Lattice PUF: A Strong Physical Unclonable Function Provably Secure against Machine Learning Attacks
share
We propose a strong physical unclonable function (PUF) that is provably secure against machine learning (ML) attacks with both classical and quantum computers. The security is derived from cryptographic hardness of learning decryption functions of semantically secure public-key cryptosystems within the probably approximately correct framework. The proposed lattice PUF compactly realizes the decryption function of the learning-with-errors (LWE) public-key cryptosystem as the core block. The lattice PUF is lightweight and fully digital. It is constructed using a weak PUF, as a physically obfuscated key (POK), an LWE decryption function block, a pseudo-random number generator in the form of a linear-feedback shift register, a self-incrementing counter, and a control block. The POK provides the secret key of the LWE decryption function. A fuzzy extractor is utilized to ensure stability of the POK. The proposed lattice PUF significantly improves upon a direct implementation of LWE decryption function in terms of challenge transfer cost by exploiting distributional relaxations allowed by recent work in space-efficient LWEs. To prevent an active attack in which arbitrary challenges can be submitted, the value of a self-incrementing counter is embedded into the challenge seed. We construct a lattice PUF that realizes a challenge-response pair space of size 2^136, requires 1160 POK bits, and guarantees 128-bit ML resistance. Assuming a bit error rate of 5 The PUF shows excellent uniformity, uniqueness, and reliability. We implement the PUF on a Spartan 6 FPGA. It requires only 4545 slices for the lattice PUF proper, and 233 slices for the fuzzy extractor.
READ FULL TEXT