Security hacker another crime such as destroying information contained in that system". These subgroups may also be defined by the legal status of their activities. A white hat hacker breaks security for non-malicious reasons, either to test their own security system, perform penetration tests, or vulnerability assessments for a client - or while working for a security company which makes security software. The term is generally synonymous with ethical hacker, and the EC-Council, among others, have developed certifications, courseware, classes, and online training covering the diverse arena of ethical hacking. A "black hat" hacker is a hacker who "violates computer security for
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