• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.183-191
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• 2023

Cryptographic algorithms require extensive computational resources and rely on complex mathematical principles for security. However, IoT devices have limited resources, leading to insufficient computing power. As a result, lightweight cryptography has emerged, which uses fewer computational resources. NIST organized a competition to standardize lightweight cryptography and TinyJAMBU, one of the algorithms in the competition, is a permutation-based algorithm that repeats many permutation operations. In this paper, we implement TinyJAMBU on an 8-bit AVR processor with a proposedtechnique that includes a reverse shift method and precomputing some operations in a fixed key and nonce environment. Our techniques showed a maximum performance improvement of 7.03 times in permutation operations and 5.87 times in the TinyJAMBU algorithm, improving up to 9.19 times in a fixed key and nonce environment.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.101-110
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• 2009

The 6LoWPAN(IPv6 Low-power Wireless Personal Area Network) performs IPv6 header compression, TCP/UDP/IGMP header compression, packet fragmentation and re-assemble to transmit IPv6 packet over IEEE 802,15.4 MAC/PHY. However, from the point of view of security. It has the existing security threats issued by IP packet fragmenting and reassembling, and new security threats issued by 6LoWPAN packet fragmenting and reassembling would be introduced additionally. If fragmented packets are retransmitted by replay attacks frequently, sensor nodes will be confronted with the communication disruption. This paper analysis security threats introduced by 6LoWPAN fragmenting and reassembling, and proposes a re-transmission mechanism that could minimize re-transmission to be issued by replay attacks. Re-transmission procedure and fragmented packet structure based on the 6LoWPAN standard(RFC4944) are designed. We estimate also re-transmission delay of the proposed mechanism. The mechanism utilizes timestamp, nonce, and checksum to protect replay attacks. It could minimize reassemble buffer overflow, waste of computing resource, node rebooting etc., by removing packet fragmentation and reassemble unnecessary.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.40-42
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• 2005

최근 XML을 기반으로 한 웹서비스는 인터넷 전자상거래와 인터넷을 기반으로 한 서비스통합 등 다양한 분야에서 활용되고 있으며 웹서비스를 이용한 메시지 및 문서를 안전하게 송수신 하기위해 XKMS기반 하에 XML전자서명, XML암호화 등이 표준화 되어 있다. 그러나 웹서비스를 위한 XML기반 PKI서비스인 XKMS는 PKI와의 연동방안이 제시되어 있지 않으며 PKI와 XKMS간의 상호인증이 보장되어 있지 않고 서비스거부공격과 재연공격 등에 취약점이 있는 등 여러 가지 취약점이 분석되고 있다. 본 논문에서는 CA발행 공인인증서를 활용한 XKMS와 PKI서버간의 상호인증방안을 제시하고 메시지 송수신 시 nonce값을 이용하여 재연공격을 방지할 수 있는 메시지 형식을 정의함으로써 보다 안전하게 XKMS PKI가 연동을 하는데 도움이 되고자 한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.256-259
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• 2003

This paper presents mutual authentication scheme between user and network on mobile communications using public key scheme based on counter, and simultaneously shows key agreement between user and user using random number for secure communications. This is also a range of possible solutions to authentication and key agreement problem-authentication and key agreement protocol based on nonce and count, and secure end-to-end protocol based on the function Y=f(.)$\^$1/, C$\^$i/ is count of user I, and f(.) is one way function.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5596-5615
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• 2016

Security is one of the major challenges in the Wireless Sensor Networks (WSNs). WSNs are more vulnerable to adversarial activities. All cryptographic security services indirectly depend on key management. Symmetric key management is the best key establishment process for WSNs due to the resource constraints of the sensors. In this paper, we proposed dynamic session key establishment scheme based on randomly generated nonce value and sensor node identity, in which each sensor node is equipped with session key on expire basis. The proposed scheme is compare with five popular existing key management systems. Our scheme is simulated in OMNET++ with MixiM and presented experimental results. The analytical study and experimental results show the superiority of the proposed scheme over the existing schemes in terms of energy, storage, resilience and communication overhead.

