Top Banner

Click here to load reader

of 27

About Steganography

Apr 24, 2015



FOR SEMINAR in B.Tech 3rd year

  • 1. SUBMITTED BY- MAYANK JAISWAL(0900410041) PAWAN KR. VERMA(0900410055) SUDHANSH GUPTA(0900410077)
  • 2. Outline What is Steganography ? Steganography History Watermarking and Cryptography Steganography vs. Cryptography Steganography vs. Watermarking Steganography Carrier Files Modern Steganography Techniques Basics of Modern Steganography Important Requirement for Steganographic System Uses for Steganography Steganography Tools Detection of Steganographic Content/Countermeasures Existing Steganographic Techniques Existing Attacks Conclusion Reference
  • 3. What is Steganography ? Steganography is of Greek origin and means concealed writing - from the Greek word steganos meaning covered and the Greek word graphie meaning writing Steganography is the process of hiding of a secret message within an ordinary message and extracting it at its destination. Steganography is a technique of hiding information in digital media. The art of detecting Steganography is referred to as Steganalysis.
  • 4. Figure-1
  • 5. Steganography - History Both Axis and Allied spies during World War II used such measures as invisible inks using milk, fruit juice or urine which darken when heated. Its also a very good Anti-forensics mechanism to mitigate the effectiveness of a forensics investigation In ancient Greece they used to select messenger & shave their head, they would then write a message on their head, once the message had been return the hair was allowed to grow back after the hair grew back the messenger was sent to deliver the message, the recipient would shave off the messengers hair to seethe secret message
  • 6. Watermarking and Cryptography There are two major branches of information hiding, Cryptography and Watermarking. Watermarking :- Communication in watermarking is the host signal, with the embedded data providing copyright protection. The existence of a watermark is often declared openly. Any attempt to remove or invalidate the embedded content renders the host useless. Cryptography :- Doesnt conceal the communication. Scrambles the data to prevent eavesdroppers understanding the content. Cryptography involves various methods and implementations. May be considered complementary and orthogonal (unrelated).
  • 7. Security level Figure-2
  • 8. Steganography vs. Cryptography Steganography and cryptography are closely related. Cryptography scrambles messages so it cant be understood. Steganography on the other hand, hide the message so there is no knowledge of the existence of the message. With cryptography, comparison is made between portions of the plaintext and portions of the cipher text. In steganography, comparisons may be made between the cover-media, the stego- media, and possible portions of the message. The end result in cryptography is the cipher text, while the end result in steganography is the stego-media. The message in steganography may or may not be encrypted. If it is encrypted, then a cryptanalysis technique is applied to extract the message.
  • 9. Steganography vs. Watermarking Digital watermarking can be a form of steganography, in which data is hidden in the message without the end user's knowledge.It is a technique which allows an individual to add hidden copyright notices or other verification messages to digital audio, video, or image signals and documents. Such a message is a group of bits describing information pertaining to the signal or to the author of the signal (name, place, etc.) The technique takes its name from watermarking of paper or money as a security measure. Figure-3
  • 10. Steganography Carrier Files bmp (bit map picture) jpeg (joint photographic experts group) gif (graphics interchange format) wav (waveform audio) mpeg(moving picture experts group) png(portable network graphic) Amongst others
  • 11. Modern Steganography Techniques 1. Masking and Filtering: Is where information is hidden inside of a image using digital watermarks that include information such as copyright, ownership, or licenses. 2. Algorithms and Transformations: This technique hides data in mathematical functions that are often used in compression algorithms. 3. Least Significant Bit Insertion: The most common and popular method of modern day steganography is to make use of the LSB of a pictures pixel information.
  • 12. Basics of Modern Steganography fE: steganographic function "embedding" fE-1: steganographic function "extracting" cover: cover data in which emb will be hidden emb: message to be hidden key: parameter of fE stego: cover data with the hidden message Figure-4
  • 13. Important Requirement for Steganographic System 1. Security of the hidden communication 2. Size of the payload 3. Robustness against malicious and unintentional attacks Figure-5
  • 14. Uses for Steganography Covert communications Privacy Espionage Terrorism Criminal activities Intellectual property protection Digital watermarks Digital signatures
  • 15. Steganography - Tools Steganos S-Tools (GIF, JPEG) StegHide (WAV, BMP) Invisible Secrets (JPEG) JPHide Camouflage Hiderman Many others
  • 16. Detection of Steganographic Content/Countermeasures The detection of steganographically encoded packages is called Steganalysis. Visual Analysis tries to reveal the presence of secret communication through inspection, either with the naked eye or with the assistance of a computer. Statistical (Algorithmic) Analysis reveals tiny alterations in an image's statistical behavior caused by steganographic embedding. The nominally universal methods developed to detect embedded stego-data are generally less effective than the steganalytic methods aimed at specific types of embedding.
  • 17. DIFFERENT KINDS OF STEGANOGRAPHY The four main categories of file formats that can be used for steganography are: I. Text II. Images III. Audio IV. Protocol
  • 18. Text steganography: Hiding information in text is the most important method of steganography. The method was to hide a secret message in every nth letter of every word of a text message. After booming of Internet and different type of digital file formats it has decreased in importance. Text stenography using digital files is not used very often because the text files have a very small amount of redundant data. Text steganography can be classified in three basic Categories:- Format-based Random Statistical generation and linguistic method.
  • 19. Figure-6
  • 20. Image steganography: Images are used as the popular cover objects for steganography. A message is embedded in a digital image through an embedding algorithm, using the secret key. The resulting stego image is send to the receiver. On the other side, it is processed by the extraction algorithm using the same key. During the transmission of stego image unauthenticated persons can only notice the transmission of an image but cant guess the existence of the hidden message. Figure-7
  • 21. Audio steganography: Audio stenography is masking, which exploits the