Steganography refers to the concealment of a secret message within an ordinary message. At the destination, the information is retrieved using a similar method. In essence, steganography is analogous to advanced cryptography since it an encrypted message is hidden in a way that it raises no suspicion. Ideally, any entity scanning such concealed data will definitely fail to point out if it contains encrypted data. In other words, information is passed to the intended entity without raising suspicion or suggesting its existence. This versatile and effective method of hiding data has gained popularity after the 9/11 terrorist attacks as a process that could be used by subversives, terrorist and others to transmit data or information in ways that are extremely difficult to detect.
Stenography is also defined as the art of hiding messages. It is more advanced than cryptography because it not only provides privacy, but also provides secrecy. Privacy is a feature presented by credit cards in online transactions. When credit cards are used online, their owners conceal the number from the public. In this end, cryptography finds use, and the card transmits encrypted data that can only be decrypted by the web application handling the transaction. In spite of the fact that, the secret code can complex, hackers can establish that the information was sent. In simple terms, under secrecy, the send protects the sent information by eliminating the suspicion. In fact, the idea is that no one should know that the information is sent. One of the outstanding features of stenography is that a secret message is hidden in the media which is sent. The redundant information serves as a distraction and could take any format.
In the present-day digital steganography, standard techniques are used to encrypt data at the initial stages, and then integrate into redundant data using a special algorithm. The redundant data can be an image or text file usually provided but not necessary. In other words, the encrypted information in steganography does not attract attention.
Stenography can be used for legal or illegal purposes depending on the user and the reasons behind the application. Firstly, the message, usually plaintext, is encrypted using traditional methods to produce a ciphertext. Then, a redundant covertext is altered in some way to carry the ciphertext. This results in a steganogram. In legitimate processes, the technique can be used to enforce intellectual property like copyrights by using watermarks in images. On the other hand, one of the most general despicable reasons includes hiding and transmitting information for illegal purposes. As a fact, terrorist organization such as Al-Qaeda among others are flagged for using this method to obscure information in redundant images uploaded on websites. In the networking field, the technique can be used to hide messages in Voice-over-IP (VOIP) as well as in the transmission of steganogram within Wireless Local Area Networks (WLAN).
Preventing steganography techniques or methods used to store and transmit illegal information is problematic because the information can be hidden in plain sight, thus culprits can easily get away with it. In fact, if it is done correctly, data or information can be concealed in any document, image or other pieces of information and never be suspected. Despite the fact that we cannot certainly confirm the extent of application of this process in criminal circles or illegal activities, it is probably acceptable to point out that it is in utilization by terrorists, criminals and other evil folks for numerous kinds of mischief. For entities on the good side, they can use security policies and code of honor to prevent the misuse of the technology.
In the Information and Technology realm, every measure has a countermeasure; thus steganography is not exceptional. In this context, the countermeasure is referred to as steganalysis. Steganalysis in a technique and process of detecting suspect piece of data, determine whether the data is obscured within the piece of data, and recover the hidden data. Superficially, Steganalysis sounds like cryptanalysis. However, the processes are not the same. In cryptanalysis, it is obvious that data is encrypted. We only need to have a look at the piece of data to establish whether it is encrypted or not. In contrast, the presence of hidden data is only suspected, and not confirmed by observation.
There are a number of tools that can be used to perform stenography. These tools are both online and downloadable. In the same context, there are several steganography tools used to carry out detection of data that has been hidden using this process. Some of the widespread tools used on some common types of media include Hiding Glyph, Vecna, F5, TrueCrypt, Steganos Privacy Suite and the Further obfuscation. Some of the free online tools include:
1. OpenPuff 4.00 http://embeddedsw.net/OpenPuff_Steganography_Home.html
2. Invisible Secrets http://www.invisiblesecrets.com
3. PGPn123 http://www.stegoarchive.com
Steganography is an ancient but incredibly effective and versatile method for hiding or obscuring information that is usually in plain sight. In spite of the fact that there are a number of methods for detecting obscured data, they cannot be relied upon entirely because none of them is 100 percent effective. Therefore, any efforts to detect and stop it must integrate vigilance and technology to constrain the effectiveness of the process.