• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.1-13
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• 2008

Trusted Computing is a hardware-based technology that aims to guarantee security for machines beyond their users' control by providing security on computing hardware and software. TPM(Trusted Platform Module), the trusted platform specified by the Trusted Computing Group, acts as the roots for the trusted data storage and the trusted reporting of platform configuration. Data sealing encrypts secret data with a key and the platform's configuration at the time of encryption. In contrast to the traditional data sealing based on binary hash values of the platform configuration, a new approach called property-based data sealing was recently suggested. In this paper, we propose and analyze a new property-based data sealing protocol using the weakest precondition concept by Dijkstra. The proposed protocol resolves the problem of system updates by allowing sealed data to be unsealed at any configuration providing the required property. It assumes practically implementable trusted third parties only and protects platform's privacy when communicating. We demonstrate the proposed protocol's operability with any TPM chip by implementing and running the protocol on a software TPM emulator by Strasser. The proposed scheme can be deployed in PDAs and smart phones over wireless mobile networks as well as desktop PCs.

• The KIPS Transactions:PartC
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• v.16C no.3
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• pp.335-346
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• 2009

Mobile environments are evolving the main communication environment as a develops of communication technology. In mobile environments, sensitive information can be compromised on-line, so demand for security has increased. Also, mobile devices that provide various services are in danger from malware and illegal devices, phishing and sniffing etc, and the privacy. Therefore, MTM(Mobile Trusted Module) is developed and promoted by TCG(Trusted Computing Group), which is an industry standard body to enhance the security level in the mobile computing environment. MTM protects user privacy and platform integrity, because it is embedded in the platform, and it is physically secure. However, a security approach is required when secret data is migrated elsewhere, because MTM provides strong security functions. In this paper, we analyze the TCG standard and migration method for cryptographic key, then we propose a secure migration scheme for cryptographic key using key Backup/Recovery method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5529-5552
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• 2016

Mobile cloud computing (MCC) has revolutionized the way in which the services can be obtained from the cloud service providers. Manifold increase in the number of mobile devices and subscribers in MCC has further enhanced the need of an efficient and robust authentication solution. Earlier, the subscribers could get cloud-computing services from the cloud service providers only after having consulted the trusted third party. Recently, Tsai and Lo has proposed a multi-server authenticated key agreement solution for MCC based on bilinear pairing, to eliminate the trusted third party for mutual authentication. The scheme has been novel as far as the minimization of trusted party involvement in authenticating the user and service provider, is concerned. However, the Tsai and Lo scheme has been found vulnerable to server spoofing attack (misrepresentation attack), de-synchronization attack and denial-of-service attack, which renders the scheme unsuitable for practical deployment in different wireless mobile access networks. Therefore, we have proposed an improved model based on bilinear pairing, countering the identified threats posed to Tsai and Lo scheme. Besides, the proposed work also demonstrates performance evaluation and formal security analysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.545-558
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• 2021

Recently, Confidential computing plays an important role in next-generation cloud technology along with the development of trusted execution environments(TEEs), as it guarantees the trustworthiness of applications despite of untrusted nature of the cloud. Both academia and industry have actively proposed commercialized confidential computing solutions based on Intel SGX technology. However, the lack of clear criteria makes developers difficult to select a proper confidential computing framework among the possible options when implementing TEE-based cloud applications. In this paper, we derive baseline metrics that help to clarify the pros and cons of each framework through in-depth comparative analysis against existing confidential computing frameworks. Based on the comparison, we propose criteria to application developers for effectively selecting an appropriate confidential computing framework according to the design purpose of TEE-based applications.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.79-91
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• 2008

Modern society as an information society, a lot of information is communicated in on-line. Specially, mobile environment based on radio communication has a characteristic of flexibility compared with wire communication and is developed rapidly. However, the more mobile technology is developed the more security for sensitive information is needed. Therefore, MTM(Mobile Trusted Module) is developed and promoted by TCG(Trusted Computing Group), which is an industry standard body to enhance the security level in the mobile computing environment. MTM, hardware security module for mobile environment, offers user's privacy protection, platform integrity verification, and individual platform attestation. On the other hand, secure migration scheme is required in case secret data or key is transferred from one platform to the other platform. In this paper, we analyze migration schemes which were described in TCG standard and other papers and then propose security maintenance scheme for secret data using USIM(Universal Subscriber Identity Module).

