicit, or NSFW content using Apple’s on-device machine learning—no cloud processing, no data transmission, no tracking.

Core features

• On-Device Detection — Uses Apple's SensitiveContentAnalysis framework (iOS 17+)
• Encrypted Vault — AES-256 + ChaCha20-Poly1305 encryption (hardware-backed). See /Vault/VaultCrypto.swift for implementation.
• Panic Mode — Dual-vault system with emergency concealment
• Background Scanning — Automatic protection with incremental updates
• Zero Network Activity — 100% local processing (verifiable)

Who it's for: parents, individuals protecting sensitive photos, privacy-conscious users, and security researchers.

---

🔒 Privacy Guarantees

NuDefndr enforces strict, verifiable privacy controls:

Guarantee	Implementation	Verification
Zero network transmission	No URLSession calls in analysis pipeline	Inspect Security/SensitiveContentService.swift
100% on-device processing	Apple SensitiveContentAnalysis only	iOS 17+ framework requirement
Hardware-backed encryption	Keys stored in Secure Enclave	Vault/VaultCrypto.swift + Vault/KeychainSecure.swift
No analytics/tracking	No telemetry in detection flow	Audit /Security directory

How to verify: review the files listed in the Repository Components section, run the tests, and inspect network logs during a scan.

---

🧱 Repository Components

This repository exposes the auditable privacy and security architecture. It is not a complete app.

Core analysis engine

• SensitiveContentService.swift — Apple SensitiveContentAnalysis wrapper with batch processing
• ScanRangeOption.swift — Immutable scan range definitions (7 days, 30 days, etc.)

Security & encryption

• Vault/VaultCrypto.swift — AES-256 + ChaCha20-Poly1305 encryption
• Vault/KeychainSecure.swift — Secure Enclave key derivation and lifecycle management
• Security/JailbreakDetection.swift — 10-vector jailbreak detection
• Security/AntiTampering.swift — Code signature validation and integrity checks

Panic mode

• PanicMode/PanicModeEngine.swift — Dual-vault architecture for emergency concealment
• PanicMode/PanicModeConfig.swift — Configuration and decoy vault management

Tests & docs

• Tests/CryptoTests.swift — Cryptographic unit tests
• Tests/SecurityTests.swift — Jailbreak detection and anti-tampering validation
• Docs/SECURITY.md, Docs/PERFORMANCE.md, Docs/THREAT_MODEL.md, Docs/SecurityArchitecture.md

---

🧱 Security Architecture (summary)

User Photo → Authentication Required → Retrieve Key from Keychain → Secure Enclave Key → VaultCrypto (AES-256-GCM or ChaCha20-Poly1305) → Encrypted Blob + Nonce + Auth Tag → Write to App Container (Encrypted)

Key lifecycle highlights

1. App install → generate 256-bit symmetric key
2. Device-bound key derivation
3. Keychain storage with kSecAttrAccessibleWhenUnlockedThisDeviceOnly + biometric protection
4. Key zeroization on deallocation

---

🧪 Running tests & build

Run tests:

swift test --filter CryptoTests
swift test --filter SecurityTests
swift test --filter PerformanceBenchmarkSuite

Quick build (Swift Package Manager):

swift build
swift test

Tests include AES-256 and ChaCha20-Poly1305 round-trips, PBKDF2 consistency, entropy checks, timing-attack resistance, jailbreak detection, and anti-tampering checks.

---

🚀 Performance highlights

Version 2.0+ incremental scanning provides significant speed and battery improvements (see Docs/PERFORMANCE.md for full benchmarks).

---

🤝 Contributing

We welcome security research and documentation improvements. Do not open public issues for security vulnerabilities — report privately to security@nudefndr.com with a description, PoC (if safe), steps to reproduce, and impact assessment.

See CONTRIBUTING.md for guidelines.

---

📞 Contact

• Website: https://nudefndr.com
• App Store: https://apps.apple.com/de/app/nudefndr/id6745149292
• Support: support@nudefndr.com
• Security: security@nudefndr.com

---

Version: 2.1.7 Last Updated: January 2026 Maintained by: Dro1d Labs Limited