Transcript: "Boss said that we should blow up the bridge at midnight." Physical examples The art and science of writing hidden messages Terrorists hide data in public images (2000s) Watermarking היפרגונגטס Evgeny Nemzer A Trojan horse inside of the organization's network can modify outgoing packets to create a covert channel. Outside, an agent is listening and receiving all of the information. Digital examples A hidden tattoo on the head of a greek slave (499 BC) Invisible ink (French resistance during WWII) "Doll Woman" (Spying for the Japs in WWII) A whole ASCII letter per 3 pixels! Network Steganography Single image pixel : 11010011 10110001 00111101 Modified image pixel: 11010011 10110001 10111101
Transcript: Digital Steganography Steganography and Cryptography are closely related The difference is in their goals... Cryptography: although encypted and unreadable, the existence of data is not hidden Steganography: no knowledge of the existence of the data Steganography and Cryptography can be used together to produce better protection Outline Hiding a Message inside Audio or Videos Files Hiding a Message inside Text Outline Image “painted” with the watermark: “Invisible Man” © 1997, Neil F. Johnson Hiding a Message inside Text Hiding a Message inside Images Most popular technique Hiding a Message inside Audio and Video Files source: wikipedia.org Network Security and Steganography Hiding a Message inside Images Pelin Gul Sankar Das randoM capitalosis is a rarE disEase ofTen contrAcTed by careless inTernet users. tHis sad illnEss causes the aFfected peRsON To randomly capitalize letters in a bOdy oF texT. please do not confuse this disease witH a blatant attEmpt aT steganogRAPhy. Reveals: MEET AT THE FRONT OF THE TRAP What is Steganography? Uses of Steganography Its Relation to Cryptography Digital Watermarking Network Security and Steganography Types of Steganography Detecting Steganography: Steganalysis Future of Steganography History of Steganography Digital watermarking hides data in a file, and the act of hiding data makes it a form or steganography The key difference is their goals... Steganography: hiding information Watermarking: extending the file with extra information Steganographic information must never be apparent to a viewer unaware of its presence. Steganography & Cryptography Businesses: Digital Watermarking Individuals Uses of Steganography The most important use of steganographic techniques will probably lie in the field of digital watermarking Might become limited under laws - governments claimed that criminals use steganography to communicate ...the End Hiding a Message inside Text Types of Digital Steganography Confidentiality: any unauthorized person does not know that sensitive data exists Survivability: verifying that the data does not get destroyed in the transmission No detection: cannot be easily found out that the data is hidden in a given file Visibility: people cannot see any visible changes to the file in which the data is hidden Steganography in Ancient Greece Ancient Rome - 1499, Steganographia, the first book about steganography World War II Germany - microdots Modern Steganography - 1985, with the development of personal computers Digital Steganography – with internet (e.g.digital watermarking) Digital Steganography Digital Steganogaphy & Watermarking Digital Watermarking The most popular medium! Least-significant bit (LSB) modifications 24-bit vs. 8-bit images Tools to implement LSB: EzStego and S-Tools Masking and Filtering Algorithms and Transformations Used primarily for identification Embedding a unique piece of information within a medium (typically an image) without noticeably altering the medium Almost impossible to remove without seriously degrading an image What is Steganography? Uses of Steganography Its Relation to Cryptography Digital Watermarking Network Security and Steganography Types of Steganography Detecting Steganography: Steganalysis Future of Steganography What is Steganography? Detecting and decoding the hidden data within a given medium Even if secret content is not revealed, modifying the cover medium changes the medium’s statistical properties Distributed Dictionary Attack Steganalysis Pelin Gul Sankar Das Advantages Human limitations – 20.000 Hz. Large amount of data that can be hidden inside Hard to recognize because of because of the continuous flow of information (moving stream of images and sound) Hiding an Image within an Image Digital Watermarking Partially effective Future of Steganography
