Steganography
Hide secret text inside an image with LSB steganography, optionally password protected, then extract it again - all in your browser. The exported PNG looks identical to the original; never re-save it as JPEG.
What is steganography?
Steganography is the art of hiding a message inside another file so that its very existence is invisible. Here your text is buried inside an ordinary photo through tiny changes to pixel colors - the picture looks exactly the same and nobody notices a message is there.
What is LSB and how does it work?
LSB means least significant bit, the very last bit of a binary value. Each color channel (red, green, blue) is stored with 8 bits, and the tool replaces only the final bit of each channel with a bit of your message. The maximum change to any color is 1 out of 255, which the eye cannot detect.
How much text fits in an image?
Capacity equals width x height x 3 / 8 bytes, because every pixel carries 3 hidden bits. A 1000 x 1000 image, for example, holds about 375 KB of text, minus a 9-byte header reserved first. The tool shows the available capacity and disables the hide button when your message exceeds it.
Why must the result be exported as PNG?
PNG stores pixels losslessly, so the hidden bits survive exactly. JPEG recompresses the image and destroys those bits, which ruins the message. That is why a warning appears for JPEG uploads: the download is always a PNG and must never be re-saved as JPEG.
What happens if the image is recompressed?
Any lossy re-save - converting to JPEG, or sharing through apps that re-encode photos (many messengers do) - overwrites the low bits and corrupts the message. Share the file exactly as downloaded, preferably as a file attachment rather than a displayed image.
What does the password do?
With a password the tool generates a byte stream that is XORed into your text and scatters the bit positions in an order driven by the password plus a random salt stored in the image. A wrong password yields only random-looking garbage, and a checksum detects the failure instead of showing nonsense.
Is this strong encryption?
No. The password masks and scatters the message, but this is steganography, not cryptographic security - someone who understands the method could detect that hidden data exists. For truly sensitive content, encrypt it with a dedicated tool first, then hide the encrypted text in the image.
Are my images or messages uploaded?
No. All processing happens locally in your browser through the Canvas API - no image, no text and no password is ever sent to a server, no account is needed and the page works offline once loaded.
How to Use Steganography
This steganography tool hides a secret text message inside an ordinary photo using LSB (least significant bit) embedding. The exported PNG looks and opens exactly like the original picture, but carries your message in the lowest bit of every red, green and blue value. Nobody can see the difference by looking at the image, and everything is processed locally in your browser.
- Open the Hide tab, then click the upload area or drag a PNG/JPG photo into it. The image is flattened onto a white background and shown in the preview.
- Type the secret message into the text box and optionally enter a password. The capacity line shows how many bytes the image can carry (width x height x 3 / 8) and how many your message needs, including a 9-byte header.
- Press Hide text in image. The message bits are written into the lowest bit of each color channel, scrambled with a password-driven stream if you set one.
- Press Download PNG and share the file as-is. Never re-save it as JPEG or send it through apps that recompress images - lossy compression overwrites the hidden bits.
- To read a message, open the Extract tab, upload the stego PNG, enter the same password if one was used, and press Extract text. A wrong password produces only garbage.
A 1000 x 1000 pixel image holds about 375 KB of text (minus the 9-byte header). Treat the result as covert, not as strong encryption: the password scatters and masks the message, but for truly sensitive data use dedicated encryption first.
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