We built LOCKED App to deliver genuine privacy protection. By focusing on military-grade encryption, intuitive design for all technical levels, and aggressive ASO, we achieved 1.8M+ installs, and maintained 4.8-star ratings across 39K+ reviews.
In a digital landscape where privacy concerns grow daily, I identified an opportunity to deliver genuine security with an intuitive user experience. I reached out to an extremely talented coder from Asia to collaborate on a new privacy-focused project.
The result was LOCKED App: a mobile secret vault designed to protect users’ private photos, videos, and files using military-grade AES encryption. Beyond the vault, it offers a discrete fake calculator interface, a privacy browser, secret notes, and other features so people can safeguard information without sacrificing ease of use.
Time to market: 5 months
Project lifetime: May 2019 – Feb 2025
The Challenge
Extreme Market Saturation. Hundreds of similar vault applications competed for the same users, many with established user bases and substantial marketing budgets.
Unethical Competitor Tactics. We encountered systematic blackhat marketing from rivals, including trademark infringement, false abuse reports, fake reviews, and even unethical hacking attempts.
Limited Financial Resources. As a bootstrapped venture, we faced tight budget constraints while competing against well-funded competitors.
Diverse User Technical Proficiency. Our target audience spanned all technical ability levels, many struggling with basic mobile functions, requiring an interface that balanced sophistication with simplicity.
High Customer Acquisition Costs. The privacy app vertical had relatively high CPAs, making traditional paid growth strategies challenging for our limited budget.
The Solution
Locked App
Your secret vault
Project Details
User Experience
- Designed an intuitive, clean interface that even less tech-savvy users could navigate easily.
- Implemented progressive onboarding that educated users while minimizing friction.
- Established clear visual hierarchies and minimal cognitive load in all interactions.
- Rigorously tested with diverse user groups to ensure accessibility across technical proficiency levels.
Product Development
- Built military-grade AES encryption (the standard used by governments and financial institutions) to provide genuine security, not just marketing claims.
- Developed multiple security layers including PIN protection, pattern locks, and fingerprint authentication.
- Created innovative features like Calculator Mode, Privacy Browser, Secret Notes, Fake Vault, and Intruder Selfie to provide more holistic experience.
Marketing Strategy
- Employed advanced App Store Optimization (ASO) methods, leveraging keyword strategy, TF-IDF, and NLP metrics to position our app effectively. This included thorough competitor analysis, sentiment optimization, and use of LSI terms.
- Developed a comprehensive SEO strategy to get organic traffic from search engines to the app’s official website.
- Deployed targeted paid acquisition focusing on channels with high efficiency.
- Collaborated with influencers to gather honest and impactful reviews;)
- Continuously improved conversion funnels through systematic A/B testing.
The Impact
1.8+ Million Installs
The app achieved almost two million downloads, demonstrating broad reach, strong demand, and consistent user adoption over time.
4.8-Star Rating
Based on 39K+ reviews, the app maintained a high user satisfaction rating, indicating a positive user experience. Users frequently praised the app’s ease of use and clean, intuitive user interface.
Top 3 Search Rankings
LOCKED App consistently ranked in the top three positions for highly competitive keywords in Google Play search, driving organic traffic.
The app attracted a significant amount of organic traffic from search alone, showcasing the effectiveness of the ASO strategy.
Strong Traction + Improved AOV
Through continuous A/B testing and marketing tweaks, we raised Average Order Value from $4.32 to $7.01. At the same time, the app kept 90% of users coming back (vs. ~73% for similar apps) and reached ~20% DAU/MAU (vs. ~10% for peers), showing much stronger engagement and retention than the market.
Top-Grossing Listing
After 5 months from launch, the app achieved top-grossing status on Google Play, demonstrating sustainable growth and strong market fit.
What Users Say
Reviews from Google Play Store
However, the market evolved around us. As more Android-based systems integrated comparable features directly into their core – without cost or advertising – our competitive edge eroded. Sustaining the project financially while competing against native OS functionality became untenable. In early 2025, after six years, we made the decision to wind down the project.
LOCKED Vault App demonstrated that even in a crowded market, a commitment to quality, user privacy, and strategic execution can lead to significant growth and a strong market position.