Grey hat he violated their policies making this a grey hat incident. Grey hat The term "grey hat", alternatively spelled as "greyhat" or "gray hat", refers to a computer hacker or computer security expert who may sometimes violate laws or typical ethical standards, but does not have the malicious intent typical of a black hat hacker. The term began to be used in the late 1990s, derived from the concepts of "white hat" and "black hat" hackers. When a white hat hacker discovers a vulnerability, they will exploit it only with permission and not divulge its existence until it has been fixed,
Cyclic prefix Cyclic prefix In telecommunications, the term cyclic prefix refers to the prefixing of a symbol, with a repetition of the end. The receiver is typically configured to discard the cyclic prefix samples, but the cyclic prefix serves two purposes: For the cyclic prefix to serve its objectives, it must have a length at least equal to the length of the multipath channel. The concept of a cyclic prefix is traditionally associated with OFDM systems, however the cyclic prefix is now also used in single carrier systems to improve the robustness to multipath propagation. A cyclic prefix is often used in