What is the difference between the white box, black box, and gray box testing?

Black box Testing : The strategy of black box testing is based on requirements and specification. It requires no need of knowledge of internal path, structure or implementation of the software being tested.

White box Testing : White box testing is based on internal paths, code structure, and implementation of the software being tested. It requires a full and detail programming skill.

Gray box Testing : This is another type of testing in which we look into the box which is being tested, It is done only to understand how it has been implemented. After that, we close the box and use the black box testing.

Black box testing	Gray box testing	White box testing
Black box testing does not need the implementation knowledge of a program.	Gray box testing knows the limited knowledge of an internal program.	In white box testing, implementation details of a program are fully required.
It has a low granularity.	It has a medium granularity.	It has a high granularity.
It is also known as opaque box testing, closed box testing, input-output testing, data-driven testing, behavioral testing and functional testing.	It is also known as translucent testing.	It is also known as glass box testing, clear box testing.
It is a user acceptance testing, i.e., it is done by end users.	It is also a user acceptance testing.	Testers and programmers mainly do it.
Test cases are made by the functional specifications as internal details are not known.	Test cases are made by the internal details of a program.	Test cases are made by the internal details of a program.