• SUVANNABHUMI
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• v.6 no.1
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• pp.107-135
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• 2014

Cham identities which are socially constructed and multilayered, display their markers in a variety of elements, including homeland attachment to the former Kingdom of Champa, religion, language and cultural traditions, to mention a few. However, unlike other contemporary diasporic experience which binds the homeland and the host country, the Cham diaspora in Cambodia has a unique pattern as it seems to have no voice in the political and economic spheres in Vietnam, its homeland. The relations between the Cham in Cambodia and Vietnam seem to be limited to cultural heritages such as Cham musical traditions, traditional clothing, and the architectural heritage. Many Cham people have established networks outside Cambodia with areas of the Muslim world, like Malaysia, Indonesia, southern Thailand and the Middle Eastern countries. Pursuing education or training in Islam as well as working in those countries, especially Malaysia has become a way for the Cham to widen their networks and increase their knowledge of particularly, Islam. Returning to Cambodia, these people become religious teachers or ustadz (Islamic teachers in the pondok [Islamic boarding school]). This has developed slowly, side by side with the formation of their identity as Cham Muslims. Among certain Cham, the absence of an ancient cultural heritage as an identity marker has been replaced by the Islamic culture as the important element of identity. However, being Cham is not a single identity, it is fluid and contested. Many scholars argue that the Cham in Cambodia constitute three groups: the Cham Chvea, Cham, and Cham Bani (Cham Jahed). The so-called Cham Jahed has a unique practice of Islam. Unlike other Cham who pray five times a day, Cham Jahed people pray, once a week, on Fridays. They also have a different ritual for the wedding ceremony which they regard as the authentic tradition of the Cham. Indeed, they consider themselves pure descendants of the Cham in Vietnam; retaining Cham traditions and tending to maintain their relationship with their fellow Cham in Central Vietnam. In terms of language, another marker of identity, the Cham and the Cham Jahed share the same language, but Cham Jahed preserve the written Cham script more often than the Cham. Besides, the Cham Jahed teaches the language to the young generation intensively. This paper, based on fieldwork in Cambodia in 2010 and 2011 will focus on the process of the formation of the Cham identity, especially of those called Cham and Cham Jahed.

• Journal of the Korea Society of Computer and Information
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• v.23 no.10
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• pp.111-117
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• 2018

CHAM is a lightweight block cipher, proposed in ICISC 2017. CHAM-n/k has the n-bit block and the k-bit key, and designers recommend CHAM-64/128, CHAM-128/128, and CHAM-128/256. In this paper, we study how to make optimal software implementation of CHAM such that it has high encryption speed on CPUs with high computing power. The best performances of our CHAM implementations are 1.6 cycles/byte for CHAM-64/128, 2.3 cycles/byte for CHAM-128/128, and 3.8 cycles/byte for CHAM-128/256. The comparison with existing software implementation results for well-known block ciphers shows that our results are competitive.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1071-1078
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• 2018

Recently, a family of lightweight block ciphers CHAM that has effective performance on resource-constrained devices is proposed. The CHAM uses a stateless-on-the-fly key schedule method which can reduce the key storage areas. Furthermore, the core design of CHAM is based on ARX(Addition, Rotation and XOR) operations which can enhance the computational performance. Nevertheless, we point out that the CHAM algorithm may be vulnerable to the fault injection attack which can reveal 4 round keys and derive the secret key from them. As a simulation result, the proposed fault injection attack can extract the secret key of CHAM-128/128 block cipher using about 24 correct-faulty cipher text pairs.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.5
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• pp.107-112
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• 2020

Ultra-lightweight password CHAM is an algorithm with efficient addition, rotation and XOR operations on resource constrained devices. CHAM shows high computational performance, especially on IoT platforms. However, lightweight block encryption algorithms used on the Internet of Things may be vulnerable to side channel analysis. In this paper, we demonstrate the vulnerability to side channel attack by attempting a first power analysis attack against CHAM. In addition, a safe algorithm was proposed and implemented by applying a masking technique to safely defend the attack. This implementation implements an efficient and secure CHAM block cipher using the instruction set of an 8-bit AVR processor.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.4
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• pp.709-718
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• 2019

A lightweight block cipher CHAM designed for suitability in resource-constrained environment has reasonable security level and high computational performance. Since this cipher may contain intrinsic weakness on side channel attack, it should adopt a countermeasure such as masking method. In this paper, we implement the masked CHAM cipher on 32-bit microprosessor Cortex-M3 platform to resist against side channel attack and analyze their computational performance. Based on the shortcoming of having many round functions, we apply reduced masking method to the implementation of CHAM cipher. As a result, we show that the CHAM-128/128 algorithm applied reduced masking technique requires additional operations about four times.

