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JustTools

Image Steganography Tool

Hide text or a small file inside an ordinary-looking picture, lock it with AES-256 encryption, and let only the person with the password read it. Everything happens in your browser.

Runs in your browser Free · no sign-up

At a glance

  • Hides a message or a small file in the lowest bit of the colour values of an image’s pixels — a change of at most 1 in 255 that the eye can’t see.
  • With a password, the message is encrypted with AES-256-GCM (key from PBKDF2-SHA-256, 600,000 rounds) before it’s hidden, so it can’t be read or altered without the password.
  • Any photo works as the cover (JPG, PNG, WebP, HEIC); the result is saved as a PNG, because lossy formats would destroy the hidden bits.
  • Shows how much the image can hold — a 1,000 × 1,000 image holds about 370 KB — and checks the saved file reads back correctly.
  • Messages are compressed first, so long text takes less room. Hindi, emoji and any language work.
  • Runs entirely in your browser: images, messages and passwords are never uploaded.

Step by step

How to hide a message in an image

  1. 1

    Choose a cover image

    In Hide a message, drop any photo. Larger images can hold more.

  2. 2

    Write the message

    Type your text, or switch to A small file and choose one.

  3. 3

    Add a password

    Recommended: without it, anyone using this tool can read the message.

  4. 4

    Download and send

    Click Hide and download PNG, then send the PNG as a file or document — not as a photo.

Features

Everything you need, nothing you don’t

Invisible

The picture looks exactly the same. Only the tiniest bit of each colour value changes.

Password protected

AES-256 encryption means that even someone who knows there’s a message can’t read it without the password.

Text or files

Hide a note, a list of passwords, a key, or a small PDF or ZIP inside a photo.

Verified

After saving, the tool reads the message back from the file to make sure it will work for the recipient.

Reveal in one step

Drop the PNG in Reveal mode and enter the password — the message or file appears.

Private

No server ever sees your image, message or password.

Sending the image without losing the message

How you send itHidden message
Email attachment, Google Drive, Dropbox, USBKept
WhatsApp or Telegram “Document” / “File”Kept
WhatsApp, Instagram or Facebook as a photoDestroyed (the image is re-compressed)
Screenshot of the imageDestroyed
Converting to JPG or resizingDestroyed

How it works

Each pixel has red, green and blue values from 0 to 255. The tool writes the message, bit by bit, into the lowest bit of those values — changing a colour from, say, 200 to 201. That is far below what the eye can notice, so the image looks untouched. A short header marks where the message starts and how long it is.

Steganography hides that a message exists; encryption protects what it says. With a password, you get both. Note that specialised analysis software can often detect that an image contains hidden data, even if it can’t read it — so always use a password for anything sensitive.

FAQ

Frequently asked questions

Can anyone see that the image has a hidden message?

Not by looking at it. Forensic tools can sometimes detect that the pixels were altered, which is why a password matters: detected or not, the message can’t be read without it.

Why is the output a PNG?

PNG is lossless, so every bit is saved exactly. JPG and WebP photos are compressed in a way that changes pixel values slightly — enough to wipe out a hidden message.

How much can I hide?

About 3 bits per pixel: roughly 370 KB in a 1,000 × 1,000 image, or 1.1 MB in a photo reduced to 2,000 × 1,500. Text is compressed first, so a page of text needs only a few kilobytes.

I forgot the password. Can the message be recovered?

No. The encryption has no back door, and JustTools never sees your password, so it can’t be reset.

Can it read messages hidden with other steganography tools?

No. Each tool uses its own format. Reveal mode reads messages hidden with this tool.

Is steganography legal?

Yes, hiding your own messages in your own images is legal in India and most countries. Using it to commit a crime is not.

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