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We propose a novel computer architectural concept of instruction overloading to support block ciphers. Instead of adding new instructions, we extend only the execution of some existing instructions. The proposed method allows a central processing unit core to execute different operations for the same instructions, depending on the address of the data, similar to operator overloading in object-oriented languages. We first present an extension for the AES algorithm, then we demonstrate its enhanced applicability with two further extensions supporting multiple block ciphers and hardware masking. The first extension for AES is also applicable to add/AND-rotate-XOR-based block ciphers such as SIMON. The AES and SIMON encryption speed, on this extended core, is at least doubled and is significantly less affected by memory latency. In addition, the AES encryption code requires only 18% of the memory of the previous software implementation. The second extension can further support various block ciphers defined over GF(28), and the SM4 encryption speed is increased by at least 182%. The third extension provides correlation power analysis (CPA) resistance with a 66.6% area overhead but almost no speed overhead, whereas a typical software anti-CPA AES implementation requires at least hundreds of times the execution time.

In 2020 and 2021, humanity lived in fear due to the COVID-19 pandemic. However, with the development of artificial intelligence technology, mankind is attempting to tackle many challenges from currently unpredictable epidemics. Korean society has been exposed to various infectious diseases since the Korean War in 1950, and to overcome them, the six most serious cases in National Notifiable Infectious Diseases (NNIDs) category I were defined. Although most infectious diseases have been overcome, viral hepatitis A has been on the rise in Korean society since 2010. Therefore, in this paper, the prediction of viral hepatitis A, which is rapidly spreading in Korean society, was predicted by region using the deep learning technique and a publicly available dataset. For this study, we gathered information from five organizations based on the open data policy: Korea Centers for Disease Control and Prevention (KCDC), National Institute of Environmental Research (NIER), Korea Meteorological Agency (KMA), Public Open Data Portal, and Korea Environment Corporation (KECO). Patient information, water environment information, weather information, population information, and air pollution information were acquired and correlations were identified. Next, an epidemic outbreak prediction was performed using data preprocessing and 3D LSTM. The experimental results were compared with various machine learning methods through RMSE. In this paper, we attempted to predict regional epidemic outbreaks of hepatitis A by linking the open data environment with deep learning. It is expected that the experimental process and results will be used to present the importance and usefulness of establishing an open data environment.

We propose a privacy-preserving face authentication system for smartphones that guarantees security against malicious clients. Using the proposed system, a face feature vector is stored on a remote server in encrypted form. To guarantee security against an honest-but-curious server who may try to learn the private feature vector, we perform a Euclidean distance-based matching score computation on encrypted feature vectors using homomorphic encryption. To provide security against malicious clients, we adopt a blinding technique. We implement the proposed system on a mobile client and a desktop server. Through an experiment with real-world participants, we demonstrate that secure face verification can be completed in real time (within 1.3 s) even when a smartphone is involved, with an Equal Error Rate (EER) of 3.04%. In further experiments with two public face datasets, CFP and ORL, face verification is completed in approximately 1 s with EER of 1.17% and 0.37%, respectively. Our system is two orders of magnitude faster than previous privacy-preserving face verification method with the same security assumptions and functionalities. To achieve this secure real-time computation, we improve the Catalano-Fiore transformation which converts a linear homomorphic encryption scheme into a quadratic scheme, and parallelize the decryption procedure of our system.

In many bandwidth-critical environments, including vehicle-to-vehicle and vehicle-to-infrastructure communications, implicit certificates such as elliptic curve Qu-Vanstone (ECQV) are frequently employed as a means to reduce the bandwidth requirement of digital signatures. In these environments, however, certain recipients such as roadside units need to verify signatures for multiple messages within considerably short time periods. In this paper, we propose two efficient methods of reducing the computational costs of signature verification when multiple digital signatures are provided together with the ECQV implicit certificates. The first method achieves this by sharing the intermediate results that are computed when public keys are extracted from ECQV certificates. The second guarantees a further speed improvement by merging the public key extraction processes into a batch signature verification process. We also present an algorithm that adaptively chooses the best verification method for the given signatures in real time. Our experimental results show that the proposed methods allow for a signature verification that is five times faster than existing methods.

