• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.676-682
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• 2018

As the IoT world including WSNs develops, the number of sensor systems that sense information according to the environment based on the principle of IoT is increasing. In order to perform security for each sensor system in such a complicated environment, the security modules must be varied. These problems make hardware/software implementation difficult when considering the system efficiency and hacking/cracking. Therefore, to solve this problem, this paper proposes a pseudorandom number generator (FLT: Pseudo-random Number Generator with Fixed Length Tap unrelated to the variable sensing nodes) with a fixed-length tap that generates a pseudorandom number with a constant period, irrespective of the number of sensing nodes, and has the purpose of detecting anomalies. The proposed FLT-LFSR architecture allows the security level and overall data formatting to be kept constant for hardware/software implementations in an IoT environment. Therefore, the proposed FLT-LFSR architecture emphasizes the scalability of the network, regardless of the ease of implementation of the sensor system and the number of sensing nodes.

• Convergence Security Journal
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• v.12 no.4
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• pp.17-23
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• 2012

Recently, the research for cryptographic algorithm, in particular, a stream cipher has been actively conducted for wireless devices as growing use of wireless devices such as smartphone and tablet. LFSR based random number generator is widely used in stream cipher since it has simple architecture and it operates very fast. However, the conventional multi-LFSR RNG (random number generator) suffers from its hardware complexity as well as very closed correlation between the numbers generated. A leap-ahead LFSR was presented to solve these problems. However, it has another disadvantage that the maximum period of the generated random numbers are significantly decreased according to the relationship between the number of the stages of the LFSR and the number of the output bits of the RNG. This paper presents new leap-ahead LFSR architecture to prevent this decrease in the maximum period by applying segmentation technique to the conventional leap-ahead LFSR. The proposed architecture is implemented using VHDL and it is simulated in FPGA using Xilinx ISE 10.1, with a device Virtex 4, XC4VLX15. From the simulation results, the proposed architecture has only 20% hardware complexity but it can increases the maximum period of the generated random numbers by 40% compared to the conventional Leap-ahead archtecture.

• Journal of IKEEE
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• v.24 no.2
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• pp.543-549
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• 2020

As the importance of security increases in various fields, research on a random number generator (RNG) used for generating an encryption key, has been actively conducted. A high-quality RNG is essential to generate a high-performance encryption key, but the initial pseudo-random number generator (PRNG) has the possibility of predicting the encryption key from the outside even though a large amount of hardware resources are required to generate a sufficiently high-performance random number. Therefore, the demand of high-quality true random number generator (TRNG) generating random number through various noises is increasing. This paper examines and compares the representative TRNG methods based on metastable-based and ring-oscillator-based TRNGs. We compare the methods how the random sources are generated in each TRNG and evaluate its performances using NIST SP 800-22 tests.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.5
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• pp.501-507
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• 2005

This paper proposes a Hybrid Random PWM(HRPWM) technique using a LF2407 DSP board in order to spread the power spectra of an induction motor. The proposed method is composed to the PRBS (Pseudo-Random Binary Sequence) with the Lead-Lag random bit and the random triangular carrier for the logical comparison. Also, a DSP generates the random number, the PRBS and the three-phase reference signal, a MAX038 chip operating as frequency modulator generates the random triangular carrier. For verification of the proposed method, the experiments were conducted with a three-phase adjustable speed a.c drives, and the results of simulations and experiments are presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.357-364
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• 2022

A pseudo-random number generator (PRNG) is a program used when a large amount of random numbers is needed. It is used to generate symmetric keys in symmetric key cryptography systems, generate public key pairs in public key cryptography or digital signatures, and generate columns used for padding with disposable pads. Cellular Automata (CA), which is useful for specific representing nonlinear dynamics in various scientific fields, is a discrete and abstract computational system that can be implemented in hardware and is applied as a PRNG that generates keys in cryptographic systems. In this paper, I propose an algorithm for synthesizing a programmable 5-neighbor CA based PRNG that can effectively generate a nonlinear sequence using 5-neighbor CA with the radius of the neighboring cell increased by 2.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.51-58
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• 2014

