• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.476-487
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• 2016

Although the number of adolescents with complicated problems and needs has increased, there has been a limited service for this population. In addition, a traditional social service could not alleviate the problems. In order to provide an alternative to a traditional social service to this population, the wraparound model is reviewed and explored. The study presents a review of literature on wraparound and social work via EBSOCO. By reviewing 12 articles on the subject, the study discovers 3 topics, such as (1) youth with various problems, (2) general characteristics of wraparound, and (3) evidence-based practice and wraparound. Based on 3 topics, the study also discusses the feasibility of wraparound service in Korea.

• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.147-155
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• 2005

For the last several decades, many researches have been performed to distribute bandwidth fairly between sessions. In this problem, the most important challenge is to realize a scalable implementation and high fairness simultaneously. Here high fairness means that bandwidth is distributed fairly even in short time intervals. Unfortunately, existing scheduling algorithms either are lack of scalable implementation or can achieve low fairness. In this paper, we propose a scheduling algorithm that can achieve feasible fairness without losing scalability. The proposed algorithm is a Hierarchical Deficit Round-Robin (H-DRR). While H-DRR requires a constant time for implementation, the achievable fairness is similar to that of Packet-by-Packet Generalized Processor Sharing(PGPS) algorithm. PGPS has worse scalability since it uses a sorted-priority queue requiring O(log N) implementation complexity where N is the number of sessions.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.21-30
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• 2002

Nowadays the fair queuing field is studied actively for solving the unfair queuing problem which degrades the service performance of various applications on network. Above all DRR is a scheme that has lower work complexity and can be implemented easily. It guarantees the fair service by serving each queue every round Service Quantum(SQ) that includes the service deficit of the previous round. But it increases the delay by the numbers of unnecessary resetting of SQ or round circulation for the service that have the packet size over maximum several kbyte. In this paper, We propose the method that sets SQ dynamically to minimize this problem and the method that minimizes the work complexity on processing of packet. The proposed scheme minimizes the delay on various applications in enterprise environment by setting SQ dynamically and processing the packet simply.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1379-1392
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• 2018

The complexity of the differential-linear cryptanalysis is strongly influenced by the probability of the differential-linear characteristic computed under the assumption of round independence, linear approximation independence, and uniformity for the trail that does not satisfy differential trail. Therefore, computing the exact probability of the differential-linear characteristic is a very important issue related to the validity of the attack. In this paper, we propose a new concept called DLCT(Differential-Linear Connectivity Table) for the differential-linear cryptanalysis. Additionally, we propose an improved probability computation technique of differential-linear characteristic by applying DLCT. By doing so, we were able to weaken linear approximation independence assumption. We reanalyzed the previous results by applying DLCT to DES and SERPENT. The probability of 7-round differential-linear characteristic of DES is $1/2+2^{-5.81}$, the probability of 9-round differential-linear characteristic of SERPENT is computed again to $1/2+2^{-57.9}$, and data complexity required for the attack is reduced by $2^{0.2}$ and $2^{2.2}$ times, respectively.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.110-118
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• 2006

Cryptographic protocol design in a two-party setting has of tel ignored the possibility of simultaneous message transmission by each of the two parties (i.e., using a duplex channel). In particular, most protocols for two-party key exchange have been designed assuming that parties alternate sending their messages (i.e., assuming a bidirectional half-duplex channel). However, by taking advantage of the communication characteristics of the network it may be possible to design protocols with improved latency. This is the focus of the present work. We present three provably-secure protocols for two-party authenticated key exchange (AKE) which require only a single round. Our first, most efficient protocol provides key independence but not forward secrecy. Our second scheme additionally provides forward secrecy but requires some additional computation. Security of these two protocols is analyzed in the random oracle model. Our final protocol provides the same strong security guarantees as our second protocol, but is proven secure in the standard model. This scheme is only slightly less efficient (from a computational perspective) than the previous ones. Our work provides the first provably- secure one-round protocols for two-party AKE which achieve forward secrecy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.3
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• pp.3-10
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• 2009

