The Types And Techniques Of Steganography Computer Science Essay

The Types And Techniques Of Steganography Computer Science EssayThis schedule focus on an unfamiliar field of study in IT sector i.e. Steganography. This document coers various concepts in Steganography, A legal brief hi apologue of Steganography and introducing few types of techniques available today in Steganography. It also coers other topics c are security in Steganography, expeditious messaging, MMS Steganography related training. This document closes with a summery and proper solution .The initial footages of Steganography were by the Hellenic historian Herodotus in hischronicles cheatn as Histories and date back to around 440 BC. Herodotus save two stories of Steganographic techniques during this cartridge holder in Greece. The first stated that King Darius of Susa s stick disclosed the head of one of his prisoners and wrote a riddle heart and soul on his scalp. When the prisoners hair grew back, he was sent to the Kings son in law Aristogoras in Miletus un detect ed. The second story also came from Herodotus, which claims that a soldier named Demeratus needed to send a subject to Sparta that Xerxes intended to invade Greece. tail then, the writing medium was text edition written on wax-c everywhereed launch aras. Demeratus removed the wax from the tablet, wrote the enigma nitty-gritty on the underlying wood, re subventioned the tablet with wax to make it appear as a blank tablet and netly sent the document without being detected. Romans utilise invisible inks, which were found on natural substances much(prenominal) as fruit juices and milk. This was accomplished by heating the inscrutable text, thus revealing its surfeits.Invisible inks have become much more advanced and argon still in limited use today. During the fifteenth and 16th centuries, many writers including Johannes Trithemius (author of Steganographia) and Gaspari Schotti (author or Steganographica) wrote on Steganagraphic techniques much(prenominal) as mark techni ques for text, invisible inks, and incorporating hidden messages in music. Between 1883 and 1907, further development screwing be attri only ifed to the publications of Auguste Kerckhoff (author of Cryptographic Militaire) and Charles Briquet (author of Les Filigranes). These books were mostly about Cryptography, and both sight be attributed to the foundation of both(prenominal) Steganographic outlines and more signifi posteriortly to watermarking techniques.During the times of WWI (World contend 1) and WWII (World War 11), signifi houset advances in Steganography excessivelyk place.Concepts such as null ciphers (taking the 3rd letter from each word in a harmless message to create a hidden message, etc), word picture substitution and microdot (taking entropy such as pictures and reducing it to the size of a large period on a piece of paper) were introduced and embraced as great steganographic techniques.In the recent digital world of today, namely 1992 to present, Steganog raphy is being apply exclusively over the world on reckoner clays. Many tools and technologies have been created that take advantage of old steganographic techniques such as null ciphers, tag in understands, auditory sensation, exposure and microdot. With the research this topic is directly getting a roundabout of great applications for Steganography in the near future.HOW STEGANOGRAPHY WORKSSteganography replaces unneeded or un utilise consequences in regular electronic computer files (Graphics, sound, text) with bits of different and invisible education. Hidden teaching can be any other regular computer file or encrypted info.Steganography differs from cryptography in a focus that it masks the existence of the message where cryptography industrial plant to mask the confine of the message.Steganography or sotimes used in conjunction with encryption. An encrypted file may still handle information development steganography, so even if the encrypted file is deciph ered,the hidden information is non seen..TYPES OF STEGANOGRAPHYThere are different bureaus to hide the message in a nonher, well known are Least meaningful bytes and Injection.When a file or an image is created there are few bytes in the file or image which are not necessary or least important. These type of bytes can be replaced with a message without damaging or replacing the original message, by which the enigmaticale message is hidden in the file or image.Another way is a message can be directly injected into a file or image. nevertheless in this way the size of the file would be increasing wherefore depending on the secrete messageSTEGANOGRAPHY IN IMAGEDigital images are the most widely used height objects for steganography. Due to the availability of various file formats for various applications the algorithm used for these formats differs accordingly.An image is parade of bytes (know as pixels for images) containing different light intensities in different areas of t he image. When dealing with digital images for use with Steganography, 8-bit and 24-bit per pixel image files are typical. Both have advantages and disadvantages 8-bit images are a great format to use because of their relatively grim size. The drawback is that only 256 doable intensitys can be used which can be a authorization problem during encryption. Usually a gray scale color palette is used when dealing with 8-bit images such as (.GIF) because its gradual change in color would be vexeder to detect after the image has been encoded with the secret message. 