With the recent advances in mobile technologies, biometric verification is being adopted in many smart devices as a means for authenticating their owners. As biometric data leakage may cause stringent privacy issues, many proposals have been offered to guarantee the security of stored biometric data, i.e., biometric template. One of the most promising solutions is the use of a remote server that stores the template in an encrypted form and performs a biometric comparison on the ciphertext domain, using recently proposed functional encryption (FE) techniques. However, the drawback of this approach is that considerable computation is required for the inner-pairing product operation used for the decryption procedure of the underlying FE, which is performed in the authentication phase. In this paper, we propose an enhanced method to accelerate the inner-pairing product computation and apply it to expedite the decryption operation of FE and for faster remote biometric verification. The following two important observations are the basis for our improvement—one of the two arguments for the decryption operation does not frequently change over authentication sessions, and we only need to evaluate the product of multiple pairings, rather than individual pairings. From the results of our experiments, the proposed method reduces the time required to compute an inner-pairing product by 30.7%, compared to the previous best method. With this improvement, the time required for biometric verification is expected to decrease by up to 10.0%, compared to a naive method.

The rapidly increasing expansion of distributed energy resources (DER), such as renewable energy systems and energy storage systems into the electric power system and the integration of advanced information and communication technologies enable DER owners to participate in the electricity market for grid services. For more efficient and reliable power system operation, the concept of peer-to-peer (P2P) energy trading has recently been proposed. The adoption of blockchain technology in P2P energy trading has been considered to be the most promising solution enabling secure smart contracts between prosumers and users. However, privacy concerns arise because the sensitive data and transaction records of the participants, i.e., the prosumers and the distribution system operator (DSO), become available to the blockchain nodes. Many efforts have been made to resolve this issue. A recent breakthrough in a P2P energy trading system on an Ethereum blockchain is that all bid values are encrypted using functional encryption and peer matching for trading is performed securely on these encrypted bids. Their protocol is based on a method that encodes integers to vectors and an algorithm that securely compares the ciphertexts of these vectors. However, the comparison method is not very efficient in terms of the range of possible bid values because the amount of computation grows linearly according to the size of this range. This paper addresses this challenge by proposing a new bid encoding algorithm called dual binary encoding, which dramatically reduces the amount of computation as it is only proportional to the square of the logarithm of the size of the encoding range. Moreover, we propose a practical mechanism for rebidding the remaining amount caused when the amounts from the two matching peers are not equal. Finally, the feasibility of the proposed method is evaluated by using a virtual energy trade testbed and a private Ethereum blockchain platform.

Advanced smart grid technologies enable energy prosumers to trade surplus energy from their distributed renewable energy sources with other peer prosumers through peer-to-peer (P2P) energy trading. In many previous works, P2P energy trading was facilitated by blockchain technology through blockchain’s distributive nature and capacity to run smart contracts. However, the feature that all the data and transactions on a blockchain are visible to all blockchain nodes may significantly threaten the privacy of the parties participating in P2P energy trading. There are many previous works that have attempted to mitigate this problem. However, all these works focused on the anonymity of participants but did not protect the data and transactions. To address this issue, we propose a P2P energy trading system on a blockchain where all bids are encrypted and peer matching is performed on the encrypted bids by a functional encryption-based smart contract. The system guarantees that the information encoded in the encrypted bids is protected, but the peer matching transactions are performed by the nodes in a publicly verifiable manner through smart contracts. We verify the feasibility of the proposed system by implementing a prototype composed of smart meters, a distribution system operator (DSO) server, and private Ethereum blockchain.

