Is it really that hard to get the fingerprint sensor on mobile? It has been the great disappointment of our preliminary analysis of the Samsung Galaxy S8 +: the spectacular designs without just frames has relegated to the back the fingerprint sensor, but its position and operation has not convinced us at all. In fact that design decision of Samsung could be even worse in the case of the iPhone 8. The latest rumors point to a design that would put the Touch ID sensor also behind but also in the central part of the device, where reaching it will be even more rare. Why innovate when others are already right with fingerprint readers in the back? Beware of what you do with the Touch ID sensor, Apple The rumors about the new iPhone are accumulating, and this week we were already pointing out how one of the three models planned for its presentation will arrive with a curved screen and without just frames. That will have the same consequence as that design had on the Galaxy S8 \/ S8 +, and apparently will force to place the Touch Id sensor on the back of the device. Although it is known that Apple is working with several designs and this might not be definitive, the filtered image shows an opening in the central part of the back cover that would be dedicated to the TouchID sensor. That design would make reaching the sensor with the finger out especially uncomfortable, forcing a gesture that should be much more natural. The result could be worse than the decision of Samsung, which according to some rumors was taken at the last minute: although Synaptics had worked on a fingerprint sensor under the screen, it seems that the results of that combination were not good, something that led To the signature to place it next to the posterior chamber. The funny thing about it is that Samsung (and maybe Apple) would be making decisions that would break with that "if it works, do not touch it" rule. Many manufacturers and devices use the fingerprint sensor on the back, and we have seen how that option worked just as well as the front sensor (some prefer the sensor on one side and others on the other). But what we had never complained about was that the position of the sensor made it "unnatural" to use it, something that it seems that Samsung has achieved and that Apple seems to be threatening to do. We can not understand it: the fingerprint sensor on the back is just as valid as on the front, but it has to be centered (for ease of use for both right and left-handers) and a natural height that makes the gesture ergonomic. It has no mystery, does it not?