• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.4
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• pp.1521-1537
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• 2021

Through information hiding technique, secret message can be hidden in pictures. Stego-image quality and hiding capacity are two important metrics for information hiding. To enhance these metrics, many schemes were proposed by scholars in recent years. Some of them are effective and successful, but there is still a room for further improvement. A high capacity information hiding scheme (PAMO, Pixel-value Adjustment with Modulus Operation Algorithm) is introduced in this paper. PAMO scheme uses pixel value adjustment with modulus operation to hide confidential data in cover-image. PAMO scheme and some referenced schemes are implemented in Python and experiments are carried out to evaluate their performance. In the experiments, PAMO scheme shows better performance than other methods do. When secret message length is less than 72000 bits, the highest hiding capacity of PAMO can reach 7 bits per pixel, at the same time the PSNR of stego-images is greater than 30 dB.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.3
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• pp.41-52
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• 1997

In this paper, we analyze two claws of Zhou-Gollmann's protocol. The protocol divide the message into a key K and a ciphertext C. The ciphertext C is delivered to the recipient, but the key K is submitted to the TTP, after the message originator receive the recipient's receipt for the ciphertext. TTP puts the key in the directory which is accesaible to the public. So, the recipient's obtaining the message dependson whether the originator submits the key or not. We will show that the originator. which is in such an advantageous position, could make the protocol be unfair and present how to improve the protocol. On the other hand, Zhou-Gollmann's protocol doesn't provide the secrecy of the message, since the key K is published. This means that, to send a secret message, additional mechanism is required. In this paper, we will present an improvement of Zhou-Gollmann's protocol to keep the message secret. The key distribution of the proposed protocol is based on the Diffie-Hellman's one.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1485-1494
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• 2015

Traditionally, data hiding has been done mainly in such a way that insert the data into the large-capacity multimedia files. However, the document files of the previous versions of Microsoft Office 2003 have been used as cover files as their structure are so similar to a File System that it is easy to hide data in them. If you open a compound-document file which has a secret message hidden in it with MS Office application, it is hard for users who don't know whether a secret message is hidden in the compound-document file to detect the secret message. This paper presents an analysis of Compound-File Binary Format features exploited in order to hide data and algorithms to detect the data hidden with these exploits. Studying methods used to hide data in unused area, unallocated area, reserved area and inserted streams led us to develop an algorithm to aid in the detection and examination of hidden data.

• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.20-29
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• 2007

Although E-mail system is considered as a most important communication media, 'Spam' is flooding the Internet with many copies of the same message, in an attempt to force the message on people who would not otherwise choose to receive it. Most spam is commercial advertising, often for dubious products, get-rich-quick schemes, or quasi-legal services. Therefore advanced anti-spam techniques are required to basically reduce its transmission volume on sender mail server or MTA, etc. In this study, we propose a new sender authentication model with encryption function based on modified DomainKey with SMS for Spam mail protection. From the SMS message, we can get secret information used for verification of its real sender on e-mail message. And by distributing this secret information with SMS like out-of-band channel, we can also combine proposed modules with existing PGP scheme for secure e-mail generation and authentication steps. Proposed scheme provide enhanced authentication function and security on Spam mail protection function because it is a 'dual mode' authentication mechanism.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.157-160
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• 2003

Recently, several steganographic algorithms for two-color binary images have been proposed. In this paper, we propose a steganographic algorithm which embeds a secret message into bitmap images and palette-based images. To embed a message, the suggested algorithm divides a bitmap image into bit-plane images from LSB-plane to MSB-plane for each pixel, and considers each bit-plane image as a binary one. The algorithm splits each bit-plane image into m$\times$n blocks. and embeds a r-bit(r=[log$_2$(mn+1]-1) message into the block. And our schemes embed a message to every bit-plane from LSB to MSB to maximize the amount of embedded message and to minimize the degradation. The schemes change at most two pixels in each block. Therefore, the maximal color changes of the new algorithm are much smaller than other bit-plane embedding schemes' such as the substantial substitution schemes.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.23-26
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• 2003

Westfeld[1] analyzed a sequential LSB embedding steganography effectively through the $\chi$$^2$-statistical test which measures the frequencies of PoVs(pairs of values). Fridrich also proposed another statistical analysis, so-called RS steganalysis by which the embedding message rate can be estimated. In this paper, we propose a new steganographic scheme which preserves the above two statistics. The proposed scheme embeds the secret message in the innocent image by randomly adding one to real pixel value or subtracting one from it, then adjusts the statistical measures to equal those of the original image.

• East Asian mathematical journal
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• v.39 no.3
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• pp.291-298
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• 2023

Recently, a new type of encryption called Homomorphic Authenticated Encryption (HAE) has been proposed. This combines the functionality of homomorphic encryption with authentication. Several concrete HAE schemes have been developed and security results for homomorphic authenticated encryption, designed by combining a homomorphic message authentication scheme with a homomorphic secret-key encryption, have been partially reported. In this paper, we analyze the security of a design method that combines homomorphic message authentication and homomorphic encryption, with a focus on the encryption after authentication (EAA) type. The results of our analysis show that while non-forgeability and indistinguishability are maintained, strong non-forgeability is not.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.526-539
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• 2012

This paper proposes a high capacity data hiding method using high frequence secret data indexing algorithm. Many novel data hiding methods based on LSB and PVD methods were presented to enlarge hiding capacity and provide an imperceptible quality. In this paper, first, calculating data iteration frequency of the secret message and make up the high frequency data index matrix (HFDT) using high frequence data's location information. Next, HFDT uses to that data hiding process on the cover image and recovering process on the stego image. The experimental results demonstrate the efficiency of the proposed high frequency secret data indexing method. For the data hiding method, experiments are conducted for four cases: 2 pattern secret data (2PD), 4 pattern secret data (4PD), 8 pattern secret data (8PD) and higher pattern secret data (HPD). When comparing the proposed method with other data hiding methods, for the HPD case, the results show that the proposed method has a good PSNR and more capacity, and for the other case, the results show that the proposed method has a higher PSNR and larger capacity.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.5
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• pp.51-56
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• 2014

In the digital world of the internet, steganography is introduced to hide the existence of the secret communication by concealing a secret message inside another unsuspicious cover medium. The third parties are unaware that a stego medium is being communicated. There exists a large variety of steganography methods based on texts. In this paper, analyzed the advantages and significant disadvantages of each existing text steganography method and how new approach could be proposed as a solution. The objective of this paper is to propose a method for hiding the secret messages in safer manner from external attacks by encryption rearrangement key.

• Journal of Multimedia Information System
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• v.8 no.1
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• pp.57-60
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• 2021

Industry 4.0 is continuous automation by applying the latest smart technologies to traditional manufacturing industries. It means that large-scale M2M (Machine-to-Machine) communication and IoT (Internet of Things) technologies are well integrated to build efficient production systems by analyzing and diagnosing various issues without human intervention. Edge computing is widely used for M2M services that handle real-time interactions between devices at industrial machinery tool sites. Here, secure data transmission is required while interacting. Thus, this paper focused on a method of creating and maintaining secret key and security tag used for message authentication between end-devices and edge-device.