Different Black Box Testing Techniques :
"Black" means which is unable to see, further it is done by tester at test environment.
ECP (Equivalent Class Partition) : dividing input data into class of partition in order to generate test cases from it. Also to cover more partition.
BVA (Boundary Value Analysis): It will check the test data for each boundary value. Having Valid & invalid data set one can easily make an idea which test case to be choose for execution & which is not.