• Journal of the Korean Society of Food Culture
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• v.16 no.2
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• pp.180-186
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• 2001

The purpose of this study was to investigate the sensory and physicochemical attributes of Cham-chwi dduk with various amounts of Cham-chwi(Aster scaber) and salt. Cham-chwi dduk was made by steaming glutinous rice flour with Cham-chwi powder for 15 min. Cham-chwi powder was added 1, 3, 5% of glutinous rice flour weight and salt was added 0.5, 1.0 1.5%. According to the sensory evaluation, bitterness and Cham-chwi flavor increased as the amount of Cham-chwi increased and saltiness increased as the amount of salt increased(p<0.05). In the textural profiles, chewiness, adhesiveness, hardness and gumminess were highest when 3% Cham-chwi was added. The moisture content of Cham-chwi dduk was increased as the amount of Cham-chwi was increased and the amount of salt was decreased. The more amount of added Cham-chwi increase, the more green color was strong and yellow color was weak. These results were used to determine the optimum conditions of adding levels of Cham-chwi and salt. Conditions were standardized with minimum range of firmness when expected value of Cham-chwi flavor was more than six and expected value of bitterness was less five. The optimum conditions of Cham-chwi dduk was established as the 3.1% Cham-chwi and 0.6% salt.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.161-164
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• 2020

경량 암호는 컴퓨팅 파워가 부족한 저사양 프로세서를 위해 개발되었다. CHAM은 국산 경량 암호 중 하나로, 세 가지의 규격을 제공하며 ARX 구조를 사용한 암호이다. CHAM 발표 이후, 라운드 수를 조절하여 성능을 향상시킨 Revised CHAM이 제안되었다. 기존 CHAM은 8-bit AVR 프로세서 상에서 최적 구현이 이루어졌지만, 최신 기술인 Revised CHAM은 해당 구현물이 존재하지 않는다. 따라서 8-bit AVR 프로세서를 대상으로 Revised CHAM-64/128을 최적 구현하여 최상의 성능으로 연산이 진행되도록 한다. 본 논문에서는 최적 구현에 사용한 기법들을 소개하며, 기존에 제안된 기법과 성능 비교를 통해 본 기법의 우수함을 서술한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.217-220
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• 2021

ICISC'19에서 기존 CHAM과 동일한 구조와 규격을 갖지만, 라운드 수만 증가시킨 revised CHAM이 발표되었다. CHAM은 사물인터넷에서 사용되는 저사양 프로세서에서 효율적인 구현이 가능한 특징을 갖고 있다. AVR, ARM 프로세서 상에서의 CHAM 암호 알고리즘에 대한 최적 구현은 존재하지만, 아직 RISC-V 프로세서 상에서의 CHAM 구현은 존재하지 않는다. 따라서, 본 논문에서는 RISC-V 프로세서 상에서의 Revised CHAM 알고리즘을 최초로 구현을 제안한다. CHAM 라운드 함수의 내부 구조의 일부를 생략하여 최적 구현하였다. 그리고 홀수 라운드와 짝수 라운드를 모듈별로 구현하여 필요에 따라 모듈을 호출하여 손쉽게 사용할 수 있게 하였다. 결과적으로, RISC-V 상에서 제안 기법 적용하기 전보다 제안 기법 적용 후에 12%의 속도 향상을 달성하였다.

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.1013-1021
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• 2003

Anemia, the condition of the diminished concentration of hemoglobin per erythrocyte is common in patients with cancer and is a frequent complication of myelosuppressive chemotherapy. Cham-Dang-Gui (Angelicae Gigantis Radix) has been used in traditional Korean medicine to treat hematologic deficiencies. In this study, Cyclophosphamide (CYP), an alkylating agent that has a broad spectrum of anti-cancer activities, was intraperitoneally injected into the experimental animals to suppress the bone marrow thereafter, causing anemia. The hemopoietic effects of Cham-Dang-Gui were examined using anemic rat model. Rats were divided into five groups: CON (control group), ANS (CYP-injected + normal diet), AND (CYP-injected + normal diet + Cham-Dang-Gui), ALS (CYP-injected + low iron diet), and ALD (CYP-injected + low iron diet + Cham- Dang-Gui) groups. CYP (30 mg/kg) was intraperitoneally injected to rats for 3 days to induce anemic condition. Saline or Cham-Dang-Gui was administrated orally during the entire experimental period. CYP injection decreased body weight gain and food consumption in comparison with CON group. Oral administration of Cham-Dang-Gui extract with normal iron diet significantly prevented the lower body weight gain. The blood level of hemoglobin, iron status (serum iron, transferrin, ferritin and TIBC) and blood level of vitamin B-12 in Cham-Dang-Gui treated groups were significantly higher than those of Cham-Dang-Gui untreated groups regardless of amount of iron in the diet. Taken together, it could be concluded that the Cham-Dang-Gui extract could improve anemic condition induced by CYP injection by improving hematological value, iron status and vitamin B12 status in rats.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.4
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• pp.629-639
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• 2024

CHAM is designed with an emphasis on encryption speed, considering that in the ISO/IEC standard block cipher operation mode, encryption functions are used more often than decryption functions. In the superscalar architecture of modern general-purpose processors, different ordering of operations can lead to different processing speeds, even if the computation configuration is the same. In this paper, we analyze the implementation efficiency and security of CHAM-like structures, which rearrange the order of operations in the ARX-based block cipher CHAM, for single-block and parallel implementations in a general-purpose processor environment. The proposed structures are at least 9.3% and at most 56.4%efficient in terms of encryption speed. The security analysis evaluates the resistance of the CHAM-like structures to differential and linear attacks. In terms of security margin, the difference is 3.4% for differential attacks and 6.8%for linear attacks, indicating that the security strength is similar compared to the efficiency difference. These results can be utilized in the design of ARX-based block ciphers.