• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.6
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• pp.35-44
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• 2011

The PP-1/64-128 block cipher support variety data block and secret key size. Also, it is suitable for hardware implementation and can much easier to apply Concurrent Error Detection(CED) for cryptographic chips compared to other block ciphers, because it has same encryption and decryption process. In this paper, we proposed truncated differential cryptanalysis of PP-1/64-128. the attack on PP-1/64-128 block cipher requires $2^{50.16}$ chosen plaintexts, $2^{46.16}$ bytes memory spaces and $2^{50.45}$ PP-1/64-128 encryption to retrieve secret key. This is the best result of currently known PP-1/64-128 differential cryptanalysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.2
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• pp.57-72
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• 2010

Hash based RFID protocols proposed by Ha and M.Burmester is a scheme that tag's ID is updated using hash function to provide forward secrecy after session end. But this protocols have a problem both privacy and efficiency. This paper analyze a problem for privacy to apply a privacy game model proposed by Vaudenay. we analyze the cause that these scheme is difficult with tag's cheap implementation and efficient resynchronization. To solve these problems, we proposed a new hash based mutual authentication protocol which apply only two protocol's advantages. this protocols is based of resynchronization algorithm for Ha et al.'s protocol and added a new simple counter to record the numner of continuous desynchronization between tag and reader secret informations. this counter is more simple than cyclic counter proposed by M. Burmester's protocol. Also, we prove that proposal protocol improve a privacy against a privacy attack which is executed for Ha and M. Burmester's protocols.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.121-134
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• 2010

With the help of various Layer 2 triggers, Fast Handover for Mobile IPv6 (FMIPv6) considerably reduces the latency and the signaling messages incurred by the handover. Obviously, if not secured, the protocol is exposed to various security threats and attacks. In order to protect FMIPv6, several security protocols have been proposed. To our best knowledge, there is lack of analysis and comparison study on them though the security in FMIPv6 is recognized to be important. Motivated by this, we provide an overview of the security protocols for FMIPv6, followed by the comparison analysis on them. Also, the security threats and requirements are outlined before the protocols are explored. The comparison analysis result shows that the protocol presented by You, Sakurai and Hori is more secure than others while not resulting in high computation overhead. Finally, we introduce Proxy MIPv6 and its fast handover enhancements, then emphasizing the need for a proper security mechanism for them as a future work.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.481-496
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• 2021

It is imperative to migrate the current public key cryptosystem to a quantum-resistance system ahead of the realization of large-scale quantum computing technology. The National Institute of Standards and Technology, NIST, is promoting a public standardization project for Post-Quantum Cryptography(PQC) and also many research efforts have been conducted to apply PQC to TLS(Transport Layer Security) protocols, which are used for Internet communication security. In this paper, we propose a scenario in which a server and multi-clients share session keys on TLS by using the parallelized NTRU which is PQC in the key exchange process. In addition, we propose a method of accelerating NTRU using GPU and analyze its efficiency in an environment where a server needs to process large-scale data simultaneously.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.533-544
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• 2021

Using Shor algorithm, factoring and discrete logarithm problem can be solved effectively. The public key cryptography, such as RSA and ECC, based on factoring and discrete logarithm problem can be broken in polynomial time using Shor algorithm. NIST has been conducting a PQC(Post Quantum Cryptography) standardization process to select quantum-resistant public key cryptography. The multivariate quadratic based signature scheme, which is one of the PQC candidates, is suitable for IoT devices with limited resources due to its short signature and fast sign and verify process. We analyzes classic attacks and quantum attacks for Rainbow which is the only multivatiate quadratic based signature scheme to be finalized up to the round 3. Also we compute the attack complexity for the round 3 Rainbow parameters, and analyzes the security level of Rainbow, one of the PQC standardization candidates.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.251-258
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• 2021

