• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.106-109
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• 2002

무선 통신의 발달로 무선 단말기 상에서 서명 생성 및 검증과 메시지의 암호화와 복호화 등의 연산의 필요성이 대두되었다. 하지만, 무선 통신이라는 특성상 적은 메모리 용량을 사용해서 빠른 연산을 수행하고, 적은 통신량을 보장해야 한다. 이러한 무선 단말기의 제약사항은 서명과 암호화를 함께 하는 Signcryption 개념과 ECC 기반의 연산을 수행하여 해결할 수 있다. 또한 네트워크상에서의 정보보안을 위해 설치된 방화벽을 통과하기 위해서는 서명의 검증이 필요한데, 서명된 메시지를 암호화 해서 보낼 경우 서명 검증시 수신자의 비밀키가 있어야 메시지를 복원해서 서명을 검증할 수 있기 때문에 이 점을 보완하기 위해 본 논문에서는 서명 검증시에 평문이 필요없는 ECC 기반의 signcryption 방식을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4527-4547
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• 2018

Signcryption is a cryptographic primitive that provides authentication (signing) and confidentiality (encrypting) simultaneously at a lower computational cost and communication overhead. With the proposition of certificateless public key cryptography (CLPKC), certificateless signcryption (CLSC) scheme has gradually become a research hotspot and attracted extensive attentions. However, many of previous CLSC schemes are constructed based on time-consuming pairing operation, which is impractical for mobile devices with limited computation ability and battery capacity. Although researchers have proposed pairing-free CLSC schemes to solve the issue of efficiency, many of them are in fact still insecure. Therefore, the challenging problem is to keep the balance between efficiency and security in CLSC schemes. In this paper, several existing CLSC schemes are cryptanalyzed and a new CLSC scheme without pairing based on elliptic curve cryptosystem (ECC) is presented. The proposed CLSC scheme is provably secure against indistinguishability under adaptive chosen-ciphertext attack (IND-CCA2) and existential unforgeability under adaptive chosen-message attack (EUF-CMA) resting on Gap Diffie-Hellman (GDH) assumption and discrete logarithm problem in the random oracle model. Furthermore, the proposed scheme resists the ephemeral secret leakage (ESL) attack, public key replacement (PKR) attack, malicious but passive KGC (MPK) attack, and presents efficient computational overhead compared with the existing related CLSC schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.455-472
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• 2020

As a user in modern societies with the rapid growth of Internet environment and more complicated business flow processes in order to be effective at work and accomplish things on time when the manager of the company went for a business trip, he/she need to delegate his/her signing authorities to someone such that, the delegatee can act as a manager and sign a message on his/her behalf. In order to make the delegation process more secure and authentic, we proposed a secure and efficient identity-based proxy signcryption in cloud data sharing (SE-IDPSC-CS), which provides a secure privilege delegation mechanism for a person to delegate his/her signcryption privilege to his/her proxy agent. Our scheme allows the manager of the company to delegate his/her signcryption privilege to his/her proxy agent and the proxy agent can act as a manager and generate signcrypted messages on his/her behalf using special information called "proxy key". Then, the proxy agent uploads the signcrypted ciphertext to a cloud service provider (CSP) which can only be downloaded, decrypted and verified by an authorized user at any time from any place through the Internet. Finally, the security analysis and experiment result determine that the proposed scheme outperforms previous works in terms of functionalities and computational time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2512-2529
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• 2015

Wireless mesh networks (WMNs) provide an efficient and flexible method to the field of wireless networking, but also bring many security issues. A mesh point may lose all of its available links during its movement. Thus, the mesh point needs to handover to a new mesh point in order to obtain access to the network again. For multi-domain WMNs, we proposed a new ID-based signcryption scheme and accordingly present a novel ID-based handover protocol for mesh points. The mutual authentication and key establishment of two mesh points which belong to different trust domains can be achieved by using a single one-round message exchange during the authentication phase. The authentication server is not involved in our handover authentication protocol so that mutual authentication can be completed directly by the mesh points. Meanwhile, the data transmitted between the two mesh points can be carried by the authentication messages. Moreover, there are no restrictions on the PKG system parameters in our proposed multi-domain ID-based signcryption scheme so our handover scheme can be easily applied to real WMNs circumstances. Security of the signcryption scheme is proved in the random oracle model. It shows that our protocol satisfies the basic security requirements and is resistant to existing attacks based on the security of the signcryption. The analysis of the performance demonstrates that the protocol is efficient and suitable for the multi-domain WMNs environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.129-136
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• 2003

