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  • 1. 1 Secret Communication Through Audio For Defense Applications INTERNAL GUIDE MRS.M.MADHURI LATHA PRESENTED BY, J.Prathima 09251A0482 S.Spandana 09251A04B0 E.Nikhila 09251AO475 B.Asritha 09251A04C0
  • 2. 2 The basic mechanisms for security of data are:
  • 3. 3 •Cryptography was concerned solely with message confidentiality (i.e., encryption) •Cryptography is secret writing. Anybody can see the message, but nobody else can read it. • Usually, this is because its letters have been re- arranged, or replaced by different letters, according to some scheme that only the sender and receiver know. • Only those who possess a secret key can decrypt the message into plain text
  • 5. 5 STEGANOGRAPHY: Steganography comes from the Greek Word which means covered or secret message. STEGAN-O-GRAPHY COVERED + WRITING
  • 6. 6 • Steganography is a means of storing information in such a way that it hides private information and even the existence of the information within the other medium. • The goal of Steganography is “to hide messages inside other harmless messages, in a way that does not allow any enemy to detect that there is a second secret message present”.
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  • 8. 8 STEGANOGRAPHY CRYPTOGRAPHY Unknown message passing Known message passing Little known technology Common technology Technology still being developed for certain formats Most of algorithms known by all Steaganography does not alter the structure of the secret message. Cryptography alters the structure of secret message.
  • 9. 9 A Steganography system Message file Cover fileCover file Steg file (with hidden data) Steg file (with hidden data) Message file Steganography ToolSteganography Tool Steganography ToolSteganography Tool Hiding messages Extracting messages
  • 10. 10 BASIC TYPESBASIC TYPES OFOF STEGOSYSTEMSSTEGOSYSTEMS Three basic types of stego systems 1. Secret-key stego systems 2. Public-key stego systems 3. Pure stego systems 10 .
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  • 13. 13 oSteganography in Text oSteganography in Images oSteganography in Audio Image steganography
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  • 21. 21 Variation in choosing LSBVariation in choosing LSB
  • 22. 22 TERMINOLOGY USED…TERMINOLOGY USED… • Cover : The data that is visible to the world. • Embedded: The data to be hidden (not visible to the world). • Stego: The data contains both cover and embedded data. • The data may be audio or video or image. • In case of audio data the cover is also termed as host signal, where as in case of image data the cover is termed as container. • The process of hiding the data is known as embedding.
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  • 24. 24 WAV • WAV files are short for waveform audio files. • Microsoft and IBM first introduced the WAV file. • The Audio data after the sampling is done is stored in computer as a .wav file. • The average song has a large file size from 35 and 50 megabytes. • Most popular Audio Format. • Don’t lose any quality in recording.
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  • 26. 26 Stego Audio Embedding Process LSB of the Data Part Alternate Samples of LSB Data Audio Input Separate Header and Data Secret Text BLOCK DIAGRAM EMBEDDING:
  • 27. 27 Convert Binary to ASCII Extraction Process Store LSB of Data Part Left Shift of Previous bit Stego Audio Separate Header and Data Extracted Text Extracting:
  • 28. 28 LETERSWITH ASCII VALUESAND CORRESPONDING BINARY VALUES Letter ASCII Value Corresponding Binary Value A 065 01000001 U 117 01110101 D 100 01100100 I 105 01101001 O 111 01101111 LETTERS WITHASCIIVALUES AND CORRESPONDING BINARY VALUES
  • 29. 29 ALGORITHM (FOR EMBEDDING OF DATA): ALGORITHM (FOR EMBEDDING OF DATA): • Leave the header section of the audio file untouched. • Start from a suitable position of the data bytes. (For the experiment purpose the present start byte was the 51st byte). Edit the least significant bit with the data that have to be embedded. • Take every alternate sample and change the least significant bit to embed the whole message.
  • 30. 30 SAMPLES OF AUDIO FILE WITH BINARY VALUES BEFORE ANDSAMPLES OF AUDIO FILE WITH BINARY VALUES BEFORE AND AFTER EMBEDDINGAFTER EMBEDDING Sample No. Binary values of corresponding sample Binary value to be embedded Binary values after modification 51 01110100 0 01110100 53 01011110 1 01011111 55 10001011 0 10001010 57 01111011 0 01111010 59 10100010 0 10100010 61 00110010 0 00110010 63 11101110 0 11101110 65 01011100 1 01011101
  • 31. 31 • Leave first 50 bytes. • Start from the 51st byte and store the least significant bit in a queue. • Check every alternate sample and store the least significant bit in the previous queue with a left shift of the previous bit. • Convert the binary values to decimal to get the ASCII values of the secret message. • From the ASCII find the secret message. ALGORITHM (FOR EXTRACTING OF DATA): ALGORITHM (FOR EXTRACTING OF DATA):
  • 32. 32 EXRACTION OF DATA FROM AUDIO FILE Sample No. Binary values with embedded secret data Bits that are stored in the queue 51 01110100 0 53 01011111 01 55 10001010 010 57 01111010 0100 59 10100010 01000 61 00110010 010000 63 11101110 0100000 65 01011101 01000001
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  • 35. 35 • Modern Printers: o HP and Xerox brand colour laser printers o Tiny yellow dots are added to each page. o The dots are barely visible and contain encoded printer serial numbers as well as date and time stamps.
  • 36. 36 CorPorAte WorLd: In business world audio data hiding can be used to hide a secret chemical formula or plans for a new invention. ForensiC APPLiCAtions: to hide evidence audio steganography is used Anti-soCiAL eVents: Terrorists can also use Audio data hiding to keep their communications secret and to coordinate attacks.
  • 37. 37 • Difficult to detect and only receiver can detect. • Avoid ability of degradation and robustness for audio signals. • Protection of Intellectual digital works. • Internet privacy. • Secret communication between the organization like border security force and organization.
  • 38. 38 • Once algorithm known- confidentiality of information is lost. • Hackers may misuse the technique. • Due to distortion original signal may not be obtained.
  • 39. 39 As EVERY COIN HAS TWO SIDES, this technology besides having many benefits to make the internet business very safe and transmitting the defense messages secretly, it is also a threat to the society if it is used by anti social elements. “It will be more helpful if this technology is used in a proper way. The Steganography which we are seeing today is just an ice cap, we have to wait until it melts (ie. developed fully) to decide whether it is helpful to the society or not.”
  • 40. 40 HANKY OUT!!! THANK YOU
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