Encrypted life vault mobile app with zero-knowledge encryption and on-device AI assistant
STEALTH MODE

Zero-Knowledge
Encryption Meets On-Device AI. The Private Everything App.

ProductCrafters built an encrypted AI life vault for a San Francisco startup, combining secure notes, passwords, document storage, and a patented on-device LLM into one privacy-first platform.

Headquarters

United States

Industry

Privacy & Security

Partnership

2019 - Present

Services

iOS Development

Android Development

Backend Development

AI/ML Integration

Dedicated Team

About the Client

Stealth-Mode Privacy Startup

A San Francisco-based technology company focused on building the future of private, personal organization. With a vision to give people complete control over their digital lives, they're redefining what's possible when privacy and powerful features coexist. We've partnered for over 5 years, expanding our dedicated development team from 1 to 8 engineers as the product evolved from concept to a feature-rich platform with thousands of active users.

Results

5+ years

Long-term partnership

1→8 team

Developers, QA, PM

4.3★

App Store rating

10+ apps

Consolidated into one platform

Goal & Outcome

Goal

People struggle to organize their digital lives across dozens of apps—notes in one place, passwords in another, documents scattered, health records inaccessible. Meanwhile, privacy concerns grow as tech companies monetize user data.

Our San Francisco-based client envisioned a revolutionary solution: a single encrypted app consolidating 10+ separate tools while ensuring complete user privacy through zero-knowledge architecture. The challenge was building this technically complex platform while maintaining the simplicity users expect from consumer apps.

Outcome

We built an encrypted AI everything app using our mobile app development and AI integration expertise—combining secure notes, password management, document vault, and a patented on-device LLM into one seamless experience.

Through our dedicated team approach, we've grown from 1 developer to a team of 8 over 5+ years, continuously evolving the platform with zero-knowledge encryption ensuring not even the company can access user data.

Brian Taylor, Taylor Equities

Brian Taylor

Founder at Thinkspan

Brian Taylor

They're boutique and have intelligent and talented employees that work efficiently. We're currently doubling our engagement. Also, they don't feel like a hired contractor, they're part of our team.

5.0

16 reviews

View on Clutch

Key Features We Built:

True Zero-Knowledge Encryption

End-to-end encryption where only users hold the keys. Encryption keys never leave the device. Real-time encrypted backups sync across devices while maintaining complete privacy. Not even the company can access user data—ensuring absolute data ownership.

Patented On-Device LLM

Built patented edge AI assistant processing data directly on the device. The LLM learns from user documents to generate custom reminders and personalized insights—understanding personal context like medical conditions and important dates—all without any data leaving the device.

Encrypted Document Vault

Scan, upload, and organize important documents—from wills and contracts to medical records and insurance cards. All encrypted, searchable, and accessible only by the user with their private keys. Built-in document scanner with OCR for instant digitization.

Private Health Dashboard

Store medical records, prescriptions, and even DNA sequencing data in a zero-knowledge environment. A secure health repository where sensitive health information remains completely inaccessible to anyone but the user. Integration with Apple Health and Google Fit.

Need a Rewards Platform?

We build gaming apps, loyalty programs, and reward systems from MVP to scale — with 6M+ users across our projects.

Need a Rewards Platform?
Decore AI

Private Encryption

01

Capture Everything

Users store all their personal information in one secure place: quick notes and to-dos, passwords and login credentials, scanned documents and PDFs, photos and videos, health records and DNA data, family information and contacts. Everything is encrypted locally before being stored.

02

AI Learns Privately

Our patented edge AI architecture runs a large language model directly on your device. The LLM reads your documents, notes, and health records to understand your personal context—medical conditions, important dates, financial details, family information. All processing happens locally using Core ML (iOS) and TensorFlow Lite (Android) with zero third-party access.

03

Smart Insights

The on-device AI generates custom reminders based on your documents ("Take medication at 8am based on prescription"), provides intelligent answers from your personal data ("When is mom's birthday?"), creates summaries of long documents, and suggests actions based on patterns—all without any data leaving your device.

04

Sync Securely

Data syncs in real-time across iPhone, iPad, and Android devices using end-to-end encryption. Your information travels encrypted through cloud servers that cannot read the content. Each device has its own encryption keys derived from your master password. If you lose your device, everything is safely backed up—but only you can decrypt it.

05

Share Selectively

Share specific items with family members while maintaining complete control. Perfect for families managing shared information securely: share health insurance details with spouse, give kids access to passwords they need, share important documents with trusted contacts. Each share is individually encrypted and can be revoked anytime.

From Fragmented to Unified Privacy

Before

Traditional Process

10+ separate apps
Notes, passwords, documents, photos all in different apps
Privacy concerns
Data mined by tech companies, no control over personal information
Cloud-dependent AI
AI assistants send all data to external servers for processing
Fragmented experience
Switching between apps disrupts workflow and productivity
Vendor lock-in
Data trapped in proprietary formats, difficult to export or migrate
After

Digital Solution

All-in-one platform
Notes, passwords, vault, health data, AI assistant—unified experience
Zero-knowledge encryption
Only you can access your data, not even the company
Patented on-device LLM
AI processes data locally on your device, never sent to servers
Seamless workflow
Everything in one place with intelligent cross-feature integration
Complete data ownership
Export everything, full control over your digital life

Under the Hood

Mobile & Core Tech

Native iOS development with Swift, Android apps with Kotlin, and cross-platform solutions using React Native. Backend powered by Node.js with TypeScript, plus TensorFlow Lite for on-device machine learning.

