Encrypt a File with a Password Online — AES-256, No Upload | MultiTools

What Does It Mean to Encrypt a File?

Encrypting a file scrambles its contents using a password so that nobody can read it without that password. The original document, image, or archive is transformed into meaningless data; only someone who knows the password can turn it back into the real thing. This tool encrypts files directly in your browser using AES-256, the same strength of encryption trusted by banks and governments, with a password that you choose.

The key idea is control. When you email a sensitive document, store it in cloud storage, or hand someone a USB stick, you lose control of where that file ends up. If it is encrypted, it does not matter who intercepts or copies it — without the password it is unreadable. Because everything here happens on your device, your file and your password are never uploaded, so you are not trading one privacy risk for another just to protect your data.

Why Use This File Encryptor?

• Nothing is uploaded. Your file and password stay on your device from start to finish, which makes this safe for confidential and personal files.
• Strong, modern encryption. Files are protected with AES-256-GCM, which also detects tampering, so you know a decrypted file is exactly what was encrypted.
• It verifies its own work. Right after encrypting, the tool decrypts the result in memory to confirm it can be opened again before you download it.
• Works on any file type. Documents, photos, spreadsheets, archives — anything can be encrypted and later restored with its original name.
• No account, no cost, no install.

Common Use Cases

• Emailing sensitive documents — encrypt a contract, tax form, or medical record before attaching it, and share the password through a separate channel.
• Cloud and backup storage — keep an encrypted copy in cloud storage so the provider, or anyone who breaches it, cannot read your files.
• Carrying files on a USB drive — protect data in case the drive is lost or stolen.
• Sharing credentials or keys — wrap a file of secrets in a password before sending it to a teammate.
• Personal privacy — lock away financial records, IDs, or private photos on a shared computer.

How to Use This Tool

1. Choose Encrypt or Decrypt — pick Encrypt to lock a file, or Decrypt to open one you locked earlier.
2. Add your file — drag and drop it onto the page or click to browse. It stays on your device.
3. Enter a password — choose a strong password and confirm it. A strength meter helps you pick a good one.
4. Run the tool — click Encrypt to produce a locked file, or Decrypt to restore the original.
5. Download the result — save the encrypted or decrypted file, ready to store or share.

Frequently Asked Questions

Is my file uploaded anywhere?

No. Encryption and decryption happen entirely in your browser. Your file and your password never leave your device, which is why this is safe for confidential material.

What happens if I forget the password?

The file cannot be recovered. The password is the only key, and it is never stored or sent anywhere, so there is no reset option and no back door — by anyone, including us. Keep your password somewhere safe.

How strong is the encryption?

Files are protected with AES-256-GCM. Your password is stretched into a 256-bit key using a slow, salted process that makes guessing attacks far harder. A long, unique password gives you the best protection.

Can the person I send the file to open it?

Yes, if they use this same tool and know the password. The encrypted file uses a format that this tool reads. Share the password separately from the file for safety.

Does it work for large files?

It works for everyday documents, images, and archives. Very large files are limited by your device's available memory, since all the work happens locally in the browser.