• ETRI Journal
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• v.32 no.1
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• pp.93-101
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• 2010

A true random number generator (TRNG) is widely used to generate secure random numbers for encryption, digital signatures, authentication, and so on in crypto-systems. Since TRNG is vulnerable to environmental changes, a deterministic function is normally used to reduce bias and improve the statistical properties of the TRNG output. In this paper, we propose a linear corrector for secure TRNG. The performance of a linear corrector is bounded by the minimum distance of the corresponding linear error correcting code. However, we show that it is possible to construct a linear corrector overcoming the minimum distance limitation. The proposed linear corrector shows better performance in terms of removing bias in that it can enlarge the acceptable bias range of the raw TRNG output. Moreover, it is possible to efficiently implement this linear corrector using only XOR gates, which must have a suitable hardware size for embedded security systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4060-4075
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• 2019

ACORN is an authenticated encryption algorithm proposed as a candidate in the currently ongoing CAESAR competition. ACORN has a good performance on security and efficiency which has been a third-round candidate. This paper mainly concentrates on the security of ACORN under the forgery attack and the non-repudiation of ACORN. Firstly, we analyze the differential properties of the feedback function in ACRON are analyzed. By taking advantage of these properties, the forgery attacks on round-reduced ACORN are proposed with a success probability higher than $2^{-128}$ when the number of finalization rounds is less than 87. Moreover, the non-repudiation of ACRON in the nonce-reuse setting is analyzed. The known collision can be used to deny the authenticated message with probability $2^{-120}$. This paper demonstrates that ACORN cannot generate the non-repudiation completely. We believe it is an undesirable property indeed.

• Phonetics and Speech Sciences
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• v.10 no.4
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• pp.101-110
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• 2018

This study aimed to show that Selkirk's concept of resyllabification offers a better analysis than Kahn's ambisyllabification to account for phonetic resyllabification. We conducted two production experiments to investigate the acoustic characteristics of the English /s/ in real words and nonce words. Ten English native speakers and six English native speakers participated in experiment 1 and experiment 2, respectively. Three acoustic cues - frication duration, center of gravity and aspiration duration of word-medial /s/ - were measured. We found that these three cues of the word-medial /s/ were realized significantly differently depending on the stresshood and openness of the preceding syllable. We preferred Selkirk's resyllabification to Kahn's ambisyllabification to explain this result because the word-medial and intervocalic /s/ behaved as the coda (as opposed to the onset) when the preceding syllable was stressed and open. The result thus suggested that two conditions must be met for the resyllabification rule to apply in English: a word-medial consonant is resyllabified only when its preceding syllable is stressed and open.

• Phonetics and Speech Sciences
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• v.10 no.4
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• pp.11-17
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• 2018

This study reports on a production experiment designed to investigate how Korean speaking learners of English produce English forms ending in stops. In a repetition experiment, Korean participants listened to English nonce words ending in a stop and repeated what they heard. English speakers were recruited for the same task as a control group. The experimental result indicated that the transcriptions of the Korean productions by English native speakers showed vowel insertion in only 3% of productions although the pronunciation of English final stops showed that noise intervals after the closure of final stops were significantly longer for Korean speakers than for English speakers. This finding is inconsistent with the loanword data where 49% of words showed vowel insertion. It is also not compatible with the perceptual similarity approach, which predicts that because Korean speakers accurately perceive an English final stop as a final consonant, they will insert a vowel to make the English sound more similar to the Korean sound.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.6161-6176
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• 2018

Pseudorandom numbers are useful in cryptographic operations for using as nonce, initial vector, secret key, etc. Security of the cryptosystem relies on the secret key parameters, so a good pseudorandom number is needed. In this paper, we have proposed a new approach for generation of pseudorandom number. This method uses the three dimensional combinational puzzle Rubik Cube for generation of random numbers. The number of possible combinations of the cube approximates to 43 quintillion. The large possible combination of the cube increases the complexity of brute force attack on the generator. The generator uses cryptographic hash function. Chaotic map is being employed for increasing random behavior. The pseudorandom sequence generated can be used for cryptographic applications. The generated sequences are tested for randomness using NIST Statistical Test Suite and other testing methods. The result of the tests and analysis proves that the generated sequences are random.