423 research outputs found
A formal definition and a new security mechanism of physical unclonable functions
The characteristic novelty of what is generally meant by a "physical
unclonable function" (PUF) is precisely defined, in order to supply a firm
basis for security evaluations and the proposal of new security mechanisms. A
PUF is defined as a hardware device which implements a physical function with
an output value that changes with its argument. A PUF can be clonable, but a
secure PUF must be unclonable. This proposed meaning of a PUF is cleanly
delineated from the closely related concepts of "conventional unclonable
function", "physically obfuscated key", "random-number generator", "controlled
PUF" and "strong PUF". The structure of a systematic security evaluation of a
PUF enabled by the proposed formal definition is outlined. Practically all
current and novel physical (but not conventional) unclonable physical functions
are PUFs by our definition. Thereby the proposed definition captures the
existing intuition about what is a PUF and remains flexible enough to encompass
further research. In a second part we quantitatively characterize two classes
of PUF security mechanisms, the standard one, based on a minimum secret
read-out time, and a novel one, based on challenge-dependent erasure of stored
information. The new mechanism is shown to allow in principle the construction
of a "quantum-PUF", that is absolutely secure while not requiring the storage
of an exponentially large secret. The construction of a PUF that is
mathematically and physically unclonable in principle does not contradict the
laws of physics.Comment: 13 pages, 1 figure, Conference Proceedings MMB & DFT 2012,
Kaiserslautern, German
A new Definition and Classification of Physical Unclonable Functions
A new definition of "Physical Unclonable Functions" (PUFs), the first one
that fully captures its intuitive idea among experts, is presented. A PUF is an
information-storage system with a security mechanism that is
1. meant to impede the duplication of a precisely described
storage-functionality in another, separate system and
2. remains effective against an attacker with temporary access to the whole
original system.
A novel classification scheme of the security objectives and mechanisms of
PUFs is proposed and its usefulness to aid future research and security
evaluation is demonstrated. One class of PUF security mechanisms that prevents
an attacker to apply all addresses at which secrets are stored in the
information-storage system, is shown to be closely analogous to cryptographic
encryption. Its development marks the dawn of a new fundamental primitive of
hardware-security engineering: cryptostorage. These results firmly establish
PUFs as a fundamental concept of hardware security.Comment: 6 pages, 3 figures; Proceedings "CS2 '15 Proceedings of the Second
Workshop on Cryptography and Security in Computing Systems", Amsterdam, 2015,
ACM Digital Librar
Q-Class Authentication System for Double Arbiter PUF
Physically Unclonable Function (PUF) is a cryptographic primitive that is based on physical property of each entity or Integrated Circuit (IC) chip. It is expected that PUF be used in security applications such as ID generation and authentication. Some responses from PUF are unreliable, and they are usually discarded. In this paper, we propose a new PUF-based authentication system that exploits information of unreliable responses. In the proposed method, each response is categorized into multiple classes by its unreliability evaluated by feeding the same challenges several times. This authentication system is named Q-class authentication, where Q is the number of classes. We perform experiments assuming a challenge-response authentication system with a certain threshold of errors. Considering 4-class separation for 4-1 Double Arbiter PUF, it is figured out that the advantage of a legitimate prover against a clone is improved form 24% to 36% in terms of success rate. In other words, it is possible to improve the tolerance of machine-learning attack by using unreliable information that was previously regarded disadvantageous to authentication systems
Quantum Copy-Protection and Quantum Money
Forty years ago, Wiesner proposed using quantum states to create money that
is physically impossible to counterfeit, something that cannot be done in the
classical world. However, Wiesner's scheme required a central bank to verify
the money, and the question of whether there can be unclonable quantum money
that anyone can verify has remained open since. One can also ask a related
question, which seems to be new: can quantum states be used as copy-protected
programs, which let the user evaluate some function f, but not create more
programs for f? This paper tackles both questions using the arsenal of modern
computational complexity. Our main result is that there exist quantum oracles
relative to which publicly-verifiable quantum money is possible, and any family
of functions that cannot be efficiently learned from its input-output behavior
can be quantumly copy-protected. This provides the first formal evidence that
these tasks are achievable. The technical core of our result is a
"Complexity-Theoretic No-Cloning Theorem," which generalizes both the standard
No-Cloning Theorem and the optimality of Grover search, and might be of
independent interest. Our security argument also requires explicit
constructions of quantum t-designs. Moving beyond the oracle world, we also
present an explicit candidate scheme for publicly-verifiable quantum money,
based on random stabilizer states; as well as two explicit schemes for
copy-protecting the family of point functions. We do not know how to base the
security of these schemes on any existing cryptographic assumption. (Note that
without an oracle, we can only hope for security under some computational
assumption.)Comment: 14-page conference abstract; full version hasn't appeared and will
never appear. Being posted to arXiv mostly for archaeological purposes.
Explicit money scheme has since been broken by Lutomirski et al
(arXiv:0912.3825). Other quantum money material has been superseded by
results of Aaronson and Christiano (coming soon). Quantum copy-protection
ideas will hopefully be developed in separate wor
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