Swift

Swift

Kotlin

Kotlin

React Native

React Native

Node.js

Node.js

TypeScript

TypeScript

TensorFlow

TensorFlow

FaQ

How much does it cost to build an encrypted mobile app?

Encrypted mobile app development costs vary based on security requirements, platform (iOS/Android), and features. Basic encrypted apps with password management start at $80,000-$120,000. Complex apps with on-device AI, zero-knowledge encryption, and multi-feature platforms like our encrypted life vault typically range from $200,000 to $500,000+. Learn more about our mobile app development services. We offer free consultations to provide accurate estimates.

What is zero-knowledge encryption?

Zero-knowledge encryption means your data is encrypted on your device before it ever reaches our servers. Only you hold the encryption keys—not even the app company can access your data. This architecture ensures complete privacy: even if servers are breached, attackers only see encrypted data they cannot read. It's the gold standard for privacy-focused applications.

Can AI work on-device without sending data to the cloud?

Yes, on-device AI (also called edge AI) runs machine learning models directly on your phone or tablet. We've built patented on-device LLM systems that process data locally using Core ML (iOS) and TensorFlow Lite (Android). The AI learns from your documents and generates insights without any data leaving your device or being sent to third-party servers. This is critical for privacy-sensitive applications.

How long does it take to build a privacy-first mobile app?

Development timelines depend on complexity. A basic encrypted app with password management takes 4-6 months. Complex privacy platforms with on-device AI, document management, and cross-device sync (like our encrypted life vault) typically require 12-18 months for initial launch. Our 5+ year partnership with this client demonstrates the ongoing evolution and feature expansion of successful privacy platforms.

What's the difference between end-to-end encryption and zero-knowledge encryption?

End-to-end encryption protects data in transit (between sender and receiver), but the service provider may still access data on their servers. Zero-knowledge encryption goes further: your data is encrypted on your device before reaching servers, and encryption keys never leave your device. The service provider literally cannot access your data—they have zero knowledge of it. This is essential for true privacy.

Can encrypted apps sync across multiple devices?

Yes, encrypted apps can sync securely across devices. We implement end-to-end encrypted sync where data travels encrypted between your devices through cloud servers that cannot read the content. Each device has its own encryption keys, and data remains encrypted at rest on servers. This enables seamless multi-device experience while maintaining zero-knowledge architecture.

How do you ensure mobile app security beyond encryption?

We implement defense-in-depth security: zero-knowledge encryption for data at rest and in transit, secure enclave integration for biometric authentication and key storage, code obfuscation to prevent reverse engineering, certificate pinning to prevent man-in-the-middle attacks, regular security audits and penetration testing, and secure coding practices following OWASP mobile security guidelines.

What is on-device AI and why is it more secure?

On-device AI processes data directly on your phone/tablet without sending it to external servers. Machine learning models run locally using device hardware. This is more secure because your personal data never leaves your device, there's no third-party access or data mining, it works offline without internet connection, and it provides instant results without network latency. Our patented on-device LLM demonstrates this technology at scale.

Do you build apps for both iOS and Android?

Yes, we develop native iOS apps (Swift), native Android apps (Kotlin), and cross-platform apps (React Native). For high-security applications, we often recommend native development for better security integration with platform features like secure enclave, biometric authentication, and hardware-level encryption. Our team has deep expertise in both platforms and can recommend the best approach for your requirements.

Can you help with App Store and Google Play submission?

Yes, we handle the complete app submission process including preparing app store listings, creating screenshots and promotional materials, managing App Store Connect and Google Play Console, navigating review processes and addressing rejections, and implementing app store optimization (ASO). We've successfully launched dozens of apps and understand platform requirements and review guidelines thoroughly.

Ready to build your privacy-first mobile app?

Book a consultation

From our offices in Europe, we serve startups and enterprises globally, delivering encrypted mobile applications with zero-knowledge architecture and on-device AI. Our international team provides 24/7 development coverage and deep expertise in iOS, Android, and privacy-first technologies.

ProductCrafters global presence map
Click to enlarge

Our offices

🇵🇹

Portugal

Cascais

🇺🇦

Ukraine

Proskurivska 45, Khmelnytskyi

🇪🇪

Estonia

Kaupmehe tn 7-120, Tallinn, 10114

bg
Risk-Free Start

Your Free Trial Sprint

1
Week 1

Meet your team

Slack channel, assigned developer, daily standups. First code committed to your GitHub.
2
Week 2

Working prototype delivered

Technical spike or prototype complete. Architecture + budget roadmap for the full build.

You keep everything. Zero cost. Zero commitment.

Oleg Kalyta

Oleg Kalyta

Founder & AI Lead
What happens next:
  • 1.You submitWe review within 24 hours
  • 2.15-minute scoping callWe align on trial goals
  • 3.Developer assignedWithin 48 hours
  • 4.Working code in your repoBy end of Week 1

Start Your Free Trial Sprint

Tell us about your project and we'll get back to you within 24 hours.

No contract. No credit card. You keep everything we build.

Oleg Kalyta

Oleg Kalyta

Founder