Posted at 11.15.2018
Steganography has been derived from Greek word "Stego" which means "Covered" and "Graphia" which means "writing". Steganography is an ancient approach of covert communication. The earliest form of Steganography has been reported by the China. The secret meaning was written in very fine silk or newspaper, and then it was rolled into a ball and covered with wax. The messenger would either swallow the ball or conceal it in his nether parts. Herodotus has brought up in one of his seminal works of record, Histories through the 400B. C about the traditions of hidden knowledge writing. In his writings he has brought up about the issues between Greece and Persia. A ruler named Histiaeus urged the Aristagoras of Miletus to revolt up against the Persian ruler. He used to tonsure the top of his most respected servants and tattooed the scalps with hidden knowledge concept and waited for the hair to develop. The servant used to travel between the edges without taking anything contentious easily. In the reception end his head would be tonsured again and the meaning will be conveyed. In the same way through the World Conflict II, the Germans invented the utilization of microdots. Image comprising great details were scaled down to the size of microdots. The German use of secret sharing is regarded as the recent development of Steganography. Another exemplory case of Steganography is during the Vietman Battle were the captured US armed force showed side gestures during a photo sessions to convey some armed forces secrets. The field of Steganography is unlimited and any sort of cover media can be used for carrying key text messages. Cover medias can be text, images (gray, binary, color), audio tracks, video etc. A good example is illustrated as follows.
Siva and Adam dined happily.
The following concept is not simply a plain text but it carries a secret meaning within it. By extracting every second notice from each expression we derive a magic formula message as follows.
Other ways of non complex Steganography is using lime and other citrus liquids to write key data. The communication will be imperceptible to the attention. When it is shown on the fire the writings will become perceptible.
Steganography is method of information covering. Steganography can be considered as an art as well as science for top secret communication.
The best way to explain the purpose of using Steganography is the Prisoner Problem. Now let us consider two prisoners Alice and Bob, and Wendy to be the warden. Now if Alice and Bob want to devise a plan for escaping then they got to communicate with each other. If Wendy is a passive warden then he won't interfere within communication but if he's a dynamic warden then he will interfere and remove the secret communication sent. Hence Alice and Bob got to communicate so that Wendy struggles to decipher there plan. This can be done by the strategy of Steganography.
Steganography is been used in order to enable secret communication. Additionally it is being used by terrorist for covert communication which is prospect of endangering our countrywide as well as world security. Despite the ill effect there are positive edges of Steganography. For example a shooter can store the aperture size, future referrals etc while taking a picture. Steganography has a broad software in medical imaging were the details of the patients are inserted within the medical image. In the same way Steganography can be used for different friendly applications. It is also used for copy right protection using it along with Watermarking.
The use of Steganography also has an important role in conditioning countrywide security. Steganography is thought as secret hiding. It can be regarded as secret sharing since messages can be shared secretly without having to be hacked or corrupted.
The other forms of data covering are cryptography and watermarking. Cryptography is a technique where the secret message is encrypted and submitted an unintelligent format. The basic difference between Steganography and cryptography is that Cryptography scrambles the data whereas Steganography just hides the data. Cryptography scrambles the trick data so that it looks gibberish to any unintended end user. The trick data to be communicated is a mixture of permutation and substitution and hence any unintended individual can't receive the message.
Steganography differs from Cryptography. Steganography rather hides the info whereas Cryptography encrypts the info. Steganography provides much more security when compared to cryptography since there is no potential for any unintended individual to know that a message is being dispatched whereas in Cryptography there will be a suspicion a message has been sent. Hence they are more susceptible to be hacked or suppressed.
Watermarking is normally used for authentication and copyrights coverage. Watermarking can be utilized for creating a image to ensure that it is recognizable. It can even be used to make a digital data file so that it is intended to be visible (visible watermarking) or noticeable to its creator (unseen marking). The main reason for watermarking is to avoid the illegal copying or state of ownership of digital media.
The common attribute between Steganography, Cryptography and Watermarking is that they transfer the trick information in such a way that only the recipient is able to decrypt the info. These techniques had been prevalent during the early times have been carried to the digital world. It has become nearly impossible to extract or detect the trick text messages. In digital domains Steganography and watermarking have a tie up and it is majorly used in digital images. These have other uses as well. Both cannot are present by themselves so therefore they require cover objects. Steganography takes a cover media to carry the secret information and watermarking takes a carrier thing which it is supposed to safeguard. These similarities create a web link within them and therefore some modifications may lead the transportation in one strategy to another. Anticipated the similarities present between these it is difficult to tell apart between your both but actually there's a remarkable difference between them. Cryptography encrypts data in two methods secure or unbreakable (e. g. One-time pad) systems and breakable (e. g. RSA) systems. Through both systems communication completed may all. But it is frustrating and frequently fruitless to split a code. The robustness of the code sits upon the down sides encountered while reversing the code in different permutations and combinations. Because of its robustness it is utilized for security purposes. For example Cryptography is used for online shopping, bank etc. The credit card amount, expiration etc and other essential information's are encrypted and delivered so an unintended user can't access the facts.
