Echo Steganography

A form of hiding data within the echos of audio in a audio file. Artificial echos are created with:

• Short delay (1ms) = 0

• Long delay (2ms) = 1 $s(n)=x(n)+\alpha \times x(n-d)$

• $s(n)$ is the stego-signal (audio with hidden data)

• $x(n)$ is the original audio signal

• $\alpha$ is the attenuation factor (typically 0.1 to 0.5)

• $d$ is the delay in samples

• $n$ is the sample index