36 research outputs found
Analysis of Communication Channels Related to Physical Unclonable Functions
Cryptographic algorithms rely on the secrecy of their corresponding keys. On embedded systems with standard CMOS chips, where
secure permanent memory such as flash is not available as a key storage, the secret key can be derived from Physical Unclonable Functions
(PUFs) that make use of minuscule manufacturing variations of, for instance, SRAM cells. Since PUFs are affected by environmental changes,
the reliable reproduction of the PUF key requires error correction. For
silicon PUFs with binary output, errors occur in the form of bitflips
within the PUF response. Modeling the channel as a Binary Symmetric
Channel (BSC) with fixed crossover probability p is only a first-order
approximation of the real behavior of the PUF response. We propose a
more realistic channel model, referred to as the Varying Binary Symmetric Channel (VBSC), which takes into account that the reliability of
different PUF response bits may not be equal. We investigate its channel
capacity for various scenarios which differ in the channel state information (CSI) present at encoder and decoder. We compare the capacity
results for the VBSC for the different CSI cases with reference to the
distribution of the bitflip probability according to a work by Maes et al
Analysis of Communication Channels Related to Physical Unclonable Functions
Cryptographic algorithms rely on the secrecy of their corresponding keys. On embedded systems with standard CMOS chips, where
secure permanent memory such as flash is not available as a key storage, the secret key can be derived from Physical Unclonable Functions
(PUFs) that make use of minuscule manufacturing variations of, for instance, SRAM cells. Since PUFs are affected by environmental changes,
the reliable reproduction of the PUF key requires error correction. For
silicon PUFs with binary output, errors occur in the form of bitflips
within the PUF response. Modeling the channel as a Binary Symmetric
Channel (BSC) with fixed crossover probability p is only a first-order
approximation of the real behavior of the PUF response. We propose a
more realistic channel model, referred to as the Varying Binary Symmetric Channel (VBSC), which takes into account that the reliability of
different PUF response bits may not be equal. We investigate its channel
capacity for various scenarios which differ in the channel state information (CSI) present at encoder and decoder. We compare the capacity
results for the VBSC for the different CSI cases with reference to the
distribution of the bitflip probability according to a work by Maes et al