1,442 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,
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