• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.499-507
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• 2007

In the areas of CAE, CAD and CAO integration & automation technology, the word 'File Wrapping' means a virtualization of TEXT files that supports variables-based I/Os like variable assignments in programming languages. This File Wrapping process is one of the cornerstones of CAE, CAD and GAO integration & automation, and the performance of File Wrapping process, which is depending on the sire of a TEXT file to be accessed and the number of regions and their distribution, has a critical effect on the total performance of the CAE, CAD and CAO integration & automation systems. In this paper, we define TEXT File Region Management which generalizes the main functions of the File Wrapping process, and describe a prototype of TEXT file Region Management which is implemented as a Grid service. After that, the validity of the proposed model and the TEXT File Region Management service are discussed with evaluation results of the prototype.

• International Journal of Computer Science & Network Security
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• v.21 no.12
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• pp.53-60
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• 2021

Many standard methods are used for secret text files and secrete short messages cryptography, these methods are efficient when the text to be encrypted is small, and the efficiency will rapidly decrease when increasing the text size, also these methods sometimes have a low level of security, this level will depend on the PK length and sometimes it may be hacked. In this paper, a new method will be introduced to improve the data protection level by using a changeable secrete speech file to generate PK. Highly Secure Data Encryption (HSDE) method will be implemented and tested for data quality levels to ensure that the HSDE destroys the data in the encryption phase, and recover the original data in the decryption phase. Some standard methods of data cryptography will be implemented; comparisons will be done to justify the enhancements provided by the proposed method.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.967-970
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• 2005

The Music Player MAF Player Format of ISO/IEC 23000-2 FDIS consists of MP3 data, MPEG-7 metadata and one optional JPEG image data based on MPEG-4 File Format. However, the current Music Player MAF format does not allow multiple JPEG image data or timed text data. It is helpful to use timed text data and multiple JPEG images in the various multimedia applications. For example, listening material for the foreign language needs an additional book which has text and images, the audio contents which can get image and text data can be helpful to understand the whole story and situations well. In this paper, we propose the detailed file structure in conjunction with MPEG-4 File Format in order to improve the functionalities, which carry multiple image data and text data with synchronization information between MP3 data and other resources.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.392-401
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• 2021

When a data file is shared through various methods on the Internet, the data file may be damaged in various cases. To prevent this, some websites provide the checksum value of the download target file in text data type. The checksum value provided in this way is then compared with the checksum value of the downloaded file and the published checksum value. If they are the same, the file is regarded as the same. However, the checksum value provided in text form is easily tampered with by an attacker. Because of this, if the correct checksum cannot be verified, the reliability and integrity of the data file cannot be ensured. In this paper, a checksum value is generated to ensure the integrity and reliability of a data file, and this value and related file information are stored in the blockchain. After that, we will introduce the research contents for designing and implementing a system that provides a function to share the checksum value stored in the block chain and compare it with other people's files.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.446-449
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• 2002

This paper represents a improved data compression algorithm of mixed text file by 2 byte completion Hangout and 1 byte alphabet from. Original LZW algorithm efficiently compress a alphabet text file but inefficiently compress a 2 byte completion Hangout text file. To solve this problem, data compression algorithm using 2 byte prefix field and 2 byte suffix field for compression table have developed. But it have a another problem that is compression ratio of alphabet text file decreased. In this paper, we proposes improved LZW algorithm, that is, compression table in the Extended LZW(ELZW) algorithm uses 2 byte prefix field for pointer of a table and 1 byte suffix field for repeat counter. where, a prefix field uses a pointer(index) of compression table and a suffix field uses a counter of overlapping or recursion text data in compression table. To increase compression ratio, after construction of compression table, table data are properly packed as different bit string in accordance with a alphabet, Hangout, and pointer respectively. Therefore, proposed ELZW algorithm is superior to 1 byte LZW algorithm as 7.0125 percent and superior to 2 byte LZW algorithm as 11.725 percent. This paper represents a improved data Compression algorithm of mixed text file by 2 byte completion Hangout and 1 byte alphabet form. This document is an example of what your camera-ready manuscript to ITC-CSCC 2002 should look like. Authors are asked to conform to the directions reported in this document.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.43-51
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• 2010