In this paper, we proposed an encoder-decoder model utilizing residual learning to improve the accuracy of the U-Net-based semantic segmentation method. U-Net is a deep learning-based semantic segmentation method and is mainly used in applications such as autonomous vehicles and medical image analysis. The conventional U-Net occurs loss in feature compression process due to the shallow structure of the encoder. The loss of features causes a lack of context information necessary for classifying objects and has a problem of reducing segmentation accuracy. To improve this, The proposed method efficiently extracted context information through an encoder using residual learning, which is effective in preventing feature loss and gradient vanishing problems in the conventional U-Net. Furthermore, we reduced down-sampling operations in the encoder to reduce the loss of spatial information included in the feature maps. The proposed method showed an improved segmentation result of about 12% compared to the conventional U-Net in the Cityscapes dataset experiment.

• Journal of Internet Computing and Services
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• v.22 no.3
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• pp.1-8
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• 2021

Ultra high-quality and ultra high-resolution omnidirectional 360-degree video streaming is needed to provide immersive media through head-mounted display(HMD) in virtual reality environment, which requires high bandwidth and computational complexity. One of the approaches avoiding these problems is to apply viewport-dependent selective streaming using tile-based segmentation method. This paper presents a performance analysis of viewport-dependent tiled streaming on 16K ultra high-quality 360-degree videos and 4K 360-degree videos which are widely used. Experimental results showed 42.47% of bjotegaard delta rate(BD-rate) saving on 16K ultra high-quality 360-degree video tiled streaming compared to viewport-independent streaming while 4K 360-degree video showed 26.41% of BD-rate saving. Therefore, this paper verified that tiled streaming is more efficient on ultra-high quality video.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.123-127
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• 2021

Millimeter-wave tracking radars should be operated in various environmental restrictions, thus they demand more computing power and smaller size compared to conventional tracking radars. This paper presents the design and implementation of the compact power supply for millimeter-wave tracking radar applications. To meet requirements of low voltage/high current and voltage accuracy for FPGA/DSP digital circuits, Point of Load (POL) converters are used in order to enhance power density and system efficiency. LDO (Low Dropout) is applied for the output voltage under the light load condition, then the single-input-multi-output power supply with max power of 375 W and 8 outputs is developed. The proposed power supply achieves output voltage accuracy of ±2 % and noise level of <50 mVpp % under full load conditions.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.356-365
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• 2021

The nationwide expansion of the agricultural early warning service for agrometeorological disaster would require assessment of geographical and agricultural environmental characteristics by individual region. The development of an efficient computing environment would facilitate such services for the area of study region to deal with various crops and varieties for many farms. In particular, the design of the computing environment would have a considerable impact on the service quality of agriculture meteorology when the scale of computing environments increases for extended service areas. The objectives of this study were to derive the issues on the current computing environment under which services are provided by each region and to seek the solutions to these problems. The self-evaluation through experimental operation for about a year indicated that integration of the early warning service system distributed over different regions would reduce redundant computing procedures and ensure efficient storage and comprehensive management of data. This suggested that the early warning service for agrometeorological disaster would become more stable even when the service areas are to be expanded to the national scale. This would contribute to higher quality services for individual farmers.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.313-330
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• 2021

In an autonomous driving system equipped with a camera and lidar, depth completion techniques enable dense depth estimation. In particular, using self-supervised learning it is possible to train the depth completion network even without ground truth. In actual autonomous driving, such depth completion should have very short latency as it is the input of other algorithms. So, rather than complicate the network structure to increase the accuracy like previous studies, this paper focuses on network latency. We design a U-Net type network with RegNet encoders optimized for GPU computation. Instead, this paper presents several techniques that can increase accuracy during the process of self-supervised learning. The proposed techniques increase the robustness to unreliable lidar inputs. Also, they improve the depth quality for edge and sky regions based on the semantic information extracted in advance. Our experiments confirm that our model is very lightweight (2.42 ms at 1280x480) but resistant to noise and has qualities close to the latest studies.