Black hat groups often portrayed in popular culture, and are "the epitome of all that the public fears in a computer criminal". Black hat hackers break into secure networks to destroy, modify, or steal data, or to make the networks unusable for authorized network users. Black hat A black hat hacker (or black-hat hacker) is a hacker who "violates computer security for little reason beyond maliciousness or for personal gain". The term's origin is often attributed to hacker culture theorist Richard Stallman (though he denies coining it) to contrast the exploitative hacker with the white hat hacker who hacks protectively by drawing
Colour recovery frequency, known as the "colour subcarrier". Black and white televisions do not decode this extra colour information in the subcarrier, using only the luminance to provide a monochrome picture. However, due to limited bandwidth in the video channel, the chrominance and luminance signals bleed into each other considerably, resulting in the colour information showing up visibly as Chroma Crawl, or Chroma dots on black & white TV sets. This is normally considered a nuisance in analogue broadcasting. However, since telerecordings were made from black & white TV screens and technicians at the time often decided not to apply a filter