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2020 PUF meets QuantumPhysical unclonable function

A physical unclonable function (sometimes also called physically unclonable function, which refers to a weaker security metric than a physical unclonable function), or PUF, is a physical object that for a given input and conditions (challenge), provides a physically defined "digital fingerprint" output (response) that serves as a unique identifier, most often for a semiconductor device such as a microprocessor. PUFs are most often based on unique physical variations which occur naturally during semiconductor manufacturing. A PUF is a physical entity embodied in a physical structure. Today, PUFs are usually implemented in integrated circuits and are typically used in applications with high security requirements, more specifically cryptography.


Early references about systems that exploit the physical properties of disordered systems for authentication purposes date back to Bauder in 1983[1] and Simmons in 1984.[2][3] Naccache and Frémanteau provided an authentication scheme in 1992 for memory cards.[4] The terms POWF (physical one-way function) and PUF (physical unclonable function) were coined in 2001[5] and 2002,[6] the latter publication describing the first integrated PUF where, unlike PUFs based on optics, the measurement circuitry and the PUF are integrated onto the same electrical circuit (and fabricated on silicon).

Starting in 2010, PUF gained attention in the smartcard market as a promising way to provide "silicon fingerprints", creating cryptographic keys that are unique to individual smartcards.[7][8]

PUFs are now established as a secure alternative to battery-backed storage of secret keys in commercial FPGAs, such as the Xilinx Zynq Ultrascale+,[9] and Altera Stratix 10.[10]


PUFs depend on the uniqueness of their physical microstructure. This microstructure depends on random physical factors introduced during manufacturing. These factors are unpredictable and uncontrollable, which makes it virtually impossible to duplicate or clone the structure.

Rather than embodying a single cryptographic key, PUFs implement challenge–response authentication to evaluate this microstructure. When a physical stimulus is applied to the structure, it reacts in an unpredictable (but repeatable) way due to the complex interaction of the stimulus with the physical microstructure of the device. This exact microstructure depends on physical factors introduced during manufacture which are unpredictable (like a fair coin). The applied stimulus is called the challenge, and the reaction of the PUF is called the response. A specific challenge and its corresponding response together form a challenge–response pair or CRP. The device's identity is established by the properties of the microstructure itself. As this structure is not directly revealed by the challenge–response mechanism, such a device is resistant to spoofing attacks.

Using a fuzzy extractor or the fuzzy commitment scheme that are provably suboptimal in terms of storage and privacy leakage amount or using nested polar codes[11] that can be made asymptotically optimal, one can extract a unique strong cryptographic key from the physical microstructure.[12] The same unique key is reconstructed every time the PUF is evaluated.[13][14] The challenge–response mechanism is then implemented using cryptography.[citation needed]

PUFs can be implemented with a very small hardware investment. Unlike a ROM containing a table of responses to all possible challenges, which would require hardware exponential in the number of challenge bits, a PUF can be constructed in hardware proportional to the number of challenge and response bits. In some cases PUFs can even be built from existing hardware with the right properties.

Unclonability means that each PUF device has a unique and unpredictable way of mapping challenges to responses, even if it was manufactured with the same process as a similar device, and it is infeasible to construct a PUF with the same challenge–response behavior as another given PUF because exact control over the manufacturing process is infeasible. Mathematical unclonability means that it should be very hard to compute an unknown response given the other CRPs or some of the properties of the random components from a PUF. This is because a response is created by a complex interaction of the challenge with many or all of the random components. In other words, given the design of the PUF system, without knowing all of the physical properties of the random components, the CRPs are highly unpredictable. The combination of physical and mathematical unclonability renders a PUF truly unclonable.[13][15]

Note that a PUF is "unclonable" using the same physical implementation, but once a PUF key is extracted, there's generally no problem to clone the key – the output of the PUF – using other means.

Because of these properties PUFs can be used as a unique and untamperable device identifier. PUFs can also be used for secure key generation and storage as well as for a source of randomness.


Main article: Types of physical unclonable function

Over 40 types of PUF have been suggested.[16] These range from PUFs that evaluate an intrinsic element of a pre-existing integrated electronic system[17] to concepts that involve explicitly introducing random particle distributions to the surface of physical objects for authentication.[18] All PUFs are subject to environmental variations such as temperature, supply voltage and electromagnetic interference, which can affect their performance. Therefore, rather than just being random, the real power of a PUF is its ability to be different between devices, but simultaneously to be the same under different environmental conditions on the same device.

Error correction

In many applications it is important that the output is stable. If the PUF is used for a key in cryptographic algorithms it is necessary that error correction be done to correct any errors caused by the underlying physical processes and reconstruct exactly the same key each time under all operating conditions. In principle there are two basic concepts: Pre-Processing and Post-Processing Error Correction.[19] [20]

Strategies have been developed which lead SRAM PUF to become more reliable over time without degrading the other PUF quality measures such as security and efficiency.[21]

Research at Carnegie Mellon University into various PUF implementations found that some error reduction techniques reduced errors in PUF response in a range of ~70 percent to ~100 percent.[22]

Research at the University of Massachusetts Amherst to improve the reliability of SRAM PUF-generated keys posited an error correction technique to reduce the error rate.[23]

Joint reliability–secrecy coding methods based on transform coding are used to obtain significantly higher reliabilities for each bit generated from a PUF such that low-complexity error-correcting codes such as BCH codes suffice to satisfy a block error probability constraint of 1 bit errors out of 1 billion bits.[24]

Nested polar codes are used for vector quantisation and error correction jointly. Their performance is asymptotically optimal in terms of, for a given blocklength, the maximum number of secret bits generated, minimum amount of private information leaked about the PUF outputs, and minimum storage required. The fuzzy commitment scheme and fuzzy extractors are shown to be suboptimal in terms of the minimum storage.[11]

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We do these things.
PUF Technology

What is PUF?

Unique Inborn ID 
(PUF, Physically Unclonable Functions)

•Silicon Inborn ID using the randomness of passive device generation in the semiconductor manufacturing process

• As a Physical ID created with physical characteristics, it is fundamentally impossible to falsify or duplicate the value

• Since each semiconductor chip generates a different unique ID, it is called a semiconductor fingerprint.

PUF Advantages

AS Via PUF provides unique Silicon Inborn ID characteristics,  It provides the Root of Trust (RoT), the source of all trust

•Via PUF guarantees stability that is impervious to 
various types of hacking attacks.

•Via PUF is a method of forming via holes between 
metal layers during semiconductor processing.

•As a passive device method, it is an innovative method
that solves all the problems of existing technologies.

•PUF that satisfies all randomness, homeostasis and 
security •Unlike other technologies, no error correction
circuit (ECC) is required.

What you can do with PUF

VIA PUF can be applied to various IoT devices and solutions  that require strong security.

•ICTK's security chip generates a key pair of a private key and a public key in the security chip using an algorithm called ECC based on the key generated by PUF.

•ICTK's PUF security chip provides encrypted RAM (Random Access Memory) and encrypted eFlash (flash memory) inside.

•ICTK's security chip can be operated in PQC (Post Quantum Cryptography), a quantum security algorithm.

ICTK's security chip is the most powerful existing method to provide the Root of Trust function based on PUF.