• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1296-1302
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• 2016

A hardware implementation of ultra-lightweight block cipher algorithm PRESENT that was specified as a block cipher standard for lightweight cryptography ISO/IEC 29192-2 is described in this paper. Two types of crypto-core that support master key size of 80-bit are designed, one is for encryption-only function, and the other is for encryption and decryption functions. The designed PR80 crypto-cores implement the basic cipher mode of operation ECB (electronic code book), and it can process consecutive blocks of plaintext/ciphertext without reloading master key. The PR80 crypto-cores were designed in soft IP with Verilog HDL, and they were verified using Virtex5 FPGA device. The synthesis results using $0.18{\mu}m$ CMOS cell library show that the encryption-only core has 2,990 GE and the encryption/decryption core has 3,687 GE, so they are very suitable for IoT security applications requiring small gate count. The estimated maximum clock frequency is 500 MHz for the encryption-only core and 444 MHz for the encryption/decryption core.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.91-94
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• 2012

This paper describes an efficient implementation of ARIA crypto algorithm which is a KS (Korea Standards) block cipher algorithm. The ARIA crypto-processor supports three master key lengths of 128/192/256-bit specified in the standard. To reduce hardware complexity, a hardware sharing is employed, which shares round function in encryption/decryption module with key initialization module. It reduces about 20% of gate counts when compared with straightforward implementation. The ARIA crypto-processor is verified by FPGA implementation, and synthesized with a 0.13-${\mu}m$ CMOS cell library. It has 33,218 gates and the estimated throughput is about 640 Mbps at 100 MHz.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.4
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• pp.165-172
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• 2006

In this paper we present a technique for detecting cross-reference points that allows improving watermark detect-ability. In general, Harris detector is commonly used for finding salient points. Harris detector is a kind of combined corner and edge detector which is based on neighboring image data distribution, therefore it has some limitation to find accurate salient points after watermark embedding or any kinds of digital attacks. The new method proposed in this paper used not data distribution but geometrical structure of a normalized image in order to avoid pointing error caused by the distortion of image data. After normalization, we constructed pre-specified number of virtual lines from top to bottom and left to right, and several of cross points were selected by a random key. These selected points specify almost same positions with the accuracy more than that of Harris detector after digital attacks. These points were arranged by a random key, and blocks centered in these points were formed. A reference watermark is formed by a block and embedded in the next block. Because same alteration is applied to the watermark generated and embedded blocks. the detect-ability of watermark is improved even after digital attacks.

• Journal of the Korea Computer Industry Society
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• v.5 no.3
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• pp.405-414
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• 2004

In this paper, we designed a 128-bits block cipher, Circle-g, which has 18-rounds modified Feistel structure and analyzed its secureness by the differential cryptanalysis and linear cryptanalysis. We could have full diffusion effect from the two rounds of the Circle-g. Because of the strong diffusion effect of the F-function of the algorithm, we could get a 9-rounds DC characteristic with probability 2^{-144} and a 12-rounds LC characteristic with probability 2^{-144}. For the Circle-g with 128-bit key, there is no shortcut attack, which is more efficient than the exhaustive key search, for more than 12 rounds of the algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1460-1468
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• 2015

As the number of IoT service increases, the interest of lightweight block cipher algorithm, which consists of simple operations with low-power and high speed, is growing. LEA(Leightweight Encryption Algorithm) is recently adopted as one of lightweight encryption standards in Korea. In this paper a pipeline LEA architecture is proposed to process large amounts of data with high throughput. The proposed pipeline LEA can communicate with external modules in the 32-bit I/O interface. It consists of input, output and encryption pipeline stages which take 4 cycles using a muti-cycle pipeline technique. The experimental results showed that the proposed pipeline LEA achieved more than 7.5 Gbps even though the key length was varied. Compared with the previous high speed LEA in accordance with key length of 128, 192, and 256 bits, the throughput of the pipeline LEA was improved 6.45, 7.52, and 8.6 times. Also the throughput per area was improved 2, 1.82, and 2.1 times better than the previous one.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.1003-1019
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• 2019

