2,542 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
Time-domain Physical Unclonable Functions
One can replace one-way functions (also known as hash functions) commonlyfound in cryptography with physical processes, known as physical unclonable functions (PUFs). Optical PUFs have been devised based on the complex response ofscattering media to the spatial wavefront. However, such PUFs are intrinsicallyunpractical for use over larger distances. In this project, we design PUFs with atime-domain scattering response (tPUF), whose readout can be performed over asingle spatial mode, in our case an optical fiber. These tPUFs are networks of microring resonators, whose transfer function is highly complex and vary strongly from realization to realization as a result of manufacturing imperfections. Thesedevices are developed for pulses with a very low number of average photons perpulse which negates any attempts at reading out the pulse shape in transit, therebyeliminating eavesdropping. These PUFs can then be used for a variety of applicationsin asymmetric cryptography, such as proof of identity and secure messaging
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
Effects of Kerr nonlinearity in physical unclonable functions
We address the question of whether the presence of Kerr nonlinearity in
multiple-scattering optical media offers any advantage with respect to the
design of physical unclonable functions. Our results suggest that under certain
conditions, nonlinear physical unclonable functions can be more robust against
the potential cloning of the medium, relative to their linear counterparts that
have been exploited in the context of various cryptographic applications
Modeling attacks on physical unclonable functions
We show in this paper how several proposed Physical Unclonable Functions (PUFs) can be broken by numerical modeling attacks. Given a set of challenge-response pairs (CRPs) of a PUF, our attacks construct a computer algorithm which behaves indistinguishably from the original PUF on almost all CRPs. This algorithm can subsequently impersonate the PUF, and can be cloned and distributed arbitrarily. This breaks the security of essentially all applications and protocols that are based on the respective PUF. The PUFs we attacked successfully include standard Arbited PUFs and Ring Oscillator PUFs of arbitrary sizes, and XO Arbiter PUFs, Lightweight Secure PUFs, and Feed-Forward Arbiter PUFs of up to a given size and complexity. Our attacks are based upon various machine learning techniques including Logistic Regression and Evolution Strategies. Our work leads to new design requirements for secure electrical PUFs, and will be useful to PUF designers and attackers alike.Technische Universitat Munche
Emerging physical unclonable functions with nanotechnology
Physical unclonable functions (PUFs) are increasingly used for authentication and identification applications as well as the cryptographic key generation. An important feature of a PUF is the reliance on minute random variations in the fabricated hardware to derive a trusted random key. Currently, most PUF designs focus on exploiting process variations intrinsic to the CMOS technology. In recent years, progress in emerging nanoelectronic devices has demonstrated an increase in variation as a consequence of scaling down to the nanoregion. To date, emerging PUFs with nanotechnology have not been fully established, but they are expected to emerge. Initial research in this area aims to provide security primitives for emerging integrated circuits with nanotechnology. In this paper, we review emerging nanotechnology-based PUFs
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