A representative payment broker system is SET and one of its signature shcemes is a dual digital signature scheme. A dual digital signature scheme expose neither user's payment information(credit card number etc.) to merchandiser, nor user's order information to bank So it keeps user's Privacy safe. The digital signature scheme like this is being necessary as E-commerce is revitalized. But a dual digital signature of SET is not appropriate for wireless environments because it needs so many computations and communications. In this paper, we propose a signcryption scheme that generates a polynomial using a payment information for merchandiser and an order information for bank in order to reduce communications. We analyze the problem of existing signcryption schemes and dual digital signature schemes. Also we analyze the security properties of the proposed scheme.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.344-348
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• 2006

현재 PGP(Pretty Good Privacy)와 S/MIME(Secure/Multipurpose Internet Mail Extension)와 같은 여러 가지 이메일 보안 프로토콜들이 제안되어 사용되고 있으나 이들 프로토콜은 최근 중요시되고 있는 보안 요구사항인 전방향 안전성을 보장하지 못한다. 최근에 이 요구사항을 충족하는 이메일 보안 프로토콜들이 제안되었으나 현실적이지 못한 가정 하에 설계되었거나 효율성 측면에서 개선이 필요한 프로토콜들이다. 또한 일부 프로토콜들은 실제 완전한 전방향 안전성을 제공하지 못하고 있다. 이 논문에서는 이 부분을 개선하고, 완전한 전방향 안전성을 제공하는 안전한 이메일 프로토콜을 제안한다. 제안되는 프로토콜은 Zheng 의 signcryption 기법을 사용하여 효율적이고 안전한 인증을 제공한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2940-2955
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• 2012

In this paper, we propose aggregate signcryption for achieving data security in UWSNs. The main challenge of these networks established in sensitive environments is offline sink visiting. Moreover, the sensors must retain collected data for long enough time to offload them onto the itinerant sink. Thus, the unattended nature of data collection intervals might offer the adversary the opportunity to apply various attacks without detection. In this paper, employing low order operations (in time and space), we propose a new secure scheme in which various security goals such as confidentiality (through encrypting), authentication and integrity (through signing) are achieved. In addition, the aggregation process of our scheme reduces the space and communication overheads both for sensors and sink, i.e. the proposed technique efficiently enables the sensors and sink to protect, verify and recover all the related data. We further compare our scheme with the best alternative work in the literature.

• ETRI Journal
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• v.34 no.3
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• pp.421-428
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• 2012

An aggregate signature scheme is a digital signature scheme that allows aggregation of n distinct signatures by n distinct users on n distinct messages. In this paper, we present an aggregate signcryption scheme (ASC) that is useful for reducing the size of certification chains (by aggregating all signatures in the chain) and for reducing message size in secure routing protocols. The new ASC scheme combines identity-based encryption and the aggregation of signatures in a practical way that can simultaneously satisfy the security requirements for confidentiality and authentication. We formally prove the security of the new scheme in a random oracle model with respect to security properties IND-CCA2, AUTH-CMA2, and EUF-CMA.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.439-441
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• 2002

Real-time Transport Protocol (RTP) is widely used in VoIP stacks charging the multimedia data delivery. Concerning with payload protection of RTP packets, Secure RTP has been discussed in IETF AVT group to provide confidentiality and authentication features using block ciphering and message authentication coding. However, Secure RTP only concentrates on payload protection. Signcryption is a good candidate for key agreement. This paper proposes a key establishment protocol using Signcryption and shows example implementation of a secure VoIP application based on Secure RTP with the proposed scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.344-365
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• 2020

Providing security has been always on priority in all areas of computing and communication, and for the systems that are low on computing power, implementing appropriate and efficient security mechanism has been a continuous challenge for the researchers. Radio Frequency Identification (RFID) system is such an environment, which requires the design and implementation of efficient security mechanism. Earlier, the security protocols for RFID based on hash functions and symmetric key cryptography have been proposed. But, due to high strength and requirement of less key size in elliptic curve cryptography, the focus of researchers has been on designing efficient security protocol for RFID based on elliptic curves. In this paper, an efficient elliptic curve signcryption based security protocol for RFID has been proposed, which provides mutual authentication, confidentiality, non-repudiation, integrity, availability, forward security, anonymity, and scalability. Moreover, the proposed protocol successfully provides resistance from replay attack, impersonation attack, location tracking attack, de-synchronization attack, denial of service attack, man-in-the-middle attack, cloning attack, and key-compromise attack. Results have revealed that the proposed protocol is efficient than the other related protocols as it takes less computational time and storage cost, especially for the tag, making it ideal to be used for RFID systems.