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.282-296
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• 2013

With the emergence of cloud computing, more and more sensitive user data are outsourced to remote storage servers. The privacy of users' access pattern to the data should be protected to prevent un-trusted storage servers from inferring users' private information or launching stealthy attacks. Meanwhile, the privacy protection schemes should be efficient as cloud users often use thin client devices to access the data. In this paper, we propose a lightweight scheme to protect the privacy of data access pattern. Comparing with existing state-of-the-art solutions, our scheme incurs less communication and computational overhead, requires significantly less storage space at the user side, while consuming similar storage space at the server. Rigorous proofs and extensive evaluations have been conducted to show that the proposed scheme can hide the data access pattern effectively in the long run after a reasonable number of accesses have been made.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.773-777
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• 2008

Today's mobile devices have characteristic of random mobility in the heterogeneous networks. Thus they should have various kinds of security requirements. To satisfy these requirements, there are many researches on security and authentication for mobile devices. TCG(Trusted Computing Group) designed TPM(Trusted Platform Module) for providing privacy and authentication to users. Also TCG suggest a protocol, called DAA(Direct Anonymous Attestation) which uses zero knowledge proof theory. In this paper, we will implement DAA protocol using Java and show the efficiency and the problems in the DAA protocol. Finally, we will suggest an efficient mobile DAA model through Java test module for the DAA protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2405-2423
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• 2012

In a traditional Single Sign-On (SSO) scheme, the user and the Service Providers (SPs) have given their trust to the Identity Provider (IdP) or Authentication Service Provider (ASP) for the authentication and correct assertion. However, we still need a better solution for the local/native true SSO to gain user confidence, whereby the trusted entity must play the role of the ASP between distinct SPs. This technical gap has been filled by Trusted Computing (TC), where the remote attestation approach introduced by the Trusted Computing Group (TCG) is to attest whether the remote platform integrity is indeed trusted or not. In this paper, we demonstrate a Trustworthy Mutual Attestation (TMutualA) protocol as a proof of concept implementation for a local true SSO using the Integrity Measurement Architecture (IMA) with the Trusted Platform Module (TPM). In our proposed protocol, firstly, the user and SP platform integrity are checked (i.e., hardware and software integrity state verification) before allowing access to a protected resource sited at the SP and releasing a user authentication token to the SP. We evaluated the performance of the proposed TMutualA protocol, in particular, the client and server attestation time and the round trip of the mutual attestation time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1238-1259
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• 2019

Saving energy is a big challenge for Wireless Sensor Networks (WSNs), which becomes even more critical in large-scale WSNs. Most energy waste is communication related, such as collision, overhearing and idle listening, so the schedule-based access which can avoid these wastes is preferred for WSNs. On the other hand, clustering technique is considered as the most promising solution for topology management in WSNs. Hence, providing interference-free clustering is vital for WSNs, especially for large-scale WSNs. However, schedule management in cluster-based networks is never a trivial work, since it requires inter-cluster cooperation. In this paper, we propose a clustering method, called Interference-Free Clustering Protocol (IFCP), to partition a WSN into interference-free clusters, making timeslot management much easier to achieve. Moreover, we model the clustering problem as a multi-objective optimization issue and use non-dominated sorting genetic algorithm II to solve it. Our proposal is finally compared with two adaptive clustering methods, HEED-CSMA and HEED-BMA, demonstrating that it achieves the good performance in terms of delay, packet delivery ratio, and energy consumption.

• Journal of Information Processing Systems
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• v.5 no.4
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• pp.187-196
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• 2009

This paper presents compact cryptographic hardware architecture suitable for the Mobile Trusted Module (MTM) that requires low-area and low-power characteristics. The built-in cryptographic engine in the MTM is one of the most important circuit blocks and contributes to the performance of the whole platform because it is used as the key primitive supporting digital signature, platform integrity and command authentication. Unlike personal computers, mobile platforms have very stringent limitations with respect to available power, physical circuit area, and cost. Therefore special architecture and design methods for a compact cryptographic hardware module are required. The proposed cryptographic hardware has a chip area of 38K gates for RSA and 12.4K gates for unified SHA-1 and SHA-256 respectively on a 0.25um CMOS process. The current consumption of the proposed cryptographic hardware consumes at most 3.96mA for RSA and 2.16mA for SHA computations under the 25MHz.