Built by privacy advocates who believe your documents should stay yours — forever.
PDFLocker exists because everyone — from students to executives — deserves a secure, private, and effortless way to protect their PDF documents online. We built a tool that does one thing exceptionally well: let you PDF password protect online without ever compromising your privacy.
The PDF format is one of the most widely used document formats in the world. From legal contracts and medical records to financial statements and academic research — PDFs are everywhere. Yet, when people needed to add a password to protect sensitive PDFs, the available options were deeply flawed.
Most online PDF tools require you to upload your file to their servers. This creates enormous privacy risks: your confidential documents are transmitted over the internet, stored on third-party servers, processed by unknown systems, and in some cases, retained permanently. For professionals handling sensitive information, this is simply unacceptable.
Desktop PDF software that includes encryption features often costs hundreds of dollars per year. Open-source alternatives are technically complex and inaccessible to non-technical users. The gap between "secure" and "accessible" was wide — and that's exactly the gap PDFLocker was designed to close.
PDFLocker was built around a fundamental principle: your files should never have to leave your device to be protected. By leveraging modern browser capabilities — specifically the JavaScript-based pdf-lib library — we built a tool that performs all PDF encryption operations directly within your browser.
When you use PDFLocker, your PDF file is read by your browser's file API, processed entirely in memory using client-side JavaScript, encrypted with AES-256 standard encryption, and immediately available for download as a protected file. At no point does your original file, your password, or any metadata leave your computer. We have no servers involved in the process — not because we're cutting corners, but because we deliberately architected our solution this way.
There are many online PDF tools, but PDFLocker takes a fundamentally different approach in three key areas:
Privacy by Architecture: We didn't just add a privacy policy — we built privacy into the architecture itself. When there are no file uploads, there can be no data breaches, no unauthorized access, and no server-side vulnerabilities. This isn't a feature, it's a foundational design decision.
No Business Model Around Your Data: Many "free" tools are only free because they monetize your data or your files. PDFLocker is genuinely free because we keep our infrastructure minimal — a static website with client-side processing requires no expensive server infrastructure, so we can afford to offer it for free with no strings attached.
Transparency: We use well-known, open-source libraries (pdf-lib). There is no proprietary black box processing your files. The security community can audit the tools we rely on, and you can inspect what happens in your browser using developer tools.
Every product decision starts with the question: "Does this protect our users' privacy?" Privacy isn't a checkbox for us — it's the foundation of everything we build.
Security tools should not be gated behind paywalls. We believe strong PDF encryption should be accessible to everyone, everywhere, at no cost — a right, not a premium feature.
Powerful security tools don't have to be complicated. We obsess over user experience to ensure that protecting a PDF takes seconds, not minutes, regardless of technical skill level.
We are transparent about how our tool works, what data we collect (none), and why we make the technical choices we do. No hidden agendas, no dark patterns.
A small, passionate team of developers, designers, and security advocates dedicated to privacy-first software.
10+ years building web security tools. Passionate about making enterprise-grade security accessible to everyone.
Believes great security UX can be beautiful. Makes complex encryption tools feel effortlessly simple.
Cybersecurity expert ensuring PDFLocker meets and exceeds the highest encryption standards.
Join thousands of users who trust PDFLocker to keep their documents private and secure.
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