Smartphone sensors as random bit generators

Finding good entropy sources, designing deterministic (pseudo) random number generators, or simply finding suitable non-deterministic random number generators are major challenges. The goal of this paper is to evaluate the use of three motion sensors present in smartphones as potential nondeterministic, true random bit generators (TRNG). This paper focuses in particular on sensors present in Samsung Galaxy S3 and S4 devices. Data from the sensors was collected and submitted to the NIST STS v-2.1.1 test suite and the resulting bits were found fit enough to be used as the output of a TRNG. In addition, 4 SHA versions were used to whiten the data (as per NIST recommendation). Their conditioning performance was compared to each other, and found to be very close.