We proposed a high-performance elliptic curve cryptography (ECC) processor over NIST prime fields. Instead of applying a full modular reduction to a $2{k}$ -bit product, the proposed partial modular reduction method iteratively performs reductions on partial products whose bit length is slightly greater than ${k}$ , where ${k}$ is the bit length of field elements. As a result, the computational complexity of modular multiplication (MM) was significantly reduced. Moreover, the amount of computation is configurable by parameterizing the size of the partial products. This is a very desirable characteristic of the proposed ECC processor, because the hardware complexity and processing time of the entire ECC processor can be adjusted according to the requirements of various Internet of Things environments. Including the proposed MM module, finite field operation modules are integrated into a single module to further reduce the required resources. The proposed ECC processor synthesized using 180-nm CMOS process technology can perform a 256-bit elliptic curve point multiplication in 0.20–0.74 ms with 144.8k–65.4k gate counts. These results and the experimental results in various FPGA devices show that the proposed ECC processor has significantly better throughput per area than the previously reported ones.

We present a new Personal Identification Number (PIN) entry method for smartphones that can be used in security-critical applications, such as smartphone banking. The proposed “Two-Thumbs-Up” (TTU) scheme is resilient against observation attacks such as shoulder-surfing and camera recording, and guides users to protect their PIN information from eavesdropping by shielding the challenge area on the touch screen. To demonstrate the feasibility of TTU, we conducted a user study for TTU, and compared it with existing authentication methods (Normal PIN, Black and White PIN, and ColorPIN) in terms of usability and security. The study results demonstrate that TTU is more secure than other PIN entry methods in the presence of an observer recording multiple authentication sessions.

The biggest cause of the epidemic is “unpredictable.” In Korea, the number of patients with hepatitis A has been increasing recently, and the government enacted a law in 1954 to effectively manage diseases such as hepatitis A. The purpose of this paper is to design a model for predicting trends in order to minimize the damage caused by the prevalence of infectious diseases. As a tool for it, various statistical techniques and Supervised Learning of Machine Learning and LSTM techniques were used. To this end, data were collected using Web Crawling and other data, correlation analysis using Regression analysis was conducted, and prediction models were designed using Machine Learning and LSTM.

The development of smart meters that can frequently measure and report power consumption has enabledelectricity providers to offer various time-varying rates, including time-of-use and real-time pricing plans. High-resolution power consumption data, however, raise serious privacy concerns because sensitive information regarding an individual’s lifestyle can be revealed by analyzing these data. Although extensive research has been conducted to address these privacy concerns, previous approaches have reduced the quality of measured data. In this paper, we propose a new privacy-preserving electricity billing method that does not sacrifice data quality for privacy. The proposed method is based on the novel use of functional encryption. Experimental results on a prototype system using a real-world smart meter device and data prove the feasibility of the proposed method.

User authentication is a process in which a user of a system proves his/her identity to acquire access permission. An effective user authentication method should be both secure and usable. In an attempt to achieve these two objectives, Bianchi et al. recently proposed novel unimodal PIN-entry methods that use either audio or vibration cues. This paper analyzes the security of their method, in particular, the vibration version of one of their proposals, Timelock. A probabilistic analysis and real attack experiment reveal that the security level guaranteed by Timelock is lower than that claimed in Bianchi et al.’s paper. As countermeasures to this problem, three PIN-entry methods are proposed and a usability study is performed. According to the result of this study, a simple modification may improve the security significantly while retaining the design philosophy of unimodal systems. In addition, the proposed methods address the PIN compatibility issue of Timelock and they can be used to enter a legacy numerical PIN without any change in the PIN.

We present an efficient hardware prime generator that generates a prime p by combining trial division and Fermat test in parallel. Since the execution time of this parallel combination is greatly influenced by the number k of the smallest odd primes used in the trial division, it is important to determine the optimal k to create the fastest parallel combination. We present probabilistic analysis to determine the optimal k and to estimate the expected running time for the parallel combination. Our analysis is conducted in two stages. First, we roughly narrow the range of optimal k by using the expected values for the random variables used in the analysis. Second, we precisely determine the optimal k by using the exact probability distribution of the random variables. Our experiments show that the optimal k and the expected running time determined by our analysis are precise and accurate. Furthermore, we generalize our analysis and propose a guideline for a designer of a hardware prime generator to determine the optimal k by simply calculating the ratio of M to D, where M and D are the measured running times of a modular multiplication and an integer division, respectively.

