It is used to embed and extract secret messages in images. It supports all the general formats of images like .png, .jpg etc.
$ sudo apt install steghide
To embed a secret message into an image
$ steghide embed -cf image.jpg -ef secret_message.txt Enter passphrase : ******** Re-Enter passphrase : ******** embedding "secret_message.txt" in "image.jpg"... done
To extract the secret message from the image
For any help with the commands type
$ steghide extract -sf image.jpg Enter passphrase : ******** wrote extracted data to "secret_message.txt".
It is important to note that the password may not always be a plain text sentence. Sometimes it may be hashed. Some examples of hashes include MD5, sha1 etc. We all know that there is no specific way to reverse the hashes. But, there are websites which store hashes of certain commonly used strings.
$ steghide --help
For more information about the tool,
$ man steghide