• Convergence Security Journal
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• v.15 no.4
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• pp.91-97
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• 2015

General companies consider saving the information after enciphering as law. However, if the actual information is saved as enciphered, the decoding process must be conducted when the information is searched or edited in the ser ver. Therefore, process delay time occurs and is less efficient. This kind of work gives burden to the server, so the companies or managers handling the server do not save the information after enciphering. In this paper, the Networ k constructs and realizes an efficient security data management system that ensures safety and haste in operating u sing the homomorphic encryption technology, which collects information and decides quickly, and enables editing the encryption without a decoding process. To ensure the security of the embodied system, the existing encryption algo rithm can be used. Search method to use the keyword search. Additionally, by using a trapdoor, the keyword is not expose and it is changed whenever it is searched, and the formation of the keyword does not get exposed.

• Journal of KIISE:Databases
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• v.32 no.4
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• pp.441-451
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• 2005

HTML is mostly stored in native file systems instead of specialized repositories such as a database. Like HTML, XML, the standard for the exchange and the representation of data in the Internet, is mostly resident on native file systems. However. since XML data is irregular and verbose, the disk space and the network bandwidth are wasted compared to those of regularly structured data. To overcome this inefficiency of XML data, the research on the compression of XML data has been conducted. Among recently proposed XML compression techniques, some techniques do not support querying compressed data, while other techniques which support querying compressed data blindly encode data values using predefined encoding methods without considering the types of data values which necessitates partial decompression for processing range queries. As a result, the query performance on compressed XML data is degraded. Thus, this research proposes an XML compression technique which supports direct and efficient evaluations of queries on compressed XML data. This XML compression technique adopts an encoding method, called dictionary encoding, to encode each tag of XML data and applies proper encoding methods for encoding data values according to the inferred types of data values. Also, through the implementation and the performance evaluation of the XML compression technique proposed in this research, it is shown that the implemented XML compressor efficiently compresses real-life XML data lets and achieves significant improvements on query performance for compressed XML data.