STEGANOGRPAHY [APPLICATION – I] DIVYA C. (106111025) MAHALAKSHMI (106111055) GURLEEN KAUR (106111106)

STEGANOGRAPHY 2

Embedded Data Hidden MESSAGE Audio File Audio Steganography 3

Types of Audio Steganography LSB Coding Phase Coding Echo Data Hiding Spread Spectrum

LSB Step 4 Step 2 Step1 Step 3 Low Computational Complexity Easier Implementation Step 4 Step 2 Replaces the LSB bit from audio with LSB bit from character in the message. Each character in the message is converted into bit pattern. Receives the audio file convert it into bit pattern. Check which LSB to Replace By RC4 Algorithm Step1 Step 3 5

RC4 Algorithm 6

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 spectrum A 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 Data Hiding Echo introduced to hide data into audio signal Echo is varied with three parameters: Amplitude Decay Rate (Delay time) Offset

Inaudible echo 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.

Advantages of audio Steganography Human limitations – 20.000 Hz. Large amount of data that can be hidden inside Hard to recognize because of the continuous flow of information