maxant Steganography - Help
To merge your secret data (the "hidden" file) into your "input" image,
use the encryption form. The "Data to hide" is the
file that you wish to be hidden within the input image. It can be any file type
(text, image, sound, etc). As a rule of thumb you can store up to three quarters of a byte per pixel.
So roughly speaking, if an input image is 100 pixels wide by 100 pixels high,
you can store up to around 75 kB in it. Note however that it might be better, as well as harder to
decipher if you stored a larger file. A practical example is the second set of examples on the front
page of this site. The input image was 350x263 which gives up to 67 kB. We have actually managed to pack
a 72 kB PDF document into that. The output is the same resolution but is 222 kB, partly because it contains
the hidden data and partly because it is a PNG format image.
You must also supply a pass phrase (twice to ensure that you typed it correctly). It is recommended that the
pass phrase contain letters, numbers as well as symbols such as +"*ç%&/()=?. It is called a pass PHRASE
and not a pass word because we encourage you to use a phrase or sentence rather than a single word. The longer
the pass phrase, the harder it will be to crack your hidden data.
Once processed, the "output" image is shown on the screen. Informational messages are also displayed
above the image, for example:
Used 70% of the file, with a sparcity of 25.0%.
This message indicates that every 4th pixel (the 25%) was modified, and only 70% of the file was needed.
This is quite a good result. Crackers trying to decipher your message will not know how many of the pixels
were changed, and in this case they would have to stumble on the fact that it was every 4th. Every
processing result will be different, adding an extra layer of deciphering that a cracker needs to solve.
Even if the changed pixels are determined, the resulting data that can be extracted would appear
useless since it is encrypted to at least a
DES standard encryption. Without the
pass phrase, it is not possible to extract the hidden data, because internally even more enciphering is
done to the data. Exactly what, is a closely guarded kept secret to help ensure your data stays safe!
If the input image is too small to contain the hidden data, you will get an error as follows:
Failed: Input file was not long enough, only completed 26%.
Use a larger input image (more pixels), something around 70x70.
This indicates that your input image does not contain enough pixels to complete the encryption process.
Find a picture of at least the recommended size (or containing the same number of pixels as
the recommended size) and start the process again.
Once you successfully generate an output image, you can simply right click on it to save it:
Choose an appropriate file name and store it as a PNG (Portable Network Graphics) image:
This image format is easily read by most graphics viewers. It can be passed on to whomever you wish
to share your secret data with. All they need to decrypt it is the pass phrase that you used.
The weakest part of this entire process is your pass phrase. Ensure that you keep it safe at all times
and that it is not distributed with the output image! Saying that, due to our bespoke encryption algorithm,
any potential crackers would need to know about maxant in order to decrypt the message, although there is a
small chance that with the pass phrase they could do it without the website.
To extract your secret data (the "hidden" file) from the "output" image,
use the decryption form. The "Image containing the hidden data" is the
file that you have been given to decrypt. It is generally speaking always a PNG image file.
The pass phrase must be exactly the same one used during encryption.
Once decrypted, depending upon what the hidden data is, you will either see the hidden data on the screen
or get a link you can use to download it. In the case that it is not an image or text, you get such a link.
You have two options.
Option 1You can click on the link and the browser will attempt to show you the data or if it cannot
it will offer to save the data for you. If saving, you need to provide the file extension as given to you
on the page.
Option 2You can right click on the link and choose to save the data. Again, you need to then
provide the file extension as given to you on the page.
Note: The image is only stored temporarily on the server. If you click more than one time on the link,
it will not show you the data again. In such cases where you have problems similar to this, simply decrypt
again by refreshing the browser on the page where the link / image is shown (the decryption results page).