According to one embodiment, a data storage apparatus includes a processor. The processor protects data on a memory by encryption in a first mode or a second mode. The processor stores a first image, a second image and a third image. The first image reproduces a first state which is an initial state where the data storage apparatus is set to neither the first mode nor the second mode. The second image reproduces a second state which is an initial state in the first mode. The third image reproduces a third state which is an initial state in the second mode. The processor is capable of performing a first process to transition from the first state to the second state, and performing a second process to transition from the first state to the third state.