You are safe with ICTK
ICTK가 걸어온 길

"ICTK홀딩스는 PUF 교과서에 명시된, '항상성'(Homeostasis)이란 난제를 푼 유일한 기술업체다."

-PUF in Theory and Practice 中

2019 해외에서 빛난 ICTKA PUF taxonomy


Authentication is an essential cryptographic primitive that confirms the identity of parties during communications. For security, it is important that these identities are complex, in order to make them difficult to clone or guess. In recent years, physically unclonable functions (PUFs) have emerged, in which identities are embodied in structures, rather than stored in memory elements. PUFs provide “digital fingerprints,” where information is usually read from the static entropy of a system, rather than having an identity artificially programmed in, preventing a malicious party from making a copy for nefarious use later on. Many concepts for the physical source of the uniqueness of these PUFs have been developed for multiple different applications. While certain types of PUF have received a great deal of attention, other promising suggestions may be overlooked. To remedy this, we present a review that seeks to exhaustively catalogue and provide a complete organisational scheme towards the suggested concepts for PUFs. Furthermore, by carefully considering the physical mechanisms underpinning the operation of different PUFs, we are able to form relationships between PUF technologies that previously had not been linked and look toward novel forms of PUF using physical principles that have yet to be exploited.

A Physically Unclonable Function (PUF) is a hardware security fundamental that translates an input challenge into an output response through a physical system in a manner that is specific to the exact hardware instance (unique) and cannot be replicated (unclonable). This allows the system, and by extension any object or device it is attached to or embedded within, to be uniquely authenticated. At the point of manufacture, the system is subjected to one or more challenges, and the response to these challenges is taken and recorded. From then on, it is known that if a challenge is repeated at any point and its expected response is verified, the device must be the same as the one characterised previously. The characteristics of a PUF are to be robust (stable over time), unique (so no two PUFs are the same), easy to evaluate (to be feasibly implemented), difficult to replicate (so the PUF cannot be copied), and very difficult or impossible to predict (so the responses cannot be guessed). Many concepts have been put forward as candidates for PUFs. Some, such as the Arbiter PUF, have become very well established with a large number of variations (such as the basic Arbiter PUF,1 N-XOR Arbiter PUF,2 Double Arbiter PUF,3 and so forth). Others, such as the MEMS PUF4 or BoardPUF,5 do not appear to have significant current industry focus. While papers exist that provide information and organisation to a selection of proposed PUFs, no paper sets out to provide a full review and organisation scheme for all suggested PUFs at the concept level and above. This review will attempt to exhaustively catalogue all the different concepts that have been suggested as ways to implement PUFs and to create a coherent taxonomic system to organise them. This is achieved by first introducing preliminary information (Sec. II) to provide context for the review that follows. The section following this information introduces three different systems of classification (Sec. III). Once these classification systems are discussed, a large number of PUF concepts are listed and explained, ordered by an organic classification system that lends itself to this listed format (Sec. IV). An example of a PUF concept arranged in this organic scheme would be the static random access memory (SRAM) PUF.6 The SRAM PUF is ordered within a section on volatile memory (including similar volatile-memory-cell PUFs such as the DRAM PUF7 and the MEmory Cell-based Chip Authentication (MECCA) PUF8), which is in turn within a higher-order section of implicit/intrinsic PUFs (alongside racetrack and direct characterisation PUF sections). Finally, the section of implicit/intrinsic PUFs, along with explicit/extrinsic PUFs, is within the classification of all-electronic PUFs (as opposed to “hybrid” PUFs, which probe the unique characteristic of the physical system in a non-electronic way, such as using light). The final sections of this report (Secs. V and VI) provide a number of observations that became apparent as a result of arranging and cataloguing these PUF concepts.

A. Weak and strong PUFs

A key distinctive property of PUFs is what is described as the strength of their implementation.9 There are two levels of PUF strength—weak and strong. The strength of the PUF depends on the number of challenge response pairs (CRPs) that can be generated from a single device. This, in turn, typically corresponds to how the number of CRPs increases with the increasing device size. This rate of scaling tends to act as the metric that determines the strength of a PUF, although exceptions are argued and will be discussed later in this chapter. Weak PUFs support a relatively small number of CRPs, typically as a consequence of a low-order rate of scaling. This means that the full set of these pairs can be read from the device should an attacker gain physical access to the PUF for any given time. While it would not be possible to copy the physical PUF itself, with knowledge of the PUF's CRPs an attacker could convincingly respond to query as if they still possessed the device—long after the device has left their possession. Weak PUFs can be used for secure key storage and entity authentication techniques, for instance, using the protocol featured in Fig. 1. However, for authentication purposes, the PUF must be examined in an environment where an authenticating party is present to ensure that the PUF itself is being evaluated.

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PUF Technology


What is PUF?

복제가 불가능한 Unique Inborn ID (PUF, Physically Unclonable Functions)

• 반도체 제조 공정 상에서 수동소자 생성의 

랜덤성을 이용한 Silicon Inborn ID

• 물적 특성으로 생성되는 Physical ID로서 

값을 변조하거나 복제하는 것이 원천적으로 불가

• 반도체 칩마다 다른 고유한 ID를 발생시키므로 

반도체의 지문이라 일컫는다

어떠한 사이버 공격에도 끄떡없는 불변의 함수이며

 IoT 보안의 근간이 된다

PUF Advantages

Via PUF는 고유한 Silicon Inborn ID의 특성을 제공함으로써 모든 신뢰의 원천인 Root of Trust (RoT)를 제공한다.

• Via PUF는 다양한 형태의 해킹 공격에도 뚫리지 않는
 안정성을 보장해 준다

• Via PUF는 반도체 공정 중 메탈 층 사이의 Via hole 형성의 
미세 공차를 이용하여 PUF를 구현한 기술이다.

• Passive 수동소자 방식으로서 기존 기술의 문제점을
 모두 해결해 주는 혁신적인 방식이다

• 랜덤성, 항상성, 보안성을 모두 만족하는 PUF

• 다른 기술과 달리 에러 보정 회로 (ECC)가 필요치 않다

What you can do with PUF

VIA PUF는 강력한 보안을 필요로 하는 각종 IoT기기와 솔루션에 적용 가능합니다.

• ICTK의 보안칩은 PUF로 생성된 키를 기반으로ECC라는 알고리즘을 이용해서 개인키와 공개키의 키쌍을 보안칩 내에서 생성하게 됩니다

• ICTK의 PUF 보안칩은 내부에 암호화된 RAM (Random Access Memory)과 암호화된 eFlash (플래쉬 메모리)를 제공합니다.

• ICTK의 보안칩은 양자보안 알고리즘인 PQC (Post Quantum Cryptography) 등에서 구동 가능합니다. 

• ICTK의 보안칩은 PUF를 기반으로 해서 Root of Trust 기능을 제공하는 현존하는 가장 강력한 방법입니다