Transcript: THE ALGORITHM 3-LSB THE ALGORITHM Types of Steganography Why only the least bit? Greeks and their 'art' Extracting information Range Table • Hiding information in image. • Embed the secret information in bit pixels i.e 8 bit or 24 bit. Video steganography is a branch of data hiding, which is a technique that embeds message into cover contents. Steganography in video PIXEL VALUE DIFFERENCING Extraction Phase: Step-1: Find the difference value df '= | px'+1 - px' | from two consecutive pixels in the stego-image. The decimal value can be found as, dec= df' – Lb & finally represent the value of ‘dec’ in binary. Step-2: Repeat Step-1 until complete secret data has been found. What's the so different about it? INTRODUCTION OPTIMAL LSB CONCLUSION 95-89 = 6 Capacity Security Invisibility Tamper Resistance Imperceptibility One of the newly formed signals is considered optimal which is nearest to the original pixel value. TECHNIQUES IN IMAGE STEGANOGRAPHY where P and Q represent image size, P(x,y) is original pixel value and P'(x,y) is pixel value of stego image Text steganography is a mechanism of hiding secret text message inside another text as a covering message Embedding phase Let ‘b’ is a block of two non-overlapping pixels such as px and px+1 of a grey cover image. A difference value df = |px - px+1| can be found. The number of secret data (s) are to be embedded in the consecutive pixel will be decided by floor value, s=log2(Ubi − Lbi). Convert the secret data (s) to binary & let, ‘dec’ be its corresponding decimal value. Find a new difference value df' = Lb + dec. df & df' should be in same range in the range table. Let px' & px'+1 be the new pixel values derived from the equations in the figure shown. Text steganography Important factors in steganography LEAST SIGNIFICANT BIT METHOD 95-63=32 ! SPATIAL DOMAIN METHODS Divides a grey-scale image into two areas: Edge and smooth area Payload is defined by the difference between two consecutive pixels. Makes use of a range table used to determine payload bits. Embedding information 1) LSB (Least Significant bit) 2) PVD (Pixel value differencing) Three main important factors should be considered in any successful steganography system: • Imperceptibility • robustness • embedding capacity Audio stenography can conceal the secret message in the audio file with the help of its digital representation. Steganography in audio: To explain further; let's consider: Py (Original pixel value) s (secret data) Px (Pixel value of stego-image) Pm = Px+2^k and Pn = Px-2^k (where k is length of s) Po (Optimal pixel value) STEGANOGRAPHY Steganography in image:
Transcript: what is Steganography Early Steganography the differenece between steganography and cryptography is that cryptography is a technique used to hide the message from the reader while steganography is the technique used to prevent the message from being read at all. it is meant to camouflage the meaning of the message in something inanimate or something that would otherwise not be viewed unless you knew what you were looking for. in 1883 Auguste Kerchoffs wrote two novels which stated 6 principles for military cyphers. the system must me practically, if not mathematically indecipherable it must not be required to be secret; it must be able to fall in the hands of the enemy without any inconvenience. it must be communicable and retainable without the help of written notes. it must be applicable to telegraphic correspondence it must be portable. the system must be easy to use. most of these rules are no longer applicable with the rise of technology but the second principle is still considered a very important aspect of Steganography. this was the work of a monk name johannes thrithemius his method was to hide his messages in the second letters of every second word this message reveals the word prymus apex. before the introduction of technology steganography was alot more basic and just plain clever. in early chinese civilization it was common to write messages on silk, encase them in wax then stick them "in" the messengers. in greek legend there are stories of men having their head shaved then they would be tattooed with a secret message on the scalp and then their hair would grow back leaving the message out of view unless one knew it was there. Steganography Steganography vs. Cryptography padiel aporsy mesarpon omeuas peludyn malpreaxo The art or practice of concealing a hidden message within another message the word Steganography is greek and translates to " covered writing" Steganography has been apart of human society for an undetermined amount of time. evidence of its use is seen in Egyptian art and in many other civilizations. Kerchoffs' Principle
Transcript: 1. To hide an image inside another, the image which will be hidden needs to have at most the same size of the image which will hide it. To reveal an image the same code is required with the additional knowledge of knowing how many bits were used to hide the image. Presented by: Soha Khalid Thank you for listening. 5. Finally, we convert the new binary value to a decimal value: How it works 2. We must create two loops to go through all rows and columns (actually each pixel) from the images. Unmerging an image Advantages of steganography over cryptography Steganography 4. We merge the most significant bits from the image 1 with the most significant bits from the image 2 using the __merge_rgb method Steganography works by replacing bits of useless or unused data in regular computer files (such as graphics, sound, text, HTML, or even floppy disks ) with bits of different, invisible information. This hidden information can be plain text, cipher text, or even images. - Messages do not attract attention to themselves. Plainly visible encrypted messages— no matter how unbreakable—will arouse suspicion and may