How do I encrypt a file online for free?

Open a browser-based encryption tool. Drop any file into it. Enter a password. The tool encrypts the file using AES-256-GCM directly in your browser and gives you a .enc file to download. Your original file never leaves your device — no upload to any server. To decrypt later, open the same tool, drop the .enc file in, enter the same password.

Is it safe to encrypt files in a browser?

Yes, if the tool runs entirely in your browser without uploading the file. Look for tools that use the Web Crypto API — a built-in browser feature that performs encryption locally on your device. If the tool uploads your file to a server, that adds risk. A browser-based tool that processes everything locally is as secure as desktop encryption software.

What does AES-256 mean?

AES-256 is the Advanced Encryption Standard with a 256-bit key. It is the same encryption standard used by governments and militaries worldwide. A 256-bit key has 2^256 possible combinations — it would take billions of years for the fastest computers to try all combinations. It is the strongest widely-used encryption available.

What file types can I encrypt?

Any file type. PDFs, images, videos, documents, spreadsheets, archives, executables — the tool encrypts the raw bytes regardless of format. The encrypted output has a .enc extension. The original file type is preserved inside the encryption and restored when you decrypt.

What happens if I forget the password?

The file cannot be recovered. There is no password reset, no recovery key, no backdoor. This is by design — it means nobody except the person with the password can access the file. Write your password down and store it separately from the encrypted file.

Is there a file size limit?

The practical limit depends on your browser and device memory. Files up to about 500MB work on most modern devices. Very large files (1GB+) may cause browser slowness. For large files, consider a desktop tool like 7-Zip or VeraCrypt.

Encrypt Any File Online Free — AES-256, No Upload, No Signup

Last updated: March 8, 20268 min read By Jake MorrisonSecurity Tools

You have a file that should not be read by anyone except the person you give the password to. Tax documents, medical records, contracts, personal photos, financial data, client files, passwords databases — anything that would be a problem if the wrong person opened it.

Most people know they should encrypt sensitive files. Most people don't do it because the tools are confusing. Here's the simplest way to encrypt any file in about 10 seconds.

How to Encrypt a File (Step by Step)

Open the File Password Protector in any browser.
Drop your file into the encrypt zone. Any file type, any size up to ~500MB.
Enter a password. Make it strong — at least 12 characters, mix of letters, numbers, and symbols.
Click "Encrypt & Download." The tool creates an encrypted copy with a .enc extension.
Done. The .enc file is encrypted with AES-256-GCM. Without the password, it's unreadable.

How to Decrypt a File

Open the same tool.
Switch to the "Decrypt File" tab.
Drop the .enc file in.
Enter the same password used to encrypt.
Click "Decrypt & Download." The original file is restored.

Encrypt any file. AES-256, no upload, no account.

Encrypt a File Now →

Why "No Upload" Matters

Many online encryption tools upload your file to a server, encrypt it there, and send it back. That means:

Your unencrypted file passes through someone else's server
It might be logged, cached, or stored temporarily
The connection could be intercepted (even with HTTPS, the server itself sees the file)
You're trusting a third party with the exact thing you're trying to protect

A browser-based tool that runs locally avoids all of this. Your file stays on your device. The encryption happens in your browser's built-in cryptography engine. Nothing goes over the network. The tool itself doesn't even know what file you encrypted — it can't, because it never sees it.

What AES-256-GCM Actually Does

When you click "Encrypt," here's what happens inside the tool:

Key derivation: Your password is run through PBKDF2 with 100,000 iterations and a random salt. This turns a simple password into a 256-bit encryption key. The 100,000 iterations make brute-force password guessing extremely slow.
Encryption: Your file is encrypted using AES-256 in GCM mode. GCM (Galois/Counter Mode) provides both confidentiality (nobody can read the data) and integrity (any tampering is detected).
Unique per encryption: A random salt and random IV (initialization vector) are generated for each file. This means encrypting the same file with the same password twice produces two completely different encrypted outputs.
Output: The .enc file contains the salt, IV, encrypted filename, and encrypted file data. All packaged into a single downloadable file.

What You Can Encrypt

File Type	Works?	Notes
PDF documents	✓ Yes	Tax returns, contracts, medical records
Images (JPG, PNG)	✓ Yes	Personal photos, ID scans, receipts
Videos (MP4, MOV)	✓ Yes	Keep under ~500MB for browser performance
Spreadsheets (XLSX, CSV)	✓ Yes	Financial data, client lists, payroll
Word documents (DOCX)	✓ Yes	Contracts, legal documents, resumes
Archives (ZIP, RAR)	✓ Yes	Encrypt an already-zipped bundle
Text files (TXT, JSON)	✓ Yes	Config files, password lists, notes
Any other file	✓ Yes	The tool encrypts raw bytes — format does not matter

When to Encrypt Files

Before emailing sensitive documents

Email is not encrypted end-to-end by default. Your message and attachments pass through multiple servers in plain text. Encrypt the file first, attach the .enc file, and share the password through a different channel (text message, phone call). We cover this workflow in detail in our encrypt before emailing guide.

Before uploading to cloud storage

Google Drive, Dropbox, and iCloud encrypt files on their servers, but they hold the keys. A data breach or government request could expose your files. If you encrypt before uploading, even a compromised cloud account can't read your data.

On portable devices

USB drives, external hard drives, and SD cards get lost. An encrypted file on a lost USB is useless to the finder. An unencrypted file is a data breach.

For personal records

Tax returns, medical records, bank statements, ID scans, legal documents — anything you wouldn't want a stranger reading if your laptop was stolen or your cloud account was compromised.

Password Tips for File Encryption

Length matters more than complexity. "correct-horse-battery-staple" is stronger than "P@55w0rd" because it's longer. Aim for 12+ characters minimum.
Don't reuse passwords. If you use your email password to encrypt files, and your email is breached, your files are exposed too.
Store the password separately. Not in the same folder as the encrypted file. Use a password manager, a physical notebook, or a different device.
There is no recovery. If you forget the password, the file is gone. AES-256 has no backdoor, no reset, no master key. This is a feature, not a bug.

AES-256 encryption. Your browser. Your file stays on your device.

Encrypt Your File →

Jake Morrison Security & Systems Engineer

Jake has spent a decade on client-side security architecture. His conviction that files should never touch a third-party server is the foundation of WildandFree's zero-upload design.