STEGANOGRPAHY [APPLICATION – I]

DIVYA C. (106111025)MAHALAKSHMI (106111055)GURLEEN KAUR (106111106)

STEGANOGRAPHY

Audio Steganography

Embedded Data

Audio File

Hidden MESSAGE

Types of Audio SteganographyLSB CodingPhase CodingEcho Data HidingSpread Spectrum

Receives the audio file convert it into bit pattern.

Step1

Each character in the message is converted into bit pattern.

Step 2 Check

which LSB to Replace By RC4 Algorithm

Step 3

Replaces the LSB bit from audio with LSB bit from character in the message.

Step 4

LSB

Low Computational ComplexityEasier Implementation

RC4 Algorithm

Phase Coding

• Audio phase components are imperceptible to the human ear

• Rather than adding noises, this technique encodes the secret data bits to phase shifts in the phase spectrum of the audio signal, attaining inaudible encodings in terms of signal-to-noise ratio.

pi/2 if Bit=0-pi/2 if Bit=1

Spread spectrumA form of Radio Frequency communication.

Data sent using spread spectrum is intentionally spread over a wide frequency range.

Appears as noise, so it is difficult to detect and jam.

Resistant to interference thus increasing the probability that the signal will be received correctly.

Unlikely to interfere with other signals even if they are transmitted on the same frequency.

Secret communications system used by the military.

Echo introduced to hide data into audio signalEcho is varied with three parameters:

Amplitude

Decay Rate (Delay time)

Offset

Echo Data Hiding

If the offset or delay is short then the echo produced will be unperceivable.

Also, initial amplitude and decay rate can also be set below the audible threshold of the human ear.

Inaudible echo

Advantages of audio Steganography

Human limitations – 20.000 Hz.Large amount of data that can be hidden insideHard to recognize because of the continuous flow

of information