How do you hide information such as messages inside WAV file?

Answer 1

It's called steganography. Clear-text or cipher-text is merged with existing data and, depending on the format, slightly alters the existing data to conceal the source data. For example, if I'm sending you a complex color picture with high resolution and 24 or more bits per pixel, I can "steal" 1 or 2 low order bits for my own uses. This would probably cause a chance in the color picture so minor human eyes cannot discern that it's there at all. As such, this method lends itself to large media - small messaeg transmissions most effectively. For instance, if the carrier picture is pure white and the cipher text is more than half the number of bits of the carrier, the casual obsever would be able to see artifacts -- weird darker shapes on the field of white. While this alone won't reveal what the ciphertext message is, it Will show that this picture carries a steganographic subliminal message. The same works with large, high-bit WAV files, where the embedded message can be rendered virtually invisible, especially if the stolen bits produce sound on playback that is near the outer ranges of human hearing. However, if a steganographic message is embedded on a recording of silence, audio artifacts would be discernable.