Currently, an increasing number of smartphones are adopting fingerprint verification as a method to authenticate their users. Fingerprint verification is not only used to unlock these smartphones, but also used in financial applications such as online payment. Therefore, it is very crucial to secure the fingerprint verification mechanism for reliable services. In this paper, however, we identify a few vulnerabilities in one of the currently deployed smartphones equipped with fingerprint verification service by analyzing the service application. We demonstrate actual attacks via two proof-of-concept codes that exploit these vulnerabilities. By the first attack, a malicious application can obtain the fingerprint image of the owner of the victimized smartphone through message-based interprocess communication with the service application. In the second attack, an attacker can extract fingerprint features by decoding a file containing them in encrypted form. We also suggest a few possible countermeasures to prevent these attacks.

In this paper, we introduce a transaction authentication solution that provides compatibility with any banking transactions. Our solution is based on a novel visual cryptographic scheme that supports multiple uses of a single static share, unlike existing techniques in the literature of visual cryptography. To support multiple uses, we utilize complementary colors in the subtractive color mixing model. In our solution, a user is asked to overlap an issued visual cryptography card on an encrypted image that is rendered on a screen to check transaction information and transaction authentication number. We analyze the security of our scheme against various attacks and show its effectiveness using a usability study.

Finite field multiplication is a crucial building block for cryptography, especially the elliptic curve public key cryptosystem. Recently, various algorithms for efficient finite field multiplication over devices whose resources are extremely constrained have been proposed. However, most of these proposals only take speed optimization into account, but they do not pay much attention to optimization of memory usage. In this paper, we propose a multiplication algorithm on $F_{2^{m}}$ , which minimizes the RAM requirement by rescheduling operation sequences. According to our experimental results on the ATmega128L microprocessor, the proposed algorithm reduces the amount of required RAM by up to 50 % while maintaining the speed at the same level. We also verify the feasibility of our algorithm by applying it to the elliptic curve cryptosystem.

AIMS The study investigated the clinical equivalence in reducing haemoglobin A1c (A1C) between glimepiride/metformin sustained release (GM-SR) 2/500 mg, a fixed-dose combination, once daily and glimepiride/metformin (GM) 1/250 mg, a fixed-dose combination, twice daily in patients with type 2 diabetes (T2D). METHODS A multicentre, randomised, double-blind, double-dummy study was conducted in 14 hospitals in Korea. Inclusion criteria were age 30-75 years, T2D diagnosis no longer than 10 years previously, A1C between 7% and 10%, and body mass index

Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communications are considered as building blocks in many promising applications related to traffic safety and management. However, network security issues related to V2V and V2I communications should be considered together for more robust service. For example, message recipients (vehicles or road side units) should be able to verify the origin and integrity of a message by verifying the signature corresponding to the message. Because in some cases a recipient has to verify a large number of signatures in a short time period, faster signature verification is required. In this paper, we show that the signature verification process can be accelerated by sharing public key extraction processes between messages and we propose an efficient algorithm for fast signature verification. Our proposal can be applied to both separate verification and batch verification scenarios.

Biometric verification systems have security issues regarding the storage of biometric data in that a user's biometric features cannot be changed into other ones even when a system is compromised. To address this issue, it may be safe to store the biometrics data on a reliable remote server instead of storing them in a local device. However, this approach may raise a privacy issue. In this paper, we propose a biometric verification system where the biometric data are stored in a remote server in an encrypted form and the similarity of the user input to the registered biometric data is computed in an encrypted domain using a homomorphic encryption. We evaluated the performance of the proposed system through an implementation on an Android-based smartphone and an i7-based server.

