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The technology is an all-printed Physically Unclonable Function (PUF) electronic device based on a nanomaterial (such as single-walled carbon nanotube) network. The network may be a mixture of semiconducting and metallic nanotubes randomly tangled with each other through the printing process. The all-printed PUF electronic device comprises a nanomaterial ink that is inkjet deposited, dried, and randomly tangled on a substrate, creating a network. A plurality of electrode pairs is attached to the substrate around the substrate perimeter. Each nanotube in the network can be a conduction path between electrode pairs, with the resistance values varying among individual pairs and between networks due to inherent inter-device and intra-device variability. The unique resistance distribution pattern for each network may be visualized using a contour map based on the electrode information, providing a PUF key that is a 2D pattern of analog values. The PUF security keys remain stable and maintain robustness against security attacks. Although local resistance change may occur inside the network (e.g., due to environmental impact), such change has little effect on the overall pattern. In addition, when a network-wide resistance change occurs, all resistances are affected together, so that the unique pattern is maintained.

Advances in additive manufacturing have enabled development of printable electronic sensor elements that can be deposited onto flexible substrates. To benchmark performance of printed sensors against the state of the art, NASA developed a low power flexible sensor platform. The platform integrates the following key components and features: -Flexible substrate: DuPont Kapton allows bending around cylindrical surfaces as small as in diameter. -Embedded microcontroller: Cypress CY8C4248 LQI-BL583 Arm Cortex M0 processor with BLE wireless controller, max frequency 48 MHz. Supports low power modes of operation, capacitive sensing support, and a single-channel 12-bit AD converter. -Commercial sensor suite: Bosch BNO080 inertial sensor; Bosch BME280 humidity, pressure, and temperature sensor; AMS CCS811 air quality sensor (VOCs and CO2). -Prototyping area for custom-printed sensors: 1) thermistor, uses carbon-based PTC resistor paste DuPont2792; 2) capacitive humidity sensor using a NASA-developed dielectric ink. NASA researchers have used the platform to study performance of the printed capacitive humidity sensor. The 2x4 mm co-doped barium titanate sensing element is highly sensitive to water vapor and performs as an unobtrusive breathing monitor, sensitive to breath at distances of up to 20 cm. Average change of sensor capacitance at a distance of 7.5 cm was observed to be 6.23.5 pF.