24-bit images offer much more flexibility when used for Steganography. The large sum ups of colour (over 16 million) that can be used go well beyond the human visual system (HVS), which makes it very hard to detect once a secret message, has been encoded.Large amount of selective information can be encoded in to 24-bit images as it is compared to 8-bit images. The drawback of 24-bit digital images is their size which is very high and this makes them suspicious our internet due to their heavy size when compared to 8-bit images. Depending on the type of message and type of the image different algorithms are used.Few types in Steganography in ImagesLeast significant bit insertion showing and filteringRedundant Pattern EncodingEncrypt and dissipateAlgorithms and transfigureationsLeast significant bit insertionLeast Significant Bit (LSB) insertion is most widely known algorithm for image steganography ,it involves the modification of LSB layer of image. In this technique,the message is stored in the LSB of the pixels which could be considered as random haphazardness.Thus, neutering them does not have any obvious effect to the image.Masking and filteringMasking and filtering techniques employ better with 24 bit and grey scale images. They hide info in a way kindred to watermarks on actual paper and are sometimes used as digital watermarks. Masking the images changes the images. To ensure that chang es cannot be detected make the changes in multiple small proportions. Compared to LSB masking is more stalwart and masked images passes cropping, compression and some image processing. Masking techniques found information in significant areas so that the hidden message is more integral to the make out image than just privateness it in the noise level. This makes it more suitable than LSB with, for instance, lossy JPEG images.Redundant Pattern EncodingRedundant pattern encoding is to some extent similar to spread spectrum technique. In this technique, the message is scattered through out the image based on algorithm. This technique makes the image ineffective for cropping and rotation. Multiple smaller images with redundancy increase the chance of regain even when the stegano-image is manipulated.Encrypt and ScatterEncrypt and Scatter techniques hides the message as white noise and blanched Noise Storm is an example which uses employs spread spectrum and frequency hopping. Prev ious window size and data production line are used to generate a random number.And with in this random number ,on all the cardinal channelizes message is scattered through out the message.Each channel rotates,swaps and interlaces with every other channel. Single channel represents one bit and as a result there are many unaffected bits in each channel. In this technique it is very complex to draw out the actual message from stegano-image. This technique is more secure compared to LSB as it needs both algorithm and hear to decode the bit message from stegano-image. Some users prefer this methos for its security as it needs both algorithm and make out despite the stegano image. This rule like LSB lets image degradation in terms of image processing, and compression.Algorithms and transformationsLSB modification technique for images does hold commodity if any kind of compression is through on the resultant stego-image e.g. JPEG, GIF. JPEG images use the discrete cosine transform t o achieve compression. DCT is a lossy compression transform because the cosine values cannot be calculated exactly, and perennial calculations using limited precision numbers introduce rounding errors into the final result. Variances between original data values and restored data values depend on the method used to calculate DCTSTEGANOGRAPHY IN soundImplanting secrete message into an audio is the most challenging technique in Steganography. This is because the human auditory system (HAS) has such a vibrant range that it can listen over. To put this in perspective, the (HAS) recognize over a range of power greater than one million to one and a range of frequencies greater than one thousand to one making it extremely hard to add or remove data from the original data structure. The only weakness in the (HAS) comes at trying to differentiate sounds (loud sounds drown out quiet sounds) and this is what essential be exploited to encode secret messages in audio without being detected. to a lower place are the lists of methods which are commonly used for audio Steganography.LSB codingParity codingPhase codingSpread spectrumEcho hidingLSB codingUsing the least-significant bit is thinkable for audio, as modifications usually would not create recognizable changes to the sounds. Another method takes advantage of human limitations. It is realizable to encode messages using frequencies that are indistinct to the human ear. Using frequencies above 20.000Hz, messages can be hidden interior sound files and can not be detected by human checks.Parity codingInstead of breaking a indication down into individual samples, the parity coding method breaks a signal down into order regions of samples and encodes each bit from the secret message in a sample regions parity bit. If the parity bit of a selected region does not match the secret bit to be encoded, the process flips the LSB of one of the samples in the region. Thus, the sender has more of a choice in encoding the secret bit, and the signal can be changed in a more unobtrusive fashion.Phase codingPhase coding attends to the disadvantages of the noise bring forth methods of audio Steganography. Phase coding uses the situation that the phase helpings of sound are not as audible to the human ear as noise is. Rather than introducing perturbations, this technique encodes the message bits as phase shifts in the phase spectrum of a digital signal, attaining an indistinct encoding in terms of signal-to-perceived noise ratio.Spread spectrumIn the context of audio Steganography, the basic spread spectrum (SS) method attempts to spread secret information across the audio signals frequency spectrum as much as possible. This is comparable to a system using an implementation of the LSB coding that randomly spreads the message bits over the entire audio file. However, unlike LSB coding, the SS method spreads the secret message over the sound files frequency spectrum, using a code that is independent of the ac tual signal. As a result, the final signal occupies a bandwidth in excess of what is actually required for broadcast.Echo hidingIn let loose hiding, information is implanted in a sound file by introducing an echo into the separate signal. like the spread spectrum method, it too provides advantages in that it allows for a high data transmission rate and provides superior aptitude when compared to the noise inducing methods. If only one echo was produced