Since card-type one-time password (OTP) generators became available, power and area consumption has been one of the main issues of hardware OTPs. Because relatively smaller batteries and smaller chip areas are available for this type of OTP compared to existing tokentype OTPs, it is necessary to implement power-efficient and compact dedicated OTP hardware modules. In this paper, we design and implement a low-power small-area hardware OTP generator based on the Advanced Encryption Standard (AES). First, we implement a prototype AES hardware module using a 350 nm process to verify the effectiveness of our optimization techniques for the SubBytes transform and data storage. Next, we apply the optimized AES to a real-world OTP hardware module which is implemented using a 180 nm process. Our experimental results show the power consumption of our OTP module using the new AES implementation is only 49.4% and 15.0% of those of an HOTP and softwarebased OTP, respectively.

A physical unclonable function (PUF) based on process variations on silicon wafers is a very promising technology which finds various applications in identification and authentication, but only a few integrated circuits have been reported so far. As those circuits are vulnerable to power supply noises, switching noises and environmental variations, they lead to a reliability issue such as time-varying or metastable responses. To resolve this issue, this letter proposes a new integrated circuit design for PUFs using differential amplifiers. The feasibility of the proposed circuit has been theoretically analyzed and validated through HSPICE simulations for the previous and proposed circuits.

The NTRU cryptosystem is a public key system based on lattice problems. While its theoretical security has been well studied, little effort has been made to analyze its security against implementation attacks including power analysis attacks. In this paper, we show that a typical software implementation of NTRU is vulnerable to the simple power analysis and the correlation power analysis including a second-order power attack. We also present novel countermeasures to prevent these attacks, and perform experiments to estimate the performance overheads of our countermeasures. According to our experimental results, the overheads in required memory and execution time are only 8.17% and 9.56%, respectively, over a Tmote Sky equipped with an MSP430 processor.

Passwords and personal identification numbers (PINs) are convenient and ubiquitous, but they are quite vulnerable to attackers who stand near the user (“shoulder-surfers”). This problem may be partially resolved by changing the user interface, but previous solutions of this kind still give shoulder-surfing attackers a significant advantage over brute force search. This paper provides a novel solution based on three dimensions, particularly suitable for glasses-free three-dimensional (3D) displays found in many smartphones and handheld game consoles. A user at the “3D spot” may log in easily, while nearby shoulder-surfers gain no advantage. A detailed experimental usability analysis is performed to demonstrate the effectiveness of the proposed scheme in comparison to the existing methods.

A very promising application of active RFID systems is the electronic seal, an electronic device to guarantee the authenticity and integrity of freight containers. To provide freight containers with a high level of tamper resistance, the security of electronic seals must be ensured. In this paper, we present the design and implementation of an electronic seal protection system. First, we propose the eSeal Protection Protocol (ePP). Next, we implement and evaluate various cryptographic primitives as building blocks for our protocol. Our experimental results show that AES-CBC-MAC achieves the best performance among various schemes for message authentication and session key derivation. Finally, we implement a new electronic seal system equipped with ePP, and evaluate its performance using a real-world platform. Our evaluation shows that ePP guarantees a sufficient performance over an ARM9based interrogator.

Currently, many smartphones are adopting fingerprint verification as a method to authenticate their users. Because fingerprint verification is not only used to unlock these smartphones but also used in financial applications such as online payment, it is crucial to secure the fingerprint verification mechanism for reliable services. In this paper, we identify a few vulnerabilities in one of the currently deployed smartphones equipped with fingerprint verification service by analyzing the service application. We demonstrate actual attacks via a proof-of-concept code that exploits these vulnerabilities. By these attacks, an attacker can extract fingerprint features by decoding a file containing them in encrypted form. We also suggest a few possible countermeasures against these attacks.

Von zur Gathen proposed an efficient parallel exponentiation algorithm in finite fields using normal basis representations. In this paper we present a processor-efficient parallel exponentiation algorithm in GF(qn) which improves upon von zur Gathen's algorithm. We also show that exponentiation in GF(qn) can be done in O((log2 n)2 / logq n) time using n / (log2 n)2 processors. Hence we get a processor-time bound of O(n / logq n), which matches the best known sequential algorithm. Finally, we present an efficient on-line processor assignment scheme which was missing in von zur Gathen's algorithm.

