Black-box testing and white-box testing are two approaches to test design that differ in the way they derive test cases from the test basis. Black-box testing is based on an analysis of the test basis documentation, such as requirements, specifications, user stories, or use cases, without looking at the internal structure or code of the system under test. White-box testing is based on an analysis of the code itself, such as statements, branches, paths, or data flows, to design test cases that cover specific aspects of the code. Black-box testing focuses on the external behavior and functionality of the system, while white-box testing focuses on the internal logic and structure of the system.
References: Certified Tester Foundation Level Syllabus, Section 4.3