In this paper, we introduce improved differential and linear attacks on the SMS4 block cipher which is used in the Chinese national standard WAPI (WLAN Authentication and Privacy Infrastructure, WLAN - Wireless Local Area Network): First, we introduce how to extend previously known differential attacks on SMS4 from 20 or 21 to 22 out of the full 32 rounds. Second, we improve a previously known linear attack on 22-round reduced SMS4 from $2^{119}$ known plaintexts, $2^{109}$ memory bytes, $2^{117}$ encryptions to $2^{117}$ known plaintexts, $2^{l09}$ memory bytes, $2^{112.24}$ encryptions, by using a new linear approximation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.175-182
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• 2023

Differential cryptanalysis is one of the analysis techniques for block ciphers, and uses the property that the output difference with respect to the input difference exists with a high probability. If random data and differential data can be distinguished, data complexity for differential cryptanalysis can be reduced. For this, many studies on deep learning-based neural distinguisher have been conducted. In this paper, a deep learning-based neural distinguisher for PIPO 64/128 is proposed. As a result of experiments with various input differences, the 3-round neural distinguisher for the differential characteristics for 0, 1, 3, and 5-rounds achieved accuracies of 0.71, 0.64, 0.62, and 0.64, respectively. This work allows distinguishing attacks for up to 8 rounds when used with the classical distinguisher. Therefore, scalability was achieved by finding a distinguisher that could handle the differential of each round. To improve performance, we plan to apply various neural network structures to construct an optimal neural network, and implement a neural distinguisher that can use related key differential or process multiple input differences simultaneously.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.467-476
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• 2017

In this paper, we analyze Generalized Feistel Network(GFN) Type I, Type II, Type III that round function use SP update function, secret S-box and $k{\times}k$ MDS matirx. In this case an attacker has no advantage about S-box. For each type of GFN, we analyze and restore secret S-box in 9, 6, 6 round using the basis of integral cryptanalysis with chosen plaintext attack. Also we restore secret S-box in 16 round of GFN Type I with chosen ciphertext attack. In conclusion, we need $2^{2m}$ data complexity and ${\frac{2^{3m}}{32k}},{\frac{2^{3m}}{24k}},{\frac{2^{3m}}{36k}}$ time complexity to restore m bit secret S-box in GFN Type I, Type II, Type III.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.644-652
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• 2009

New communication environments such as USN, WiBro and RFID have been realized nowadays. Thus, in order to ensure security and privacy protection, various light-weight block ciphers, e.g., mCrypton, HIGHT, SEA and PRESENT, have been proposed. The block cipher mCrypton, which is a light-weight version of Crypton, is a 64-bit block cipher with three key size options (64 bits, 96 bits, 128 bits). In this paper we show that 8-round mCrypton with 128-bit key is vulnerable to related-key rectangle attack. It is the first known cryptanalytic result on mCrypton. We first describe how to construct two related-key truncated differentials on which 7-round related-key rectangle distinguisher is based and then exploit it to attack 8-round mCrypton. This attack requires $2^{45.5}$dada and $2^{45.5}$time complexities which is faster than exhaustive key search.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.4
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• pp.607-615
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• 2022

The SITM (See-In-The-Middle) proposed in CHES 2020 is a methodology for side-channel assisted differential cryptanalysis. This technique analyzes the power traces of unmasked middle rounds in partial masked SPN block cipher implementation, and performs differential analysis with the side channel information. Blockcipher GIFT is a lightweight blockcipher proposed in CHES 2017, designed to correct the well-known weaknesses of block cipher PRESENT and provide the efficient implementation. In this paper, we propose SITM attacks on partial masked implementation of GIFT-128. This attack targets 4-round and 6-round masked implementation of GIFT-128 and time/data complexity is 2^14.01 /2^14.01, 2¹⁶ /2¹⁶. In this paper, we compare the masterkey recovery logic available in SITM attacks, establishing a criterion for selecting more efficient logic depending on the situation. Finally, We introduce how to apply the this attack to GIFT-COFB, one of the finalist candidates in NIST lightweight cryptography standardization process.