in themselves be incriminating in countries where encryption is illegal. Therefore, whereas cryptography protects the contents of a message, steganography can be said to protect both messages and communicating parties. - This method featured security, capacity, and robustness, the three needed aspects of steganography that makes it useful in hidden exchange of information through text documents and establishing secret communication. - Important files carrying confidential information can be in the server in and encrypted form no intruder can get any useful information from the original file during transmit. - With the use of Steganography Corporation government and law enforcement agencies can communicate secretly. As you can see in the image above, we lost some image quality in the process, but this does not interfere with image comprehension. What is steganography? Hiding a secret message within an ordinary message and the extraction of it at its destination. Steganography takes cryptography a step farther by hiding an encrypted message so that no one suspects it exists. 3. So, we get the RGB from the image 1 and image 2 as binary values: We can use the __int_to_bin method to convert a decimal value to a binary value:
Transcript: Each bit is then replaced by LSB of each Image byte Introduction History Steganography v/s Cryptograpy Types of Steganography Steps Involved in Steganography Steganography Techniques Digital Images Lossy and Lossless Compression Advantages Applications Conclusions Types of Steganography Image Bits after Image Bits before Least Significant Bit Insertion Lossy and Lossless Compression Cryptography hides the contents of a secret message from a malicious people, whereas Steganography even conceals the existence of the message In cryptography, the structure of a message is scrambled to make it meaningless and unintelligible unless the decryption key is available Steganography does not alter the structure of the secret message, but hides it inside a cover-image so it cannot be seen. Digital Images It is used in the way of hiding not the Information but the password to reach that Information. Messages do not attract attention to themselves i.e difficult to detect. Only receiver can detect. The proposed technique uses LSB to hide data from a pre defined position agreed between two parties. Same position is only used once to enhance security. Can be applied differently in digital image, audio & video file. Detecting Steganography Detecting Steganography By digital Images we presume to deal with bits that is 0’s and 1’s. Digital Images having 24-bit depth color images are selected using RGB color model. The idea is to hide text in image with the conditions that the image quality is retained along with the size of the image. 24-bit BMP is preferred over 24-bit JPEG because it is lossless compression. :¬) Greeks used it writing message on some material and later covering it with wax, tattooing messages on shaven head, later growing hair to cover it up. In World War II invisible inks were used to write messages in between the lines of normal text message . Currently, cryptography and steganography are used to hide and send the secret data. File compression software looks for redundancies, and eliminates those redundancies in order to reduce the size of the file. Lossy compression reduces a file by permanently eliminating certain information. When the file is uncompressed, only a part of the original information is still there. With lossless compression, every single bit of data that was originally in the file remains after the file is uncompressed. All of the information is completely rest Cryptography History Advantages Take T of binary value 11100110. To store these 8 bits of character T, we will require 8 pixels. Steganography Injection: Injection is quite a simple method which simply involves directly injecting the secret information into the carrier file. Substitution: Replacement of the least significant bits of information that determine the meaningful content of the original file with new data in a way that causes the least amount of distortion. Generation: The generation technique, unlike injection and substitution, requires only a covert file, as it is used to create the overt file. Applications Steps involved in Steganography Introduction Any Queries....... ? ? ? By Pranav Kumar Logeshwaran Pranesh Padmanabhan Abimanyu LSB Implementation Detecting By histogram technique : Steganography Techniques Thank You..!! The most common and popular method of modern day steganography. Overall image distortion is kept to a minimum while the message is spaced out over the pixels in the images. This technique works best when the image file is larger then the message file and if the image is grayscale. Messages are encoded in LSB of every byte in a image. Value of each pixel change slightly. Grey scale palettes due to least pronounced shades are recommended. Greek Words: STEGANOS – “Covered” GRAPHIE – “Writing” Advance security is not maintained by the password protection but it is gained by hiding the existence of the data, which can only be done by Steganography. Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message. This can be achieve by concealing the existence of information within seemingly harmless carriers or cover Carrier: text, image, video, audio, etc. Steganography v/s Cryptography Example : Insert a word TEXT - T = 01100010 - E = 01101111 - X = 01101101 - T = 01100010 Steganography Example Steganography In Text/Documents Steganography In Images Steganography In Audio Steganography In Video The art of detecting Steganography is referred to as Steganalysis. Using different tools like sendsecret, Steganography 8.1 , Stegdetect, Hiderman etc. Steganalysis does not deal with trying to decrypt the hidden information inside of a file, just discovering it. It is mainly done with comparing the encrypted file with the original copy. Conclusion Why LSB? Cryptography Seminar Confidential communication and secret data storing Protection of data alteration Used in modern printers Protect copyrights, to maintain
Transcript: Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message. Watermarking steganalysis Tools History of Steganography Steganalysis Credentials leakage may occur and it leads to the unauthorized access of data. https://en.wikipedia.org/wiki/Steganography www.garykessler.net/library/fsc_stego.html searchsecurity.techtarget.com › Emerging threats › Network security "Steganography and classification of image steganography techniques" Computing for Sustainable Global Development (INDIACom), 2014 International Conference Disadvantages Protects copyright owners of digital documents by hiding a signature in the information in a way that even a modified part of the document conserves the signature. Greek Words: STEGANOS –- “Covered” , GRAPHIA -– “Writing” Saddamhusain Hadimani 01FM15ECS030 Advantages Difficult to detect and Only receiver can detect. It can be done faster with large no. of softwares. Provides better security for sharing data in LAN,MAN & WAN. Stegdetect stegsecret Stegexpose (LSB) Stego suite Applications INtroduction It can be used by intelligence agencies for sending their secret data. Steganography is the practice of hiding a file, message, image, or video within another file, message, image, or video. Lossy Lossless Steganography Media Database systems The confidentiality of information is maintained by the algorithms, and if the algorithms are known then this technique is of no use. Digital watermarks may be used to verify the authenticity or integrity of the carrier signal or to show the identity of its owners. References Block Diagram Thank You Confidential communication and secret data storing Protection of data alteration Access control system for digital content distribution Combined Crypto- Steganography
Transcript: Steganography Because you didn't even realize the message was there. Steganography. Is that like a Stegosaurus? Blog Steganography for each RGB value: Image Steganography Chaffing and Winnowing Blog Steganography Steganophony Physical Steganography Digital Steganography Printed Steganography Text Steganography Categories of Steganography Invented by Ron Rivest (of RSA) Requires secure message authentication code. (Charles does not need to know this.) Allows Alice to deny responsibility for encrpytion. Mimic Functions Sources Digital Steganography http://en.wikipedia.org/wiki/Steganography http://en.wikipedia.org/wiki/Chaffing_and_winnowing http://en.wikipedia.org/wiki/Mimic_function http://en.wikipedia.org/wiki/Stegasaurus http://people.csail.mit.edu/rivest/chaffing-980701.txt Image Steganography E for each pixel in the pictureToHide: for each pixel in the pictureToHideIn: -Wikipedia Conceals one message in another, or one piece of data in another. Can only be broken if someone's looking for it and knows how it works. A form of network steganography. Conceals a message in corrupted or delayed packets that would normally be ignored by a VOIP (voice-over-IP) connection. Optional: Encrypting the message. Using a secret-sharing scheme. The Premise: The Internets has a lot of orphaned blogs. There are a lot of orphaned blogs in the blogosphere. The word steganography is of Greek origin and means "concealed writing" from the Greek words steganos meaning "covered or protected", and graphein meaning "to write". How It Breaks The Method: Post your message in pieces on blogs in the order listed in the key. Steganographized The name Stegosaurus means "roof lizard" (sometimes put as "covered lizard", but in the sense that a roof covers a building), and is derived from the Greek stegos- ("roof") and σαῦροςsauros ("lizard") Hidden It's easy if you know it's happening. Just keep a copy of the image and look for versions with different values. T Chaffing and Winnowing Original How It Works Another Example from Wikipedia: Kind of. D Steganophony Extracted The Key: A list of orphaned blogs. replace the two least significant bits of the pictureToHideIn with the two most significant bits of the pictureToHide -Wikipedia http://www.spammimic.com/ Why Steganography? p(t,X) is the probability of some substring t occurring in file X. A mimic function f, recodes X so that p(t,f(X)) approximates p(t,Y), where Y is another file. H
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