A LFSR is commonly used for various stream cryptography applications to generate random numbers. A Leap-ahead LFSR was presented to generate a multi-bits random number per cycle. It only requires a single LFSR and it has an advantages in hardware complexity. However, it suffers from the significant reduction of maximum period of the generated random numbers. This paper presents the new segmented Leap-ahead LFSR to solve this problem. It consists of two segmented LFSRs. We prove the efficiency of the proposed segmented architecture using the precise mathematical analysis. We also demonstrate the proposed comparison results with other counterparts using Xinilx Vertex5 FPGA. The proposed architecture can increase 2.5 times of the maximum period of generated random numbers compared to the typical Leap-ahead architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.112-121
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• 2002

In this paper, we present a design of a hash processor for data security systems. Two standard hash algorithms, Sha-1(American) and HAS-1600(Korean), are implemented on a single hash engine to support real time processing of the algorithms. The hash processor can also be used as a PRNG(Pseudo-random number generator) by utilizing SHA-1 hash iterations, which is being used in the Intel software library. Because both SHA-1 and HAS-160 have the same step operation, we could reduce hardware complexity by sharing the computation unit. Due to precomputation of message variables and two-stage pipelined structure, the critical path of the processor was shortened and overall performance was increased. We estimate performance of the hash processor about 624 Mbps for SHA-1 and HAS-160, and 195 Mbps for pseudo-random number generation, both at 100 MHz clock, based on Samsung 0.5um CMOS standard cell library. To our knowledge, this gives the best performance for processing the hash algorithms.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.104-110
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• 2003

In this paper, we proposed hybrid cryptosystem of Diffie-Hellman base in Elliptic Curve, and explained for specific protocol design. The proposed system is efficient hybrid cryptosystems system that offer implicit key authentication about sender and receiver unlike existing hybrid system. This system increased safety generating session key using pseudo-random number generator by cryptographic. Because the system is hybrid system, it is more efficient in calculation amount aspect supplementing merit and fault of public key system and secret key system. Also, the system can not get right plaintext except receiver even if sender's secret key is revealed and impersonation attack is impossible. And the system offers security on known keys without influencing in safety of other session's cryptogram even if session key is exposed. And the system is provided safety about mutual entity authentication and replay attack.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.243-248
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• 2021

Although many different types of covert channels have been suggested in the literature, there are little work in directly applying game theory to building up covert channel. This is because researchers have mainly focused on tailoring game theory for covert channel analysis, identification, and covert channel problem solving. Unlike typical adaptation of game theory to covert channel, we show that game theory can be utilized to establish a new type of covert channel in IoT devices. More specifically, we propose a covert channel that can be constructed by utilizing the Nash Equilibrium with sensor data collected from IoT devices. For covert channel construction, we set random seed to the value of sensor data and make payoff from random number created by running pseudo random number generator with the configured random seed. We generate I × J (I ≥ 2, J ≥ 2) matrix game with these generated payoffs and attempt to obtain the Nash Equilibrium. Covert channel construction method is distinctly determined in accordance with whether or not to acquire the Nash Equilibrium.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1539-1550
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• 2016

In modern society, the number of applications, which needs storage, is increased. Among them, the advance of FinTech increased the importance of storage encryption. FinTech storage, storing sensitive information, should be kept secure. Unless the storage is kept, many users will be damaged monetarily. To prevent this problem, we should encrypt the storage. A EncFS, which is one of the most popular storage encryption application, uses different IVs for each block to provide higher levels of security in the encryption algorithm. However, there is a vulnerability related to the usage of same IVs. In this paper, we propose a technique that decrypts the ciphertexts without knowing the secret key by using the vulnerability. Moreover, we show that the EncFS is not secure under IND-CPA model and propose a new scheme which is secure under IND-CPA model.