Steganography offers high carrier capacity keeping embedded message unseen and keeping the fidelity of the cover marketing. The efficiency of the Steganographic method is that you shouldn't know that a media file has been modified in order for embedding. If the malicious user has learned when there is some alteration the Steganographic method is defeated and less useful. The embedded communication is very delicate and hence if any modification is done to the stego image the whole secret communication is corrupted. The performance lies on the capability to fool an unintended individual. The layers of communication can be more than one covering. A secret note can be inserted with a digital image which can be embedded within another digital press or video recording clippings.
Watermarking is necessary for authentication and copyright coverage of digital data files. The embedded watermarking is necessary in an object to make it impossible to remove completely. When the inlayed watermarking is removed, then your marked object is either distorted or damaged making it inadequate for anyone. This is why why watermarking is better quality in comparison with the other image finalizing techniques, such as compression, cropping, rotation etc. hence even if handful of information is extracted by modification and tempering the rightful owner can still assert ownership. In the event the owners name is embedded in the digital image and the particular image then the original information is tampered and demolished. Unlike Steganography, it is satisfactory for everyone one to see the watermark inserted in it like the invisible ones.
Cryptography can be used as a paisano of the other two data covering techniques. Data is encrypted in both techniques to be able to improve the randomness of the Steganography to all the statistics-based attacks also to protect the hidden data in watermarking. Commonly it is a practice to first encrypt the data and then use any one of the inlayed techniques.
The need for watermarking can be mentioned as follows. Assume Rs 100 expenses is launched in Dec 2009 then watermarking is necessary in order to prevent illegal copies. When the costs is shown in light a small image will appear within the top image. The watermarking is actually a part of the large paper and is also obvious on both sides. Hence it becomes quite difficult to produce a paper with such features. In addition to these features some little writings which are invisible to the individual eyes are present in the newspaper.
A banker getting the necessary gadgets (magnifying glass) can tell the difference between the original charge and the false bill. Steganography makes its play here. The very small printing done on the costs represents Steganography. It really is implemented in order to accomplish high security. The small printing done in the paper cannot be copied since any commercial printer is incapable to print out such a fine and thin print leading to dark spots. They are why Steganography is used for high security.
Cryptography is actually carried out in the invoice. A serial amount is been published in the costs which might contain information about the location and particular date of expenses is imprinted or any other confidential information. The initial serial number for each bill can be utilized for tracking purposes. Using Steganography, Cryptography and Watermarking it becomes impossible to reproduce Rs100 charge. It must be considered that three will vary and have different operation.
Any digital mass media can be used as a cover marketing. The cover advertising can be a content material, image (color, gray), sound or video recording etc. Cover multimedia is required to be able to cover up and carry the info. Usually digital images are essential in order to hide secret messages. The trick message is hidden within the digital image. Following the message is inlayed within the cover media
An innocuous image consisting of surroundings, people and other objects are the nominees for cover press. The availability of natural images is not a problem due to the affordable price of digital camera models nowadays. Natural images will be the best individuals for cover image given that they have higher quality providing overall flexibility and other necessary need.
Images are preferred because the cover multimedia is selected depending upon the way the human aesthetic system works. The gray image includes pixels with power value from 0 to 255. The eye cannot differentiate between a pixel intensity of 244 and 245. It'll appear both the pixel intensities to be same. Also natural image s is made up of lots of sound and hence there may be tons of pixel value level difference especially in the corners. This variation in the pixel strength is known as randomness and can be exploited to embed the info without providing any suspicion to eye. The human visible system won't be able to differentiate between your image before modulation and the image after modulation.
The hidden knowledge data is embedded within the cover image. The causing image is called a stego-image. The stego-image can look to be the same as the original image. The eye cannot usually separate between your stego-image and the original image except there is a significant change between your images. If so the Steganographic method employed is inadequate. Hence there are specific Stego-system conditions which we have to follow while performing a Stegagraphic implementation. These are stated the following.
The three basic requirements of Steganography are robustness, capacity and imperceptibility. Each one of these requirements should be satisfied for having an effective Steganographic method.