White-box engagements are any time you provide the hacker as much details about the goal system or application as possible. This helps them find vulnerabilities more rapidly than it would generally have a malicious hacker. KnowBe4 CEO and founder Stu Sjouwerman described the incident in the site put up yesterday, https://thebookmarkage.com/story17948446/hire-a-hacker-in-california-for-dummies