Steganography is the method of hiding a secret message in or on something that is public.
It’s first recorded use was in 1499 in a book by Johannes Trithemius that talked about cryptology and magic.
Steganography saw use in both world wars, when female spies would send hidden messages in knittings they made. The spies would put knots in at certain points and these knots would be used to communicate a message. To someone who didn’t know what they were looking for, the knitting would look just like another other knitting.
In the digital age, IT professionals have taken to use steganography with digital files and pictures.
Unlike with previous forms of of steganography, with digital steganography its impossible to decode the hidden message with the human eye. Specialized software is needed to properly decode the and view the hidden data of the image.
For instance, we have placed a hidden message in the picture of the cute puppy at the top of the page.
To do this we used a tool called “SilentEye”
SilentEye is a free tool used for encoding and decoding hidden messages in various file formats such as pictures and audio files.
Once we installed SilentEye from the project’s website we can use it to open the JPG file we wish to hide our message in.
From here we just click the encode button in the bottom right and we will be greeted with a window that allows us to put in the secret message!
We will also need to input a passphrase to decode the message.
If we also wish to hide an entire file in the image, we can do that here as well.
With the passphrase set and message written, we can hit the encode button and the program will generate a new image with our hidden message!
We can now send this image to whoever we need communicate with and they will be able to extract the message.
To get the message from the image, just open the image in SilentEye and click the "Decode" button in the bottom left.
A window will popup and all we have to do is enter the correct passphrase and then click decode in the bottom right.
If the passphrase is correct, we will get the secret message!
Now you can try it yourself!
As a test, you can try extracting the hidden message from the image of the puppy!
Click here to download the picture.
And use the passphrase of "firestorm"