Passwords and PINs are convenient and ubiquitous, yet they are quite vulnerable to attackers who stand near the user. This problem may be partially resolved by changing the user interface, but previous solutions of this kind still give shoulder-surfing attackers a significant advantage over brute-force search. We propose a novel solution based on 3D, especially suitable for glasses-free 3D displays found in many smartphones and handheld game consoles. A user at the “3D spot” may log in easily, while nearby shoulder-surfers gain no advantage. We perform a detailed experimental analysis of the usability of our scheme.

We propose a new PIN-entry method which prevents shoulder surfing attacks effectively. The proposed method uses a random mapping between the PIN digits and alphabets given as challenges to the users. The user’s task is to recognize this mapping and to enter the mapped alphabet sequence instead of directly entering the PIN digits. The intuitive nature and easy interface of the proposed scheme enables the users to learn it easily, and the experimental results in the pilot test show that the new method guarantees fast and reliable authentication. To be precise, the average authentication time was 5.8 to 6.8 seconds, and the average error rate was 3.3 to 6.7%.

We propose a novel authentication method that uses smart phones and 2-D barcodes. Using our method, a user can access a system by just taking a picture of a challenge code displayed in the target system.

Personal identification number (PIN) is a common user authentication method widely used for ATMs and mobile phones. However, an attacker can obtain the PIN easily by looking over a user's shoulder. We present a new PIN entry method which makes this kind of attack significantly harder.

User authentication is a mechanism that enables a user of a system to prove his identity and to have access to the system. Traditionally, there are three categories of authentication mechanisms based on what we know, what we are, and what we have. In this paper, we show some possible weaknesses in the third class of schemes and we propose a new user authentication scheme based on distance estimation using ultrasonic communication.

One of the most promising applications of active RFID tags is electronic seal, which is an electronic device to guarantee the authenticity and integrity of freight containers and also provides physical protection like a lock. There are already many commercial electronic seal products and ongoing standardization activities such as ISO-18185 drafts. While electronic seals can provide freight containers with a high level of tamper resistance, the security problem of electronic seal itself should be solved, and a feasible solution would be to use symmetric key cryptography based primitives such as block ciphers and message authentication codes (MACs). This kind of approach has already been used in many security-related standards and it requires the implementation of pseudorandom functions (PRFs) for key derivation and authentication. In this paper, we consider secure and efficient implementation of PRFs on electronic seals and interrogators. We implement block cipher based PRFs and hash based PRFs and compare them from the viewpoint of efficiency. Since practical PRFs can be directly implemented using MACs, we consider implementation of various message authentication schemes; HMAC-MD5, HMAC-SHA1, AES-CBC-MAC, AES-CMAC and AESXCBC-MAC. For interrogators, we design FPGA modules for these MAC algorithms since an interrogator has to guarantee high throughput to communicate with many electronic seals simultaneously. According to our analysis, AES based MACs consume smaller areas and their throughputs are significantly higher than hash based ones. For electronic seals, we implement MAC algorithms as a form of software module (C and assembly codes) over a small-scale microcontroller. Our experimental results show that AES based modules show much better performance, which coincide with the results in hardware implementation. Finally, we improve the above implementations further, where we concentrate on the optimization of AES based MACs. We use several well-known techniques such as use of block RAMs in FPGA, and loop unrolling and register reallocation in assembly code.

Since Wolfram proposed to use cellular automata as pseudorandom sequence generators, many cryptographic applications using cellular automata have been introduced. One of the recent one is Mukherjee, Ganguly, and Chaudhuri's message authentication scheme using a special class of cellular automata called Single Attractor Cellular Automata (SACA). In this paper, we show that their scheme is vulnerable to a chosen-message attack, i.e., the secret key can be recovered by an attacker using only several chosen message-MAC pairs. The weakness of the scheme results from the regularity of SACA.

