white hat

A white hat (or a white-hat hacker, a whitehat) is an ethical security hacker. Under the owner's consent, white-hat hackers deliberately hack software or system with the aim of identifying any vulnerabilities or security issues it has, helping to reinforce it from black hat hackers.

The white hat is contrasted with the black hat, a malicious hacker; this definitional dichotomy comes from Western films, where heroic and antagonistic cowboys might traditionally wear a white and a black hat, respectively. There is a third kind of hacker known as a grey hat who hacks with good intentions but at times without permission or proper consent.