Silicon Proven 1.8μm × 9.2 μm 65-nm Digital Bit Generator for Hardware Security Applications

Many circuit/gate level countermeasures require randomness to provide immunity against power analysis attacks. These applications usually require up to 64 bit sequences at different locations in the design in parallel. While these sequences are not required to be truly random, they must be independent. In this brief, we present, for the first time, results of silicon proven compact bit generator (cBG). The measurements prove that cBGs are able to amplify random fluctuations in the supply voltage to successfully produce the required bit sequences. The results show that less than 0.00014 random bits (out of 4 bits) are lost because of the negligible dependence between neighbouring generators. Additionally, the generators produce high enough entropy (minimum of 0.9656 over 10 Mbits) so they can be used as distributed generators for gate level countermeasures. The generators were tested with clock frequencies up to 100 MHz and the measured energy per bit of a single generator is 45 pJ@100 MHz.