A team of researchers from Purdue University has proven in practice the possibility of using 2D materials to protect logic circuits from attempts to reveal their functionality. The prototype of a chip with transistors based on monolayer black phosphorus (phosphorene), created as part of the experiment, showed during testing that in this way it is possible to effectively hide important information about the key elements of the microcircuit – the type of conductivity they use.
Identifying field-effect transistors by their type (n-channel or p-channel) allows reverse engineering of the logic circuit. This is used by both hackers and intellectual property rights defenders. Chip manufacturers usually protect their products from unwanted curiosity at the circuit level. The possibility of masking the functionality of individual elements has so far been considered only theoretically; the work of university researchers has shown that it is quite real.
The reality of using black phosphorus as an ultrathin semiconductor and creating field-effect transistors on its basis was proven several years ago. Researchers at Purdue University are also developing this topic and are the authors of one of the first experimental prototypes of a phosphorus-based transistor.
As it turned out, this material is also promising from the point of view of security at the hardware level. Belonging to N-type or P-type transistors gives the direction of the current, and the use of phosphorene makes this difference negligible.
“These two types of transistors can be thought of as a switch because they work differently in a circuit,” the researchers write . “Since the distinction between them is clear, they can be uniquely identified with the right tools. In our approach, N-type and P-type transistors at a basic level look the same, They cannot be distinguished if the key is unknown. After the chip is created, this key cannot be retrieved even by the manufacturer of such products. The chip, of course, can be stolen, but you won’t be able to get the key. ”
Phosphorus transistors are low voltage and operate at room temperature. New work has shown that the use of this material can improve not only the integration of circuits, but also their protection against hacking. However, the authors of the study did not fail to note that chip makers are likely to give preference to other two-dimensional films: modern technologies do not yet allow the use of such unstable materials as phosphoric to be put on stream.