from the original signal, only one bit of information could be encoded. Therefore, the original signal is broken down into blocks before the encoding process begins. Once the encoding process is completed, the blocks are concatenated back together to create the final signal.STEGANOGRAPHY IN VIDEOIn video steganography, a video file would be embedded with supplementary data to hide secret messages. In the process, an intermediate signal which is a function of hidden message data and data of content signal would be generated. field of study data (video file) is then combined with this intermediate signal to result encoding. The supplementary data can include copy control data which can be brains by consumer electronic fraud and used to disable copying.The intermediate signal may also contain a pseudo irresponsible key data so as to hide encoding and decode needs corresponding key to unneededct hidden information from encoded content. In some implementations regulation data is embedded in the content signal with auxiliary data. This regulation data consists of known properties enabling its identification in the embedded content signal. This encoding is robust against scaling, resampling and other forms of content degradation, so that the supplementary data can be detected from the content which might have been degraded.There are different approaches for video steganography apart from the above mentioned. well-nigh widely known are listed and discussed below.Least Significant Bit InsertionThis is the most si mple and public approach for all types of steganography. In this method the digital video file is considered as separate frames and changes the displayed image of each video frame. LSB of 1 byte in the image is used to store the secret information. Effecting changes are too small to be recognized by human eye. This method enhances the capacity of the hidden message but compromises the security requirements such as data virtue.Real time video steganographyThis kind of steganography involves hiding information on the output image on the device. This method considers each frame shown at any second irrespective of whether it is image text .The image is then divided into blocks. If pixel colors of the blocks are similar then changes color characteristics of number of these pixels to some extent. By labeling each frame with a sequence number it would even be easy to identify missing parts of information. To extract the information, the displayed image should be recorded first and relev ant program is used then.STEGANOGRAPHY IN DOCUMENTSteganography in documents just focuses on altering some of its characteristics. They can either be characteristics of text or even text formatting. Below are few ship canal listed and discussed to implement the same.Since everyone can read, encoding text in neutral sentences is doubtfully effective. But taking the first letter of each word of the previous sentence, one can see that it is possible and not very difficult. Hiding information in plain text can be done in many different ways. One way is by simple adding white space and tabs to the ends of the lines of the document .The last technique was successfully used in practice and even after a text has been printed and copied on paper for ten times, the secret message could still be retrieved.Another possible way of storing a secret inside a text is using a in public available cover source, a book or a newspaper, and using a code which consists for example of a cabal of a page n umber, a line number and a character number. This way, no information stored inside the cover source leads to the hidden message. Discovering it depends exclusively on gaining knowledge of the secret key.Setting background color and font color is one of the mainly used staganographic approach. This method is focused for Microsoft word documents. Choose predefined colors and set font and background colors of invisible characters such as space, tab or the fishing rig return characters. R,G,B values are 8 bits means we have allowed range of 0 to 255.Most of the viewers would not feel interested about color values of these invisible characters hence 3 bytes of information is considerably hidden in each occurrence of space,tab or carriage return.This approach needs no extra information to hide required bits.SECURITY IN STEGANOGRAPHYPURE cay STEGANOGRAPHYPure Steganography is a Steganography system that doesnt require prior exchange of some secret information before sending message the refore, no information is required to start the communication process the security of the system thus depends entirely on its secrecy .The pure Steganography can be defined as the quadruple (C, M, D, and E) whereC the set of possible covers.M the set of secret massage with C M.E C-MC the embedding function.D CM of the extraction function with the property that D (E(c,m))=m for all m M and c C.Cover (C)Message (M)Embedding (E)Extracting (D)Strgo-ObjectMessage(M)In most applications, pure Steganography is preferred, since no stego-key must be overlap between the communication partners, although a pure Steganography protocols dont provide any security if an attacker knows the embedding method nonpublic KEY STEGANOGRAPHYA Private Key Steganography system is similar to a symmetric cipher, where the sender chooses a cover and embeds the secret message into the cover using a secret key. If the Private Key used in the embedding process is known to the receiver, he can reverse the proce ss and extract the secret message.Anyone who doesnt know the Private Key should not be able to obtain evidence of the encoded information. The Private Key Steganography can be defined as the quintuple (C, M, K, DK, and EK) whereC the set of possible covers.M the set of secret message.K the set of secret keys.Ek C-M-KC With the property that DK (EK(c,m,k),k)=m for all m M, c C and k KKEYKEYStrgo-ObjectCover (C)Embedding (E)Message (M)Extracting (D)Message (M)PUBLIC KEY STEGANOGRAPHY national key Steganography does not depend on the swapping of a confidential key. It necessitates two keys, one of them private (secret) and the other public the public key is stored in a public