Image steganography and cryptography

Image steganography and cryptography

• 1.
  STEGANOGRAPHY “The Art OfHiding Data” Department of Computer Science & Engg. Gandhi Institute for Technological Advancement(GITA), Bhubaneswar.
• 2.
  OVERVIEW • What isSteganography? • History • Steganography vs Cryptography • Types of Steganography • Basic Steganography Model • Techniques for using Image Steganography • LSB Algorithm • Steganography And Cryptography • Application • Conclusion 2
• 3.
  • The wordsteganography is of Greek origin and means "concealed writing" from the Greek words steganos meaning "covered or protected", and graphein meaning "writing". • Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message. • The main objective of Steganography is mainly concerned with the protection of contents of the hidden information. What is Steganography 3
• 4.
  • The firstrecorded uses of steganography can be traced back to 440 BC where wax tablets were used to write message. • Ancient Chinese wrote messages on fine silk, which was then crunched into a tiny ball and covered in wax. • During Second World War a technique was developed to shrink photographically a page of text into a dot less than one millimeter in diameter History Of Steganography 4
• 5.
  Steganography VS Cryptography STEGANOGRAPHYCRYPTOGRAPHY Steganography prevents discovery of the very existence of communication Encryption prevents an unauthorized party from discovering the contents of a communication Technology still being develop for certain formats Most of algorithm known by all Once detected message is known Strong current algorithm are resistant to attacks ,larger expensive computing power is required for cracking Steganography does not alter the structure of the secret message Cryptography alter the structure of the secret message 5
• 6.
  • Text Steganography: Text steganography can be achieved by altering the text formatting, or by altering certain characteristics of textual elements • Image Steganography : Images are used as the message carriers. Images are the most popular cover objects used for steganography. • Audio Steganography : In audio steganography, secret message is embedded into digitized audio signal which result slight altering of binary sequence of the corresponding audio file. Types Of Steganography 6
• 7.
  Basic Steganography Model Secret message Cover Stegosystem encoder Key Stegosystem decoder Stegoobject Secret Message Communication Channel Stego Object 7
• 8.
  • By usingLSB(Least Significant Bit algorithm) • Masking and Filtering • Algorithms and Transformation Techniques for using Image Steganography 8
• 9.
  • Least significantbit (LSB) insertion is a common, simple approach to embedding information in a cover image. • The least significant bit of some or all of the bytes inside an image is changed to a bit of the secret message. • When using a 24-bit image, a bit of each of the red, green and blue colour components can be used, since they are each represented by a byte. • In its simplest form, LSB makes use of BMP images, since they use lossless compression. LSB Algorithm 9
• 10.
  What Images aremade up of?:- Images are made up of lots of little dots called pixels. Each pixel is represented as 3 bytes – one for Red, one for Green and one for Blue. 11111000 11001001 00000011 • The difference between two colors that differ by one bit in either one red, green or blue value is impossible detect for a human eye. • This means we can overwrite the last bit in a byte without affecting the colors it appears to be. Cont… 10
• 11.
  • Example: We canuse images to hide things if we replace the last bit of every color’s byte with a bit from the message. Message A-01000001 Image with 3 pixels Pixel 1: 11111000 11001001 00000011 Pixel 2: 11111000 11001001 00000011 Pixel 3: 11111000 11001001 00000011 Cont… 11
• 12.
  Now we hideour message in the image. Message: 01000001 Pixel 1: 11111000 11001001 00000010 Pixel 2: 11111000 11001000 00000010 Pixel 3: 11111000 11001001 00000011 Cont… 12
• 13.
  Steganography And Cryptography PlainText Encryption Cipher Text Cover Image Stego Images Cipher TextDecryptionPlain Text 13
• 14.
  • Transport HighlyPrivate Documents between International Governments. • Copyright protection: A secret copyright notice or watermark can be embedded inside an image to identify it as intellectual property. • Feature tagging: An article, illustration, or poster and other brief explanation elements can be embedded inside an image. • Usage in modern printers. Application 14
• 15.
  • Security isan important issue while transferring the data using internet because any unauthorized individual can hack the data and make it useless or obtain information un- intended to him. • Hiding a message with steganography methods reduces the chance of a message being detected. • In and of itself, steganography is not a good solution to secrecy, but neither is simple substitution and short block permutation for encryption. But if these methods are combined, we have much stronger encryption routines. Conclusion 15
• 16.
  THANK YOU