Threshold ring signature scheme enables any t entities from N ring members to spontaneously generate a publicly verifiable t-out-of-N signature anonymously. The verifier is convinced that the signature is indeed generated by at least t users from the claimed group, but he cannot tell them apart. Threshold ring signatures are significant for ad-hoc groups such as mobile ad-hoc networks. Based on the lattice-based ring signature proposed by Melchor et al. at AFRICRYPT'13, this work presents a lattice-based threshold ring signature scheme, employing the technique of message block sharing proposed by Choi and Kim. Besides, in order to avoid the system parameter setup problems, we proposed a message processing technique called "pad-then-permute", to pre-process the message before blocking the message, thus making the threshold ring signature scheme more flexible. Our threshold ring signature scheme has several advantages: inherits the quantum immunity from the lattice structure; has considerably short signature and almost no signature size increase with the threshold value; provable to be correct, efficient, indistinguishable source hiding, and unforgeable.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.115-122
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• 2021

In the recent past enormous enterprise applications have migrated into the cloud computing (CC). The researchers have contributed to this ever growing technology and as a result several innovations strengthened to offer the quality of service (QoS) as per the demand of the customer. It was treated that management of resources as the major challenge to offer the QoS while focusing on the trade-offs among the performance, availability, reliability and the cost. Apart from these regular key focuses to meet the QoS other key issues in CC are data integrity, privacy, transparency, security and legal aspects (DIPTSL). This paper aims to carry out the literature survey by reflecting on the prior art of the work with regard to QoS in CC and possible implementation of block chain to implement decentralised CC solutions governing DIPTSL as an integral part of QoS.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.843-850
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• 2006

This is devoted to first, to propose a hash chain algorithm that generates more secure key than conventional encryption method. Secondly, we proposes encryption method that is more secure than conventional system using a encryption method that encrypts each block with each key generated by a hash chain algorithm. Thirdly, After identifying the user via wired and wireless network using a user authentication method. We propose a divided session key method so that Although a client key is disclosed, Attackers cannot catch a complete key and method to safely transfer the key using a divided key method. We make an experiment using various size of digital contents files for performance analysis after performing the design and implementation of system. Proposed system can distribute key securely than conventional system and encrypt data to prevent attacker from decrypting complete data although key may be disclosed. The encryption and decryption time that client system takes to replay video data fie is analogous to the conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.59-64
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• 2012

This paper addresses a blind estimation and classification algorithm of the speech compression methods by using analysis on the structure of compressed bitstreams. Various speech compression methods including vocoders are developed in order to transmit or store the speech signals at very low bitrates. As a key feature, the vocoders contain the block structure inevitably. In classification of each compression method, we use the Measure of Inter-Block Correlation (MIBC) to check whether the bitstream includes the block structure or not, and to estimate the block length. Moreover, for the compression methods with the same block length, the proposed algorithm estimates the corresponding compression method correctly by using that each compression method has different correlation characteristics in each bit location. Experimental results indicate that the proposed algorithm classifies the speech compression methods robustly for various types and lengths of speech signals in noisy environment.

• Journal of Internet Computing and Services
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• v.21 no.3
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• pp.11-19
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• 2020

In this paper, a merged TEA block cipher processor which unifies Tiny Encryption Algorithm(TEA), extended Tiny Encryption Algorithm(XTEA) and corrected block TEA(XXTEA) is designed. After TEA cipher algorithm was first designed, XTEA and XXTEA cipher algorithms were designed to correct security weakness. Three types of cipher algorithm uses a 128-bit master key. The designed cipher processor can encrypt or decrypt 64-bit message block for TEA/XTEA and variable-length message blocks up to 256-bit for XXTEA. The maximum throughput for 64-bit message blocks is 137Mbps and that of 256-bit message blocks is 369Mbps. The merged TEA block cipher designed in this paper has a 16% gain on the area side compared to a lightweight LEA cipher. The cryptographic IP of this paper is applicable in security module of the mobile areas such as smart card, internet banking, and e-commerce.