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Something lies beneath

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  1. 1. By: PAVNINDERPAL KAUR Uni. RN: 1269169 M.Tech (C.S.E.) L.L.R.I.E.T. , Moga
  2. 2.  Introduction  History  Basic Model Of Steganography  Steganography Technique  Why  steganography works Requirements that must be satisfied Applications of  Attacks  Steganography to Steganography References
  3. 3.  Steganography is of Greek origin where Greek words steganos meaning "covered or protected" graphei meaning "writing " Hence steganography means concealed writing [3].  Steganography is the art and science of embedding secret messages in cover message in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message.
  4. 4. Tattooing message on slaves head Writing messages on wood underlying wax tablets PERSHING SAILS FROM NY JUNE 1 Use of invisible inks Use of null ciphers
  5. 5. Secret Message Secret Message Cover Message EMBEDDING PROCESS Stego Object EXTRACTION PROCESS Cover Message SECRET MESSAGE is the information to be hidden in suitable media. COVER MESSAGE is the carrier of secret information such as image, audio, video etc. EMBEDDING ALGORITHM is the way or the idea that usually used to embed the secret information in the cover message. STEGO OBJECT is the cover message with secret message hidden in it [5].
  7. 7. Inputs of Embedding Algorithm Secret Message Cover Image 1 Cover Image 2 Secret Key Steganographic Algorithm Data Hiding Stego Object Data Extraction Secret Key Inputs of Extraction Algorithm Secret Message
  8. 8. In this method instead of hiding data in LSB of RGB components, data is hidden as shown in following example: Let the data to be hidden is word 'ABC'. Find the ASCII code of every character to be hidden. ASCII code of A is 65 and its corresponding binary is 01000001 ASCII code of B is 66 and its corresponding binary is 01000010 ASCII code of C is 67 and its corresponding binary is 01000011
  9. 9. EMBEDDING METHOD Let the RGB component of first pixel: RED 1 0 1 1 0 GREEN 0 0 1 0 1 0 0 1 BLUE 1 0 1 0 1 0 0 1 1 0 1 1 0 1 Red component is replaced by ASCII code of A in binary i.e. 01000001 : RED 0 1 0 0 0 GREEN 0 0 1 0 1 0 0 1 BLUE 1 0 1 0 1 0 Similarly, Green component of second pixel is replaced by ASCII code of B and Blue Component of third pixel is replaced by ASCII code of C 1 1
  10. 10. Inputs: - Text file, cover image 1, cover image 2 and secret key. Output: - Stego image. Begin 1. Select text file, convert into binary and calculate number of bits 2. Select cover image 1 for hiding purpose find the number of pixels, split it into RGB components 3. If bits are compatible with the image resolution, then start sub iteration 1, else start sub iteration 2 4. Provide security key 5. Select cover image 2 to hide distorted stego image END
  11. 11. SUB ITERATION 1 Replace red component of the first pixel with first character Replace green component of the second pixel with second character. Replace blue component of the third pixel with third character And repeat iterations until pixels get exhaust Stop sub iteration 1 SUB ITERATION 2 Replace necessary bits as in immediate component of each pixel Store the information about bits embedded in a binary address file And repeat iterations until pixels get exhaust Stop sub iteration2
  12. 12. Text File Convert into binary & cal. no. of bits If no. of bits=Resolution Find number of pixels in image If no. of bits ≠ Resolution Replace red comp. of 1st pixel with 1st character Repeat until pixels exhaust Replace necessary bits in pixels Replace green comp. of 2nd pixel with 2nd character Store info. about bits embedded in binary address file Replace blue comp. of 3rd pixel with 3rd character Secret Key Provide secret key Cover Image 1 Cover Image 2 Hide distorted image Repeat until pixels exhaust Stego Object
  13. 13. Input: - Stego image and secret key. Output: - Secret text file. Begin 1. Browse the stego image. 2. Choose the folder in which you want to extract the hidden text file. 3. Provide necessary security key. 4. Convert the binary file into human readable form. End
  14. 14.  Human Visual System (HVS) – Insensitivity to gradual changes in shade Insensitive to high frequencies and blue region of visible spectrum  Human Audio System (HAS) – Sensitive to additive random noise Inability to perceive absolute phase
  15. 15. The following is a list of main requirements that steganography techniques must satisfy [4]: a) The integrity of the hidden information after it has been embedded inside the stego object must be correct. b) The stego object must remain unchanged or almost unchanged to the naked eye. c) In watermarking, changes in the stego object must have no effect on the watermark. d) Finally, we always assume that the attacker knows that there is hidden information inside the stego object.
  16. 16.  Used by intelligence agencies.  Used by military forces to send secret messages.  Used in modern printers.  Used in digital watermarking.  Used by terrorists.  Used for corporate espionage to send out trade secrets.
  17. 17.  Additive Noise,  Filtering  Cropping  Compression  Rotation and Scaling  Statistical Averaging  Multiple Watermarking Depending on these types of attacks steganography may be classified as robust or fragile [2][4].
  18. 18. [1] Vipul Sharma, Sunny Kumar, “ A New Approach to Hide Text in Images Using Steganography”, IJARCSSE, Volume 3, Issue 4, ISSN: 2277 128X, April 2013. [2] James C. Judge, “Steganography: Past, Present, Future”, SANS Institute 2001. [3] Ross J. Anderson, Fabien A.P. Petitcolas, “On The Limits of Steganography”, IEEE Journal of Selected Areas in Communications, 16(4):474-481, ISSN 0733-8716, May 1998. [4] Ananthi S, Anjanadevi A “Reversible Image Data Hiding Using Predictive Coding Technique Based on Steganograpic Scheme”, IOSR Journal of Engineering (IOSRJEN) ISSN: 2250-3021 Volume 2, Issue 7(July 2012).
  19. 19. [5] Shashikala Channalli, Ajay Jadhav, “Steganography An Art of Hiding Data”, International Journal on Computer Science and Engineering Vol.1(3), 2009. [6] Emad T. Khalaf, Norrozila Sulaiman,"A Robust Data Hiding Technique based on LSB Matching", World Academy of Science, Engineering and Technology 58, 2011. [7] Atallah M. Al-Shatnawi, "A New Method in Image Steganography with Improved Image Quality",Applied Mathematical Sciences, Vol. 6, 2012.