• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2004.10a
• /
• pp.369-372
• /
• 2004

유비쿼터스 환경에서는 프라이버시에 민감한 다양한 정보가 수집되고 이들이 통제되지 않은 채 배포될 수 있기 때문에 프라이버시 보호가 필수적이다. 유비쿼터스 환경에서 프라이버스 보안을 위해 사용되는 대표적인 방법론의 하나인 익명(anonymity) 기반 기법에서는, 사용자가 새로운 서비스 영역에 참여할 때 가명(pseudonym)을 사용할 수 있도록 하여, 사용자의 신분을 노출시키지 않도록 하는 방법이다. 이 방법은 사용자의 신분을 보호하는데는 효과적이지만, 친구 찾기 서비스, 위험지역경보, P2P통신 등 ID 기반의 서비스를 제공하기 어렵게 하는 단점이 있다. 이 논문에서는 익명기반의 프라이버스 보호 기법을 사용하는 유비쿼터스 환경에서 ID 기반의 서비스를 제공할 수 있도록 하는 시스템 구조를 제안한다.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2004.05a
• /
• pp.135-138
• /
• 2004

멀티미디어 기술의 급격한 발전으로 인해 대부분의 전송되는 파일들은 다양한 멀티미디어 데이터를 포함하고 있다. 이러한 멀티미디어 데이터를 전송할 때 송수신자의 익명성 보장은 최근 PET기술의 급격한 관심과 더불어 상당히 큰 이슈로 부각되고 있다. 그러므로 송수신자의 익명성을 보장하는 기술들에 관한 최근 연구 동향을 살펴보는 일은 중요하다. 본 논문에서는 다양한 멀티미디어 데이터를 전송 시 송수신자의 익명성을 보장하는 최근 기술 및 현황들을 Mix-net 기술을 중심으로 살펴본다.

• The KIPS Transactions:PartC
• /
• v.10C no.5
• /
• pp.533-540
• /
• 2003

According to the development of mobile communications, many people have been offered high qualify of the application services using portable terminals. But those works nay have many vulnerabilities and have the limit of excutaions. Because the application services are provided in mobile network and the performance of portable terminals is lower than that of base stations. To improve these problems, in this paper, we propose one-time proxy signature scheme that can reduce the computational ctsost on a user and prevent a proxy agent's dishonesty. The proposed scheme is based on the KBLK scheme [2] which applied the fail-stop signature scheme [1]. It is constructed that a proxy signer can sign only one message with a proxy key and we add anonimity to it for the user's identity protection in mobile communication like a M-commerce.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.1
• /
• pp.245-251
• /
• 2014

Mix network plays a key role in electronic voting to preserve anonymity and lots of mixnet schemes have been proposed so far. However, they requires complex and costly zero-knowledge proofs to provide their correct mixing operations. In 2010, Seb$\acute{e}$ et al. proposed an efficient and lightweight mixnet scheme based on a cryptographic secure hash function instead of zero-knowledge proofs. In this paper, we present a more efficient and faster mixnet scheme than Seb$\acute{e}$ et al.'s scheme under the same assumption. Also, our scheme is secure.

• Journal of the Korea Society of Computer and Information
• /
• v.10 no.3 s.35
• /
• pp.189-199
• /
• 2005

Now it is increasing the necessity for micropayment system according to activation for trade on internet. Because of the reason, it is requesting safety for personal information as well as for payment cost. But current micropayment systems cannot support anonymity or have heavy overheads in payment process. This paper suggests a micropayment system to keep anonymity of users and also to keep payment cost safe. The proposed system is to use blind signature anonymous ID which is combined nonce with an encryption of personal information. It also keeps payment cost of users by reconfirmation payment cost and product from certification and increases the computational efficiency by using secret key and session key instead of public key.

• The Journal of Engineering Research
• /
• v.7 no.1
• /
• pp.89-97
• /
• 2005

The GNUnet proposed a file encoding method by 1KB block size to support anonimity of file and decentralizes encoded block to peers through unstructed model. but, the encoding and block decentralizing method with 600~700MB large multimedia file appered two problems. First problem, it need addition R block and I block, which make about 4% of storage resource. Second problem, unstructed model added network load by broadcasting decentralizing method. The paper suggest variable encoding block size and structured model by block decentralizing solution. Suggested encoding method reduced block request supplementary block generation from 4% to 1%. and network load by proposal structured model sending answer through dedicated peer to decentralize block.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.81-90
• /
• 2006

The GNUnet proposed a file encoding method by 1KB block size to support anonimity of files, decentralizes encoded block to peers through unstructed mode and original data decoding method a block searching or encoded blocks. but, the encoding and block decentralizing method with $600\sim700MB$ large multimedia file appered two problems. First problem, it need addition R block and I block, which make about 4% of storage resource. Second problem, unstructured model added network load by broadcasting decentralizing method. Third problem, The critical point of keyword search function. This paper suggest variable encoding block size and structured model by block decentralizing solution. Suggested encoding method reduced block request supplementary block generation from 4% to 1%, network load by proposal structured model sending answer through dedicated peer to decentralize block and we defined content-based keyword and identifier of sharing file.

• Journal of the Korean Society for information Management
• /
• v.26 no.2
• /
• pp.27-41
• /
• 2009

With explosive growth in the area of the Internet and IT services, various types of digital contents are generated and circulated, for instance, as converted into digital-typed, secure electronic records or reports, which have high commercial value, e-tickets and so on. However, because those digital contents have commercial value, high-level security should be required for delivery between a consumer and a provider with non face-to-face method in online environment. As a digital contents, an e-ticket is a sort of electronic certificate to assure ticket-holder's proprietary rights of a real ticket. This paper focuses on e-ticket as a typical digital contents which has real commercial value. For secure delivery and use of digital contents in on/off environment, this paper proposes that 1) how to generate e-tickets in a remote e-ticket server, 2) how to authenticate a user and a smart card holding e-tickets for delivery in online environment, 3) how to save an e-ticket transferred through network into a smart card, 4) how to issue and authenticate e-tickets in offline, and 5) how to collect and discard outdated or used e-tickets.