Fingerprinting with Wow

摘要

Wow, or time warping caused by speed fluctuations in analog audio equipment, provides a wealth of applications in watermarking. Very subtle temporal distortion has been used to defeat watermarks, and as components in watermarking systems. In the image domain, the analogous warping of an image's canvas has been used both to defeat watermarks and also proposed to prevent collusion attacks on fingerprinting systems. In this paper, we explore how subliminal levels of wow can be used for steganography and fingerprinting. We present both a low-bitrate robust solution and a higher-bitrate solution intended for steganographic communication. As already observed, such a fingerprinting algorithm naturally discourages collusion by averaging, owing to flanging effects when misaligned audio is averaged. Another advantage of warping is that even when imperceptible, it can be beyond the reach of compression algorithms. We use this opportunity to debunk the common misconception that steganography is impossible under "perfect compression."