White Box Testing is software testing technique in which internal structure, design and coding of software are tested to verify flow of input-output and to improve design, usability and security.
Black Box Testing is a software testing method in which the functionalities of software applications are tested without having knowledge of internal code structure, implementation details and internal paths.

• While in Black Box Testing the main objective is to test the
  functionality/behavior of the system, in White Box Testing the main objective is to test the internal operation of the system.

• Black Box Testing can be performed by a tester without any coding knowledge whereas in White Box Testing, tester should have the knowledge of internal structure and how the system works.