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Everything you need to know about Add Salt
Why 'Add Salt'?
In cryptography, 'salt' is random data added to a password before hashing to make it harder to crack. The same concept applies here—we add a unique layer of meaning to your image that transforms ordinary pixels into a vessel for your secret.
Just as salt protects a password, Add Salt protects your secret message within an image.
How It Works
1. Create a Salted Image
Upload any image and write your secret message. Add Salt creates a salted image with two recovery paths: the code is hidden inside the image, and a small color-block code is placed at the bottom as a compression-resistant fallback.
2. Share the Image
Send the salted image to your special someone through any channel—email, messaging apps, social media. The image looks completely ordinary.
3. They Discover the Secret
Your special someone uploads the image to Add Salt. We first try to read the hidden image data; if compression has damaged it, we can read the bottom color blocks to recover the code and reveal the secret.
How to Share a Salted Image
Salted images are designed to tolerate normal compression because the bottom color-block code can still recover the secret code. For best results, keep the bottom color blocks visible, clear, and uncut.
Avoid cropping the bottom strip, covering it with stickers or captions, heavy blur, strong filters, or very low-resolution screenshots. The original file is still best, but a compressed image often works if the color blocks remain readable.
Supported Formats
We support JPG, PNG, HEIC, and WebP images up to 10MB. Add Salt processes your upload into a shareable JPEG and adds both hidden image data and a bottom color-block recovery code. Keep the final image intact, especially the bottom strip.
Is It Secure?
Add Salt uses a dual-channel design: DCT-style image hiding for the image itself, plus a visible bottom color-block recovery code. This makes discovery much more resilient to common image compression than relying on hidden pixels alone.
This is still meant for personal, playful messages rather than critical security. Anyone who has the salted image and can access Add Salt may be able to reveal the message.