Myungjin Choi

An efficient and secure anonymous authentication scheme for mobile satellite communication systems

This paper proposes a new efficient and secure anonymous authentication scheme for mobile satellite communication systems. Compared with the related schemes, the proposed scheme achieves the following three main advantages: (1) It is just based on a secure one-way hash function for avoiding complex computations for both mobile users and network control center (NCC), (2) it does not require sensitive verification table which may cause NCC to become an attractive target for numerous attacks (e.g., insertion attacks and stolen-verifier attacks), and (3) it provides higher security level (e.g., secure mutual authentication and key establishment, confidential communication, users privacy, simple key management, and session key independence). As a result, the proposed scheme is very suitable for lightweight-device environments because of very low computation overload on the part of both mobile user and NCC.

A New Efficient Key Agreement Scheme for VSAT Satellite Communications Based on Elliptic Curve Cryptosystem

A satellite communication is suitable for broadcasting service and long-hual transmission based on telecommunications. In the satellite communication environment, unauthorized user should not have to obtain his/her required services from the satellite communication systems without authentication. Therefore, authentication is an important security technique to prevent illegal service requests. Quite recently, Lee-Lin-Hwang proposed a secure scheme based on key agreement scheme with mutual authentication to solve the security problems on the VSAT satellite communications. However, Lee-Lin-Hwangs scheme is inefficiently designed because it is based on the RSA cryptosystem. Therefore, the scheme cannot be applicable for the low-power satellite communication environments because it involves high communication and computation costs. Based on these motivations, this paper proposes a new efficient and secure key agreement scheme for VSAT satellite communications based on elliptic curve cryptosystem (ECC) to minimize the complexity of computational costs between VSAT and HUB and fit VSAT satellite communication environments. Compared with previous schemes, the newly proposed scheme has the following more practical merits: (1) it provides secure session key agreement function by adopting elliptic curve cryptosystem, (2) it can reduce the total execution time and memory requirement due to the elliptic curve cryptography, and (3) it not only is secure against well-known cryptographical attacks but also provides perfect forward secrecy. As a result, the proposed scheme is extremely suitable for use in satellite communication environments since it provides security, reliability, and efficiency. http://dx.doi.org/10.5755/j01.itc.40.3.634

Cryptanalysis of an Enhanced Spatiotemporal Chaotic Image/Video Cryptosystem

Recently, an enhanced spatiotemporal chaotic image/video cryptosystem was proposed by Rhouma and Belghith. This paper demonstrates that the enhanced cryptosystem is not secure against the following three different classical types of attacks: chosen plaintext, chosen ciphertext, and known plaintext. In the three attacks, only a pair of (plaintext/ciphertext) was needed to totally break the cryptosystem.

Fast multi-spectral image registration based on a statistical learning technique

Statistical learning techniques have been used to dramatically speed-up keypoint matching and image registration. However, they are rarely applied to multi-spectral images. Statistical learning techniques regard various intensities as distinctive patterns. Thus, corresponding features extracted from multi-spectral images are recognized as different patterns, because the features have different intensity characteristics. In order to overcome this problem, we propose a novel statistical learning method that can be extended to multi-spectral images. The proposed approach obtains responses from multiple classifiers that are trained with well-registered multi-spectral images, in contrast to earlier approaches using one classifier. The responses of corresponding features can be similarly characterized as being of the same class even though the intensities of the corresponding features are quite different. The experimental results show that our method provides good performance on multi-spectral image registration compared to current methods.

Robust pan-sharpening via color samples relocation and edge aware interpolation

We present a pan-sharpening method that can produce high quality high-resolution multispectral image by fusing a high-resolution panchromatic image with a low resolution multispectral image. The major benefits of our approach are the color samples relocation algorithm and the optimization based edge aware interpolation method which protect the reconstructed images from aliasing and color diffusion artifacts around edge areas that are commonly arose in previous pan-sharpening algorithms. Our approach is robust to misalignment errors between the high-resolution panchromatic image and the low resolution multispectral image. We evaluate our results quantitatively and qualitatively on both synthetic and real world satellite images.

Parallel Processing with MPI for Inter-band Registration in Remote Sensing

Inter-band registration is an essential processing method that is used to generate satellite imagery products with raw data obtained from a high-resolution satellite. The processing method requires considerable time owing to its high computational cost as well as the large-scale data to be processed. In this paper, we present a parallel inter-band registration method on windows-based clusters as part of an effort to reduce the total execution time during product generation. We use a blade system as clusters and the MPICH2 library for the parallel programming tool. We logically divide roles of the nodes into one root node, three sub-root nodes, and several compute nodes. We divide the inter-band registration into sequential and parallel processing areas to design the nodes suitable for inter-band registration. The root node and sub-root nodes control the sequential processing area and exchange data with compute nodes in the parallel processing area. In addition, we introduce an object-oriented pseudo code for easy parallelization using a Message Passing Interface (MPI). We apply our system on the KOMPSAT-2 product generation process. The experimental result shows that our system reduces the total execution time from 330 seconds to 79 seconds.

The KOMPSAT-5 Image Reception and Processing Element

KOREAs first synthetic aperture radar (SAR) satellite, KOMPSAT-5, is now ready to launch in the middle of 2011. The KOMPSAT-5 will be delivered to low Earth orbit for all-weather day-night monitoring of the Korean peninsula. The primary mission goal is to provide GOLDEN mission: Geographic information system, Ocean management, Land management, Disaster monitoring, and ENvironment monitoring. In order to fulfill the GOLDEN mission, the KOMPSAT-5 will use COSI (COrea SAR Instrument) payload to provide high-resolution mode SAR images of 1 m resolution, standard mode SAR images of 3 m resolution, and wide-swath mode SAR images of 20 m resolution, all with the viewing condition of a 45-degree incidence angle. The KOMPSAT-5 Ground Segment (KGS) constitutes three central elements—Mission Control Element, Calibration and Verification Element, and Image Reception and Processing Element (IRPE)—for controlling and operating the KOMPSAT-5 satellite; for calibrating its COSI payload; for archiving the SAR data; and for generating and distributing basic products. This paper outlines the KGS layout, describes the IRPE in more detail, and presents the overall operational workflow.