File, Image or Text Locker Online Free

Q: What happens if I forget the password?

Since no passwords are stored anywhere, there is no way to recover a forgotten password. Make sure to remember or securely store your password before locking any content.

Q: Can I share the locked file with someone?

Yes. Download the locked .html file and share it via email, WhatsApp, or cloud storage. When opened in any browser, it prompts for the password to reveal the content.

Q: Does the locked file work on mobile devices?

Yes. This tool generates a safe self-opening HTML format that works seamlessly across all modern mobile browsers including Chrome, Safari, Firefox, and Edge.

Lock any file, image, or text with a strong password -- entirely inside your browser. This tool uses AES-256 encryption. No data is ever uploaded to any server. Your generated locked file is safe to share on WhatsApp or Email without crashing your device!

Quick Answer This free online locker encrypts files, images, and text with a password using military-grade AES-256 right in your browser. No server uploads. It generates a safe self-opening HTML file that you can easily share. The recipient simply opens the file and enters your password to view the original content.

Drag and drop your image here, or click to browse

Supports JPG, PNG, GIF, WEBP, BMP, SVG (Max 50 MB)

Set Password

Encrypting...

File Locked Successfully!

Your content has been encrypted securely.

How to Use This Tool

Choose Content Type -- Select Image, File, or Text from the three tabs at the top of the tool.

Add Your Content -- Upload an image or file using drag-and-drop or the browse button, or type your secret text into the text area.

Set a Strong Password -- Enter a strong password in the password field. This password will be required to unlock the content later.

Generate Locked File -- Click the "Generate Locked File" button to encrypt your content with AES-256 encryption.

Download or Share -- Download the safe encrypted .html file or share it directly. The recipient opens it in any browser to unlock with password.

Unlock the File -- Switch to the Unlock tab, upload the locked file, enter the correct password, and securely view or download your original content.

Features

AES-256-GCM Encryption

Military-grade encryption standard used by banks and governments worldwide for maximum security.

100% Browser-Side

All processing happens in your browser. No files, text, or passwords are ever sent to any server.

Multi-Format Support

Lock images, documents, PDFs, audio, video, or any file type. Also supports plain text encryption.

Easy & Safe Sharing

Files are saved as safe self-opening HTML files so mobile devices won't crash when opening them in WhatsApp or Email.

Password Strength Meter

Built-in password strength indicator helps you choose a secure password before locking your content.

Works Everywhere

Fully responsive and works perfectly on Chrome, Firefox, Safari, Edge on desktop, tablet, and mobile.

Tips and Common Mistakes

Never forget your password. Since nothing is stored on any server, a forgotten password means your locked content is permanently inaccessible.
Share passwords securely. Do not send the locked file and its password through the exact same message. Use a separate secure method for the password.
Check file size before locking. Very large files (over 50 MB) may cause slowdowns on older mobile devices since encryption happens in the browser's memory.

Frequently Asked Questions

Is my data uploaded to any server?

No. All encryption and decryption happens entirely inside your browser using the Web Crypto API. No files, text, or passwords are ever sent to any server. Your data never leaves your device.

What encryption algorithm does this tool use?

This tool uses AES-256-GCM encryption via the browser's built-in Web Crypto API. This is the same standard used by banks, governments, and security professionals worldwide for protecting sensitive information.

What happens if I forget the password?

Since no passwords are stored anywhere -- not on our servers, not in the file -- there is no way to recover a forgotten password. Make sure to remember or securely store your password before locking any content.

What file types can I lock?

You can lock any file type including documents, spreadsheets, PDFs, images, audio files, video files, and more. On the Image tab, common image formats like JPG, PNG, GIF, WEBP, BMP, and SVG are specifically accepted.

Is there a file size limit?

The tool works entirely in your browser memory, so practical limits depend on your device. Files up to 50 MB work reliably on most modern devices. Very large files may slow down older devices or devices with limited RAM.

Can I share the locked file with someone?

Yes. The tool saves your encrypted data as a self-opening HTML file (.udlock.html). You can share it via WhatsApp or email. The recipient simply opens the file in Chrome/Safari to unlock it with your password.

Does the locked file work on mobile devices?

Yes! We updated our system to ensure generated files work perfectly across all Android and iPhone devices without crashing or attempting to open incompatible apps (like AR viewers). The unlocking process works on Chrome, Safari, Firefox, and Edge.

Is this tool really free?

Yes, this tool is completely free to use with no hidden charges, no sign-up required, and no usage limits. It is part of the UD Tools free utilities platform and will remain free.

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Developed By

Muhammad Usman

Founder, Developer & CEO

Building free, fast, and practical web tools for everyday users — from image converters to text utilities, designed to solve real problems without ads getting in your way.

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