This document discusses audio steganography, which is a means of hiding secret information in audio files. It describes how the least significant bit of audio samples can be modified to embed binary data by changing the order of the bits. The document provides examples of how secret text can be embedded within an audio file and then extracted. It also outlines some potential applications of audio steganography, such as secret communication, as well as some risks if it is misused.

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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

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The basic mechanisms for security of data are:

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•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

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PROCESS OF
CRYPTOGRAPHY

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STEGANOGRAPHY:
Steganography comes from the Greek
Word which means covered or secret message.
STEGAN-O-GRAPHY
COVERED + WRITING

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• 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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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.

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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

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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
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STEGnOGrAPhY TYPESSTEGnOGrAPhY TYPES
oPHYSICAL
oDIGITAL
oNETWORK
oSUDOKO PUZZLES
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oSteganography in Text
oSteganography in Images
oSteganography in Audio
Image steganography

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AUDIO STEGANOGRAPHY

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METHODS OF AUDIO
STEGANOGRAPHY
METHODS OF AUDIO
STEGANOGRAPHY

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LSB CODINGLSB CODING

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Variation in choosing LSBVariation in choosing LSB

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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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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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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:

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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:

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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

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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.

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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

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• 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):

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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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• 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.

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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.

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• 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.

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• Once algorithm known- confidentiality of
information is lost.
• Hackers may misuse the technique.
• Due to distortion original signal may not be
obtained.

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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.”

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HANKY OUT!!!
THANK YOU

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