steganography.js is a JavaScript library used to encode secret messages inside images and to decode them again.

Behind the scenes steganography.js uses an algorithm to convert the given message into appropriate binary data which then will be hidden in the alpha channel of the given cover image. A HTML5 canvas element is then used to process the data and the image. To decode a message from a given image, a similiar algorithm is applied on the imagedata.

The use of the library is very simple. You just have to add the .js-file to your website and by now you can make use of the global object steganography or short steg and the two provided functions encode and decode.

• encode takes a message as String and a image as Image, HTMLImageElement or String representing the data-URL of the cover image. Returns the data-URL of the image with the encoded message inside.
• decode takes a image as Image, HTMLImageElement or String representing the data-URL of the image and returns the message which was found in the image.

If you have any questions, contact me.
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