Feasibility and Infeasibility of Secure Computation with Malicious PUFs

Abstract

A recent line of work has explored the use of physically uncloneable functions (PUFs) for secure computation, with the goals of (1) achieving universal composability without additional setup, and/or (2) obtaining unconditional security (i.e., avoiding complexity-theoretic assumptions). Initial work assumed that all PUFs, even those created by an attacker, are honestly generated. Subsequently, researchers have investigated models in which an adversary can create malicious PUFs with arbitrary behavior. Researchers have considered both malicious PUFs that might be stateful, as well as malicious PUFs that can have arbitrary behavior but are guaranteed to be stateless. We settle the main open questions regarding secure computation in the malicious-PUF model: • We prove that unconditionally secure oblivious transfer is impossible, even in the standalone setting, if the adversary can construct (malicious) stateful PUFs. • If the attacker is limited to creating (malicious) stateless PUFs, then universally composable two-party computation is possible without computational assumptions.

Weakening the Isolation Assumption of Tamper-Proof Hardware Tokens

“…It was shown that PUFs can be used to achieve oblivious transfer [27] and UC-secure commitments [12]. However, if the PUFs can be created maliciously, oblivious transfer is impossible [10].…”

Everlasting UC Commitments from Fully Malicious PUFs

“…Reproducibility informally says that, the responses produced by the PUF when queried on the same random challenge are always close. Many PUF definitions in the literature [3,4,12,30] have had problems with the superpolynomial nature of PUFs. In particular, the possibility of PUFs solving hard computational problems, such as discrete logarithms or factoring, was not excluded, or excluded in an awkward way.…”

“…Dachman-Soled et al [12] 2PC Unconditional PUF ✗ Badrinarayanan et al [4] 2PC Unconditional PUF ✗ Our scheme (Sect. 6) Commitments Everlasting PUF ✓…”

“…However, as shown by [4] in the form of an attack, the construction of [17] completely breaks when the adversary is allowed to generate encapsulated PUFs. Dachman-Soled, Fleischhacker, Katz, Lysyanskaya, and Schröder [12] investigated the possibility of secure two-party computation based on malicious PUFs. Badrinarayanan, Khurana, Ostrovsky, and Visconti [4] introduced a model where the adversary is allowed to generate malicious PUFs that encapsulate other PUFs inside of it; the outer PUF has oracle access to all its inner PUFs.…”