• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1831-1834
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• 2003

부정자 추적 기법(traitor tracing)은 컨텐츠에 대한 무단 배포, 불법 복사 등의 부정 행위를 한 부정자(traitor)를 추적할 수 있는 방식이다. 본 논문은 부정자 추적 기법을 이용하여 디지털 방송용 컨텐츠 보호 시스템 모델을 구성하고자 한다. 기존의 traitor tracing 기법들이 암호학적 측면에서 키 유출에 대한 부정을 추적하기 위한 방식들이었다면, dynamic traitor tracing 기법과 sequential traitor tracing 기법은 복호화된 후의 컨텐츠에 대한 부정 배포를 막기 위한 방식이다. 본 논문에서는 sequential traitor tracing 기법을 기반으로 하여 컨텐츠 암호화 키 생성 및 전송 그리고 키 유출에 대한 추적 기능까지 제공하는 부정자 추적 기법을 제안하여 디지털 방송용 컨텐츠 보호 시스템에 대한 모델을 구성하고자 한다.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.46-56
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• 2012

Traitor Tracing schemes are broadcast encryption systems where at least one of the traitors who were implicated in the construction of a pirate decoder can be traced. This traceability is required in various contents delivery system like satellite broadcast, DMB, pay-TV, DVD and so on. In this paper, we propose a public key traitor tracing scheme with key-update method. If the system manager can update a secret key which is stored in an authorized decode, it makes a pirate decoder useless by updating a secret key A pirate decoder which cannot update a secret key does not decrypt contents in next session or during tracing a traitor, this scheme has merits which will make a pirate decoder useless, therefore this scheme raises the security to a higher level.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.799-802
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• 2007

Broadcast encryption has been applied to transmit digital information such as multimedia, software and paid TV programs on the open networks. This paper presents a method called Traitor Tracing to solve all these problems. Traitor tracing can check attackers and trace them. It also utilizes a proactive way for each user to have effective renewal cycle to generate keys.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.6
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• pp.1231-1242
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• 2012

Traitor tracing schemes deter traitors from sharing their private keys by tracing at least one of the subscribers who were implicated in the construction of a pirate decoder. In general, it is assumed that the system manager in the scheme generates and distributes the subscribers' private key. But if the system manager knows the subscribers' private keys, he cannot convince a third party of a certain subscriber's piracy. To solve this problem, the system manager should not know the whole parts of subscribers' private keys and this leads to researches of asymmetric schemes. Moreover for the purpose of enhancing subscribers' privacy, there were two proposals of introducing anonymity onto asymmetric traitor tracing schemes, but one of them turned out to be a failure. In this paper, we point out that the other proposal also has flaws. We consider how to introduce anonymity to traitor tracing schemes, as a result, we suggest a new framework which is practical. We also construct a scheme by using an anonymous credential system and an asymmetric traitor tracing scheme. We prove the security of our scheme and consider the typical applications.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.5
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• pp.31-42
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• 2001

Two important requirements in broadcast encryption schemes are traitor traceability and revocability. In this paper, we propose a new type of a traitor tracing scheme that can revoke an unlimited number of traitors\` personal keys. Additionally, we propose an efficient and simple method to provide self-enforcement property. We also describe a variant of our scheme of which encryption algorithm is secure against adaptive chosen ciphertext attacks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.121-127
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• 2003

The threshold value of the traitor-tracing schemes means a maximum number of traitors whose identities can be uniquely exposed using the tracing scheme. In the traitor-tracing scheme based on an error-correcting code, which is focused at this paper, the threshold value is determined by the error-correcting capability of the underlying error-correcting code. Analyzed in terms of a combinatorial property of the tracing scheme is the resulting effect on the tracing scheme when the collusion size is over the threshold value, and a possibility of two disjoint groups of users making an identical unauthorized decryption key is shown.

• Journal of Advanced Navigation Technology
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• v.12 no.3
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• pp.245-254
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• 2008

If the broadcast message is sent, first of all, the privileged users will decode the session key by using his or her personal key, which the user got previously. The user willget the digital information through this session key. As shown above, the user will obtain messages or session keys using the keys transmitted from a broadcaster, which process requires effective ways for the broadcaster to generate and distribute keys. In addition, when a user wants to withdraw or sign up, an effective process to renew a key is required. It is also necessary to chase and check users' malicious activities or attacking others. This paper presents a method called Traitor Tracing to solve all these problems. Traitor tracing can check attackers and trace them. It also utilizes a proactive way for each user to have effective renewal cycle to generate keys.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.99-101
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• 2002

At ACISP'02, H.J. Kim et al.[1] proposed a new traitor tracing scheme. However, this paper show that the proposed scheme is to be insecure by presenting a conspiracy attack. Using our attack, any two subscribers can collaborate to derive the secret key of the data supplier and tell or sell it to any body. Thus, the unauthorized user can always decrypt the encrypted session key with the decrypted session key. Also the two subscribers cannot be traced by the data supplier

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.635-641
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• 2010

In this paper, we propose an efficient public key broadcast encryption system which can also extend traitor trace and revoke system. Although the proposed system has limited collusion size, the ciphertext size in the system can be sublinear in the number of total users, the private key size is constant, the computational cost can be sublinear and it can support black-box tracing algorithm, therefore, our system can be an option to applications where reducing the ciphertext size, private key size is a top priority. Furthermore, we can also apply our system to military document broadcast system, because it has such an efficient measurement.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.3
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• pp.49-61
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• 2004

In broadcast encryption schemes, traceability is a useful property to trace authorized subscribers, called traitors, who collude for manufacturing a pirate decoder. Unfortunately, this is usually achieved with a sacrifice of a privacy. Most traitor tracing schemes in the literature have been developed without considering a subscriber's anonymity, which is one of important requirements for electronic marketplaces to offer similar privacy as current marketplace. It would be unsatisfactory for the subscriber to reveal his/her identity to purchase multimedia contents. In this paper we propose an anonymous broadcast encryption scheme, where a user can subscribe anonymously and one purchases multimedia contents without giving a lot of information about his lifestyle, habits, and etc, but anonymity control is provided, i.e., a data supplier can date traitors.