database, whereas the public key is used in the embedding process. The Private Key is used to reconstruct the secret message One way to underframe a public key Steganography system is to use a public key crypto system. The sender and the receiver can exchange public keys of some public key cryptography algori thm before imprisonment. Public key Steganography utilizes the fact that the decoding function in a Steganography system can be employ to any cover, whether or not it already contains a secret message. The public key Steganography relies on the fact that encrypted information is random enough to hide in plain sight. The sender encrypts the information with the receivers public key to obtain a random-looking massage and embeds it in a channel known to the receiver, thereby replacing some of the natural arbitrariness with which every communication process is accompanied. Assume that both the cryptographic algorithms and the embedding functions are publicly known. The receiver who cannot decide a priori if secret information is transmitted in a specific cover suspect the arrival of message and simply try to extract and decrypt it using his private key. If the cover actually contained information, the decryption information is the senders messageOTHER TYPESMOBILE MESSAGING STEGANOGRAPH YMobile Messaging service of process enables mobile users to send and receive messages containing image, audio and video. These messages are exchanged ultimately through a component known as Mobile Switching Center.MMS messages have several benefits like communicating even when the waiter is busy, exchanging messages while making calls, sending offline messages. They also provide services like eCommerce. As there is hypothesis of disclosure of confidential and personal information between various systems, information security has got immense importance. MMS Steganography provides confidentiality and integrity with subtle unremovability.Users can profit from concealed channels in order to send and receive hidden messages and keys.Multimedia objects may contain hidden information embedded to them using steganography techniques.The steganography technique used must satisfy followingReliability of secreted information after it has been embedded inside the content should be correct.Co ntent object should remain intact or almost unchanged to the human eyes.There can be mainly two types of steganography techniques possible for MMS objects.Fragile steganography comprises of implanting information into a file which is destroyed if the file is modified. mental picture Technique Works over video files. Combinations of sound and image techniques are used to implement this as whole. The scope of adding lots of data is much greater.Sound Technique Works over audio files like Mp3 files. Encode data as binary to sound like noise and can be identify by receiver with correct key. Data being added is in narrow bandwidth compared to the medium.Robust techniques aim to embed information into a file which cannot easily be destroyed.Image Hiding Works over images. rental Significant BitLeast significant bits of each pixel in one image are used to hide the most significant bits of another. Simple and easy way of information hiding.Direct romaine TransformTransformed DCT coefficien ts would be neutered. Image would be made robust by scattering the hiding information evenly.Wavelet TransformDividing whole image into small wavelets and then hide the information. Coefficients of wavelets are altered with tolerable noise.Text Technique Works over documents.Just by changing some of the characteristics of the content information can be embedded. Alterations would not be visible to user.As MMS Steganography becomes more widely used now there must be a clear definition of validity. This definition helps to prevent detection and remotion of embedded data. Below are the few properties a good technique should holdQuality of media should not perceptibly degrade after embedding secret data.Secret data should be imperceptible with out secret knowledge, typically the key.If several data are there, they should not hamper with each other.Secret data should abide which dont degrade the perceived quality of work.MMS STEGANOGRAPHY RELATED WORKAs MMS carries multi formatted dat a such as Text, Audio, pictorial matter and images, it has got more chances of sending secret messages and can implement various methodologies in order to keep the message safe and secret. Currently this study is all about Text and Video based Steganography.An MMS capable mobile with inbuilt cameras and customized applications has high importance in terms of steganography creation and extractionCapacityEfficiency bear on timeResource time consumptionAdvantageText technique slightto a greater extentLessLessEasy and simple to implementVideo techniqueMoreMoreMoreMoreHolds lot of information compared to text techniqueTable -1- comparison between Text and Video steganography Techniques suitable SOLUTIONMMS Messages can hold any of video, audio, image and text encapsulated with in Synchronized Multimedia integration Language (SMIL) .The recommended steganography deals with three major parts of MMS which can provide us with maximum capacity possible and not compromising main aim which is total security. The most important issues in steganography are secrecy, payload, robustness and speed. Below steps describes proposed steganography working modelFirst part of the process hides stegno key in SMIL using white space algorithm.Then Least Significant Bit algorithm is used to hide the secret message in video.Rest of the information would be hidden inside text of the MMS using abridgment algorithm.Ratio of information hiding in video part to text part is 61 hence I bit stored in text corresponds to 6 bits stored in 3gp video.High security can be granted with reasonable processing speed and without affecting the performance of mobile.2.10 CHAPTER SUMMERYThis document is all about available Steganography techniques and methodologies. It has listed down the various methodologies and their uses. Along with these, it has also included about the MMS Steganography importance and ways to do that.