It is meaningful to investigate data in unallocated space because we can investigate the deleted data. Consecutively complete file recovery using the File Carving is possible in unallocated area, but noncontiguous or incomplete data recovery is impossible. Typically, the analysis of the data fragments are needed because they should contain large amounts of information. Microsoft Word, Excel, PowerPoint and PDF document file's text are stored using compression or specific document format. If the part of aforementioned document file was stored in unallocated data fragment, text extraction is possible using specific document format. In this paper, we suggest the method of extracting a particular document file text in unallocated data fragment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.1
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• pp.170-191
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• 2024

The transmission of confidential data using cover media is called steganography. The three requirements of any effective steganography system are high embedding capacity, security, and imperceptibility. The text file's structure, which makes syntax and grammar more visually obvious than in other media, contributes to its poor imperceptibility. Text steganography is regarded as the most challenging carrier to hide secret data because of its insufficient redundant data compared to other digital objects. Unicode characters, especially non-printing or invisible, are employed for hiding data by mapping a specific amount of secret data bits in each character and inserting the character into cover text spaces. These characters are known with limited spaces to embed secret data. Current studies that used Unicode characters in text steganography focused on increasing the data hiding capacity with insufficient redundant data in a text file. A sequential embedding pattern is often selected and included in all available positions in the cover text. This embedding pattern negatively affects the text steganography system's imperceptibility and security. Thus, this study attempts to solve these limitations using the Part-of-speech (POS) tagging technique combined with the randomization concept in data hiding. Combining these two techniques allows inserting the Unicode characters in randomized patterns with specific positions in the cover text to increase data hiding capacity with minimum effects on imperceptibility and security. Format-preserving encryption (FPE) is also used to encrypt a secret message without changing its size before the embedding processes. By comparing the proposed technique to already existing ones, the results demonstrate that it fulfils the cover file's capacity, imperceptibility, and security requirements.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1790-1806
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• 2016

Digital image encryption is widely used for image data security. JPEG standard compresses image with great performance on reducing file size. Thus, to encrypt an image in JPEG format we should keep the quality of original image and reduced size. This paper proposes a JPEG image encryption scheme based on quantized DC and non-zero AC coefficients inner category scrambling. Instead of coefficient value encryption, the address of coefficient is encrypted to get the address of cipher text. Then 8*8 blocks are shuffled. Chaotic iteration is employed to generate chaotic sequences for address scrambling and block shuffling. Analysis of simulation shows the proposed scheme is resistant to common attacks. Moreover, the proposed method keeps the file size of the encrypted image in an acceptable range compared with the plain text. To enlarge the cipher text possible space and improve the resistance to sophisticated attacks, several additional procedures are further developed. Contrast experiments verify these procedures can refine the proposed scheme and achieve significant improvements.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.9 no.1
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• pp.39-52
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• 1998

The purpose of this study is to design the solution for creating full-text database of Korean dissertaion, After considering file formats for text based and image based database, Viewer, Search, Copy Right, Abstracts and Indexes, situation of Korea University Library, decided the principles of creating database. And suggested the design to produce the database for Korea University Library, that is easy to get file format conversion in case of the introducing new technology for the future.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.319-325
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• 2014

Since smart phones or tablet PCs have been widely used recently, the users can create and edit documents anywhere in real time. If the input and edit flows of documents can be traced, it can be used as evidence in digital forensic investigation. The typical document application is the MS(Microsoft) Office. As the MS Office applications consist of two file formats that Compound Document File Format which had been used from version 97 to 2003 and OOXML(Office Open XML) File Format which has been used from version 2007 to now. The studies on MS Office files were for making a decision whether the file has been tampered or not through detection of concealed items or analysis of documents properties so far. This paper analyzed the input order of text cells on MS Excel files and shows how to figure out what cell is the last edited in digital forensic perspective.