• Journal of Internet Computing and Services
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• v.7 no.5
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• pp.1-12
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• 2006

In mobile database environments, the efficient synchronization technique is required to maintain the consistency of replicated data because the same data can be replicated between so many different databases, In this paper, we propose a message digest based synchronization technique to maintain the consistency of replicated data between client databases and a server database in mobile environments. The proposed data synchronization technique has the advantage of generality aspect and extensibility aspect by using the tuple-based message digest output to detect the data conflicts.

• Journal of KIISE:Databases
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• v.34 no.4
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• pp.357-368
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• 2007

This paper proposes the SAMD(Synchronization Algorithms based on Message Digest) algorithm based on message digest in order to data synchronization between a database server and a mobile database. The SAMD algorithm makes the images at the database server and the mobile database using message digest tables and compares two images in order to select the rows needed to synchronization. If two images are different, the synchronization is progressed according to synchronization policy. The SAMD algorithm does not use techniques which are dependent the some database vendor and also triggers, stored procedures and timestamps. The SAMD only uses the standard SQL functions for the synchronization. Therefore the SAMD algorithm is used in any combinations of the database server and the mobile database because the SAMD algorithm is not depended on some database venders. Also the SAMD algorithm shows better performance compared with existing synchronization products.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.592-596
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• 2002

Can speak that DTD is meta data that define meaning of expressed data on XML document. Therefore, In case DTD information is damaged this information to base security of XML document dangerous. Not that attach digital signature on XML document at send-receive process of XML document in this research, proposed method to attach digital signature to DTD. As reading DTD file to end first, do parsing, and store abstracted element or attribute entitys in hash table. Read hash table and achieve message digest if parsing is ended. Compose and create digital signature with individual key after achievement. When sign digital, problem that create entirely other digest cost because do not examine about order that change at message digest process is happened. This solved by method to create DTD's digital signature using DOM that can embody tree structure for standard structure and document.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.77-84
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• 2003

A mobile agent is a program which represents a user in a network and is capable of migrating from one node to another node, performing computations on behalf of the user. In this paper, we suggest a scheme that can safely recover mobile agent using the checkpoint that is saved at the platform that it visited previously and restart its execution from the abnormal termination point of the mobile agent. For security, mobile agent uses its public key to encrypt the checkpoint and the home platform uses the private key of the mobile agent to decrypt the encrypted checkpoints at the recovery stage. When home platform receives the checkpoint of the mobile agent, home platform verifies the checkpoint using message digest. Home platform verifies the correctness of the checkpoint by comparing the message digest generated at checkpoint mention time with the message digest generated at mobile agent recovery time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1080-1083
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• 2005

Can speak that DTD is meta data that define meaning of expressed data on XML document. Therefore, in case DTD information is damaged this information to base security of XML document dangerous. Not that attach digital signature on XML document at send-receive process of XML document in this research, proposed method to attach digital signature to DTD. As reading DTD file to end first, do parsing, and store abstracted element or attribute entitys in hash table. Read hash table and achieve message digest if parsing is ended. Compose and create digital signature with individual key after achievement. When sign digital, problem that create entirely other digest cost because do not examine about order that change at message digest process is happened. This solved by method to create DTD's digital signature using DOM that can embody tree structure for standard structure and document.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.1015-1022
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• 2012

This paper deals with hardware design which unifies MD5 and HAS-160 hash algorithms. Two algorithms get a message with arbitrary length and process message blocks divided into 512 bits each time and output a hash code with a fixed length. MD5 ouputs a hash code of 128 bits and HAS-160 a hash code of 160 bits. The unified hash core designed has 32% of slices overhead compared to HAS-160 core. However, there is only a fixed message buffer space used. The unified hash core which run a step in one clock cycle operates at 92MHz and has performance which digests a message in the speed of 724Mbps at MD5 and 581Mbps at HAS-160 hash mode. The unified hash core which is designed can be applicable to the areas such as E-commerce, data integrity and digital signature.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.519-525
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• 2003

Technology that develop existent EDI according to electronic commerce environment by XML's entrance on the stage is XML/EDI. The DTD is meta data that define meaning of expressed data on XML document. Therefore, in case DTD information is damaged this information to base security of XML document dangerous. Not that attach digital signature on XML document for XML/EDI that is encoded in internet shopping mall in this research, proposed method to attach digital signature to DTD. When sign digital, problem that create entirely other digest cost because do not examine about order that change at message digest process is happened. This solved by method to create DTD's digital signature using DOM that can embody tree structure for standard structure and document.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.4
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• pp.797-803
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• 2012

Recently demands in construction of the stand-alone networks and interconnection between convergence devices have led an increase in research on and much attention has been paid to the application of MANET as a Ubiquitous network which is growing fast. With performance both as hosts and routers, easy network configuration, and fast response, mobile nodes participating in MANET are suitable for Embedded computing, but have vulnerable points, such as lack of network scalability and dynamic network topology due to mobility, passive attacks, active attacks, which make continuous security service impossible. In this study, hashed AODV routing is used to protect from counterfeiting messages by malicious nodes in the course of path finding and setting, and disguising misrouted messages as different mobile nodes and inputting them into the network.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.95-99
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• 2003

XML은 SGML(Standard Generalized Markup Language)의 간략화된 버전으로 SGML의 확장성, 구조, 검증의 특성을 계승하고 있다. 이런 장점으로 XML은 발표된 이래로 인터넷 상의 자료표현의 표준으로 각광받고 있다. 그러나, XML은 문서의 데이터 포맷 표현을 향상시키는데 중점을 두고 만들어졌기 때문에 문서변조 및 데이터 삭제 등의 공격에 취약한 문제점을 가지고 있다. 이러한 문제점에 대한 해결책으로 XML 전자 서명, XML 암호화 기법, XML 접근 제어와 같은 다양한 해결책이 제시되었다. 본 논문에서는 XML 문서에만 전자서명을 첨부하는 것이 아니라, DTD에 전자 서명을 첨부하는 방법을 제안하였다. 먼저 DTD파일을 끝까지 읽으면서 파싱을 하고 여기서 추출되는 엘리먼트나 속성, 엔티티들을 해쉬테이블에 저장한다. 파싱이 종료되면 해쉬 테이블을 읽어 들여서 메시지 다이제스트를 수행한다. 수행 후 이를 개인 키와 합성하여 전자 서명을 생성한다.

• Journal of Information Technology Services
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• v.8 no.2
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• pp.157-171
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• 2009

In mobile XML environments, the efficient synchronization technique is required to maintain the consistency of replicated XML data because the same data can be replicated between so many different XML documents. In this paper, we propose a message digest based synchronization technique to maintain the consistency of replicated data between client XML documents and a server XML database in mobile XML environments. The proposed an XML data synchronization technique(XSA) has the advantage of model generality aspect and storage space aspect by using the tuple-based message digest table to detect the data conflicts. The proposed technique can be applicable to the application requiring the consistency of replicated XML data without any restrictions in the heterogeneous(between hierarchical XML documents and relational XML databases) mobile environments.