Browsing by Author "Lin, Chu-Hsing"

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A TRANSPOSITIONAL ADVANCED ENCRYPTION STANDARD (AES) RESISTS 3-ROUND SQUARE ATTACK
(2009-05-01)
Yeh, Yi-Shiung
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Lee, Chen-Yu
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Huang, Ting-Yu
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Lin, Chu-Hsing
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資訊工程學系
In this paper, an advanced encryption standard (AES) variant is proposed that is resistant to linear cryptanalysis, differential cryptanalysis, and the square attack. We replace some procedures in the round function of AES and take the bit as the operation unit to foil the square attack. Also, we apply linear cryptanalysis and differential cryptanalysis to the proposed cipher. The proposed cipher is shown to be superior to AES in many aspects.
Finding Near-Optimum Message Scheduling Settings for SHA-256 Variants Using Genetic Algorithms
(2013-09-01)
Lin, Chu-Hsing
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Lee, Chen-Yu
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Kavi, Krishna M.
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Chen, Deng-Jyi
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Yeh, Yi-Shiung
One-way hash functions play an important role in modem cryptography. Matusiewicz et al. proved that the message scheduling is essential for the security of SHA-256 by showing that it is possible to find collisions with complexity 2(64) hash operations for a variant without it. In this article, we first proposed the conjecture that message scheduling of SHA algorithm has higher security complexity (or fitness value in Genetic algorithm) if each message word (W-t) involves more message blocks (M-i) in each round. We found some evidence supports the conjecture. Consider the security of SHA-0 and SHA-1. Since Chabaud and Joux shown that SHA-1 is more secure than SHA-0. Further, Wang found collisions in full SHA-0 and SHA-1 hash operations with complexities less than 2(39) and 2(69), respectively. We found it is consistent from the viewpoint of message blocks (terms) involved in each message word. It clearly shown that the number of terms involved in SHA-1 is more than that in SHA-0, taking W-27 as an example, 14 and 6, respectively. Based on the conjecture we proposed a new view of complexity for SHA-256-XOR functions, a variant of SHA-256, by counting the terms involved in each equation, instead of analyzing the probability of finding collisions within SHA-256-XOR hash function. Our experiments shown that the parameter set in each equation of message schedule is crucial to security fitness. We applied genetic algorithms to find the near-optimal message schedule parameter sets that enhance the complexity 4 times for SHA-1 and 1.5 times for SHA-256-XOR, respectively, when compared to original SHA-1 and SHA-256-XOR functions. The analysis would be interesting for designers on the security of modular-addition-free hash function which is good for hardware implementation with lower gate count. And the found message schedule parameter sets would be a good reference for further improvement of SHA functions.
Investigations of Factors Affecting the Genetic Algorithm for Shortest Driving Time
(2009)
Lin, Chu-Hsing
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Lee, Chen-Yu
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Liu, Jung-Chun
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Zuo, Hao-Tian
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資訊工程學系
In this paper we investigate the influences on the genetic algorithm for the shortest driving time problem due to factors such as nodes on a map, the population size, the mutation rate, the crossover rate, and the converging rate. When the nodes on the map increase, more execution time is needed and much difference between the approximate solution and the exact solution appear on running genetic algorithms. Also, from the view point of the population initialization, restart type and reback type affect the precision of approximate solutions and the execution time. The characteristics of the factors we find in the paper provide us insight how to improve the genetic algorithm for the shortest driving time problem.
Modified Autonomous Key Management Scheme with Reduced Communication/Computation Costs in MANET
(2010)
Lin, Chu-Hsing
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Lee, Chen-Yu
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資訊工程學系
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Department of Computer Science
The growing applications of Mobile Ad hoc Network (MANET) has made the security issue increasingly more important. B. Zhu et al. proposes a key management scheme using Shamir\'s secret sharing scheme to construct an Autonomous Key Management (AKM) hierarchy structure. However, Shamir\'s secret sharing in AKM to control key hierarchy needs larger message transmission costs. In this paper, we modify the secret sharing scheme and apply it to AKM for reducing communication and computation cost.
MODIFIED AUTONOMOUS KEY MANAGEMENT SCHEME WITH REDUCED COMMUNICATION/COMPUTATION COSTS IN MANET
(2011)
Lin, Chu-Hsing
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Lee, Chen-Yu
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Chen, Deng-Jyi
;
資訊工程學系
;
Department of Computer Science
The growing applications of mobile ad hoc networks (MANETs) have made related security issues much more important. B. Zhu et al. proposed a key management scheme using Shamir's secret sharing scheme to construct an Autonomous Key Management (AKM) hierarchy structure. However, Shamir's secret sharing in AKM to control key hierarchy incurs high message transmission costs. This paper modifies the secret sharing scheme and applies it to AKM to reduce communication and computation costs.
Unseen Visible Watermarking for Gray Level Images Based on Gamma Correction
(2011)
Lin, Chu-Hsing
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Lee, Chen-Yu
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Lu, Shu-Yuan
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Chien, Shih-Pei
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資訊工程學系
In this paper, we proposed a novel watermarking technology with the properties that from visible watermarking and invisible watermarking. In the common situation our approach can he used to transmit the multimedia files, according to the gamma correction. the watermark can be revealed. Our proposed method has a unique feature that we can obtain a watermarked-image similar to the original image after embedding watermarks. The naked eye hardly realized the watermarks, but after adjusting the viewing angle, it then demonstrated the embedded watermarks. We embed the unseen visible watermarks by adjusting degree of saturation and value of HSV model in the color space. The experiment result shows that the PSNR values of the watermarked images are more than 45 dB, sometimes even as high as 55 dB.
Visible Watermarking Based on Multi-parameters Adjustable Gamma Correction
(2011)
Lin, Chu-Hsing
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Lee, Chen-Yu
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Yang, Tzu-Chien
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Lai, Shin-Pin
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資訊工程學系
With the progress of information technology, digital data is a major trend of business communication today. Therefore, copyright protection of digital data has been an important research issue of information security. In the paper, we proposed an improved visible watermark scheme using multi-parameters adjustable Gamma Correction to reduce the distortion, which can increase color saturation. Our experiments showed that the PSNRs of the stego images with watermark embedded were up to 54.50 dB and 58.66 dB.