The NTRU cryptosystem is a ring-based public key system using hard problems over lattices. There has been an extensive research on efficient implementation of NTRU operations, including recent results such as Bailey et al.'s software implementation over a resource-constrained device and Gaubatz et al.'s hardware implementation using only 3,000 gates. In this paper, we present a new algorithm to improve further the performance of NTRU. We speed up the encryption and decryption operations of NTRU up to 32% using some temporary memory, and if we can use precomputation, then the speed-up becomes up to 37%. Our method is based on the observation that specific sub-operations are repeated frequently in the underlying polynomial operations of NTRU.

Recently, Mukherjee, Ganguly, and Chaudhuri proposed a message authentication scheme using a special class of cellular automata called Single Attractor Cellular Automata (SACA). In this paper, we show that their scheme is vulnerable to a chosen-message attack, i.e., the secret key can be recovered by an attacker using only several chosen message-MAC pairs. The weakness of the scheme results from the regularity of SACA.

We propose a variant of the self-shrinking generator, which is constructed using an extended selection rule. This new generator is called SSG-XOR since the selection rule is determined by the XORed value of a couple of bits. It is shown that the period and the linear complexity of an output sequence of SSG-XOR are better than those of the self-shrinking generator. It is also shown that the SSG-XOR generator has meaningful advantages from the viewpoint of practical cryptanalysis.

Elliptic curve cryptography (ECC) was discovered by Koblitz and Miller, and there has been a vast amount of research on its secure and efficient implementation. To implement ECC, three kinds of finite fields are being widely used, i.e. prime field GF(p), binary field GF(2m) and optimal extension field GF(pm). There is an extensive literature on hardware implementation of prime fields and binary fields, but almost nothing is known about hardware implementation of OEFs. At a first glance, this may seem natural because OEF has been devised originally for efficient software implementation of ECC. However, we still need its hardware implementation for the environments where heterogeneous processors are communicating with each other using a single cryptographic protocol. Since the ECC software implementation over the weaker processor may not guarantee reasonable performance, a customized ECC coprocessor would be a good solution. In this paper, we propose an ECC coprocessor over GF(pm) on an FPGA. Since the most resource-consuming operation is inversion, we focus on the efficient design of inversion modules. First we provide four different implementations for inversion operation, i.e. three variants of Extended Euclidian Algorithm and inversion using the iterative Frobenius map. We use them as the building blocks of our ECC coprocessor over OEF. According to our analysis, inversion using the iterative Frobenius map shows the best performance among the four choices, from the viewpoints of speed and area.

The Simple Power Analysis (SPA) attack against an elliptic curve cryptosystem is to distinguish between point doubling and point addition in a single execution of scalar multiplication. Although there have been many SPA-resistant scalar multiplication algorithms, there are no known countermeasures for simultaneous scalar multiplication. In this paper, we propose an SPA-resistant simultaneous scalar multiplication algorithm using scalar recoding. The computational and memory overheads of our scheme are almost negligible.

In this paper, we will present the design and implementation of the crypto coprocessors which can be used for providing the RFID security. By analyzing the power consumption characteristics of our crypto coprocessors, we can see which crypto algorithms can be used for highly resource constrained applications such as RFID. To provide the security mechanism such as integrity and authentication between the RFID tag and the RFID reader, crypto algorithm or security protocol should be implemented at the RFID tag and reader. Moreover, the security mechanism in the RFID tag should be implemented with low power consumption because the resources of RFID tag are highly constrained, that is, the RFID tag has low computing capability and the security mechanism which operates in the RFID tag should be low power consumed. After investigating the power consumption characteristics of our designed crypto processors, we will conclude which crypto algorithm is suitable for providing the security of RFID systems.

In 2008, Dimitrov et al. proposed a point multiplication algorithm on Koblitz curves using multiple-base expansions. They claimed that their algorithm is the first provably sublinear point multiplication algorithm on Koblitz curves. In this paper, we show that the well-known τ-adic NAF method is already sublinear and also guarantees a better average performance.