• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1090-1096
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• 2002

The HTTP does not support continuity for browser-server interaction between successive visits or a user due to a stateless feature. Cookies were invented to maintain continuity and state on the Web. Because cookies are transmitted in plain and contain text-character strings encoding relevant information about the user, the attacker can easily copy and modify them for his undue profit. In this paper, we design a secure cookies scheme based on X.509 public key certificate for solving these security weakness of typical web cookies. Our secure cookies scheme provides not only mutual authentication between client and server but also confidentiality and integrity of user information. Additionally, we implement our secure cookies scheme and compare it to the performance with SSL(Secure Socket Layer) protocol that is widely used for security of HTTP environment.

• ETRI Journal
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• v.43 no.3
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• pp.447-458
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• 2021

The quality of experience (QoE) of video streaming is degraded by playback interruptions, which can be mitigated by the playout buffers of end users. To analyze the impact of playout buffer dynamics on the QoE of wireless adaptive hypertext transfer protocol (HTTP) progressive video, we model the playout buffer as a G/D/1 queue with an arbitrary packet arrival rate and deterministic service time. Because all video packets within a block must be available in the playout buffer before that block is decoded, playback interruption can occur even when the playout buffer is non-empty. We analyze the queue length evolution of the playout buffer using diffusion approximation. Closed-form expressions for user-perceived video quality are derived in terms of the buffering delay, playback duration, and interruption probability for an infinite buffer size, the packet loss probability and re-buffering probability for a finite buffer size. Simulation results verify our theoretical analysis and reveal that the impact of playout buffer dynamics on QoE is content dependent, which can contribute to the design of QoE-driven wireless adaptive HTTP progressive video management.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.249-258
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• 2006

WebDAV is an IETF standard protocol, which is an extended version of HTTP 1.1, supporting asynchronous collaborative authoring of various contents on the web. Recently, to precisely control access to the resources on a WebDAY server, the WebDAV Access Control Protocol was published. This protocol helps developers to implement advanced server functionalities in a convenient way by providing various control methods to the resources on the WebDAV server. Based on the WebDAV access control protocol, we developed Open Workspaces, which systematically support exchanging and sharing data for general visitors. An Open Workspace can be supplied as a Download-Only Open Workspace, an Upload-Only Open Workspace, or an Upload-Download Open Workspace. Any registered user can create these workspaces without bothering the system administrator. To support the Open Workspaces, we extended the Slide WebDAV server and the DAVExplorer WebDAV client, which are being used popularly.

• 대한공업교육학회지
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• v.33 no.2
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• pp.287-299
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• 2008

HTTP is one of the most widely used protocols of the WWW. Currently it uses TCP as the transport layer protocol to provide reliability. The HTTP uses separate TCP connection for each file request and adds unnecessary head-of-line blocking overhead for the file retrieval. The web application is short sized and affected by the increased handover latency of TCP in wireless environment. SCTP has attractive features such as multi-streaming and multi-homing. SCTP's multi-streaming and multi-homing avoid head-of-line blocking problem of TCP and reduce handover latency of TCP in wired and wireless environment. Mean response time is the important measure in most web application. In this paper, we present the comparison of mean response time between HTTP over SCTP with that of HTTP over TCP in wired and wireless environments using NS-2 simulator. We measured mean response time for varying packet loss rate, bandwidth, RTT, and the number of web objects in wired environment and mean response time and packet loss rate for varying moving speed and region size in wireless environment. Our experimental result shows that SCTP reduces the mean response time of TCP based web traffic.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.514-517
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• 2000

본 논문에서는 사실상 무선 인터넷 프로토콜의 표준인 WAP(Wireless Application Protocol)의 구조 및 동작을 살펴보고, 안전한 통신을 위한 WTLS(Wireless Transport Security) 프로토콜 동작 및 그 취약성에 대해 논의한다. 또한 WAP 및 HTTP 상에서 안전한 유무선 통합 서비스를 위한 여러 방안을 살펴보고 결론을 유도한다.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.141-148
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• 2015

In this paper, for developing and implementing the HLS(Http Live Streaming) transmitter based embedded linux which is operated easily and cheap and lower power, portable in all networks and client environments compared to exist video live streaming transmitters. We design the developed HLS transmitter hardware using the Arm11 core and then porting the Embedded Linux OS(Operating System) and implementing the HLS protocol using the open source FFmpeg and Segmenter. For proving the performance of developed HLS transmitter, we make the testing environment for testing the performance of HLS transmitter including the notebook, iPhone, android Phone, Notebook and then analysis the received video in the client displayer. In this paper, we suggest the developed HLS transmitter performance data values higher than the Apple company's HLS recommended specification values and the picture of developed HLS transmitter operation in the testing environment. The application field of this paper result is that the man who works in the emergency situation take HLS and transmit the live emergency situation to the head quarter using this portable HLS.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.313-320
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• 2015

While various phishing attacks are getting to be increased in constant, their response methods still stay on the stage of responding after identifying an attack. To detect a phishing site ahead of an attack, a method has been suggested with utilizing the Referer header field of HTTP. However, it has a limitation to implement a traffic gathering system for each of prospective target hosts. This paper presents a unknown phishing site detection method in the Interior network environment. Whenever a user try to connect a phishing site, its traffic is pre-processed with considering of the characteristics of HTTP protocol and phishing site. The phishing site detection phase detects a suspicious site under phishing with analysing HTTP content. To validate the proposed method, some evaluations were conducted with 100 phishing URLs along with 100 normal URLs. The experimental results show that our method achieves higher phishing site detection rate than that of existing detection methods, as 66% detection rate for the phishing URLs, and 0% false negative rate for the normal URLs.

• Journal of the Korea Society of Computer and Information
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• v.18 no.8
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• pp.95-104
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• 2013

DDoS attacks have became as a social threat since 2009 7.7 DDoS turmoil. Even though defence techniques have been developing to provide against those threats, they become much more sophisticate. In recent years, the attack form of DDoS is changing from high amount of traffic attack of network layers to highly sophisticate small amount of application layers. To make matters worse, attack agent for the attack has became very intelligent so that it is difficult to be blocked since it can't be distinguished from normal PCs. In the user authentication system(such as CAPTCHA) User intervention is required to distinguish normal PCs and intelligent attack agents and in particular, in a NAT environment, IP-based blocking method can be cut off the normal users traffic at the same time. This research examined defense techniques which are able to distinguish between agent and normal PC and effectively block ways the HTTP DDoS offense applying one-time session key based authentication method using Cookie which is used in HTTP protocol to protect web sever from sophisticate application layer of DDoS.

• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.129-136
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• 2005

WebDAV extends the web communication protocol HTTP/1.1 to provide a distributed authoring and versioning across the Internet. A property management, the principal ability of WebDAV, has many advantages for managing and utilizing additional information of server resources as well as supports a role of storage. Most WebDAV Application systems currently available are using WebDAV for providing simple storage space, not for the functionality of property management. However, to develop an advanced application such as a collaborative system based on WebDAV, it is very important to design and utilize user-defined WebDAV properties. In this paper, we propose DavSUDP(WebDAV Simple User-defined Property Definition Protocol) that describes XML-based configurations representing WebDAV user-defined properties and their processing steps. DavSUDP enables WebDAV servers to effectively manage user-defined properties in developing WebDAV-based applications. To show this, we extended the Apache mod_dav module to support DavSVDP and developed the OpenSpace in the iPlace collaborative system using the extended Apache web server.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.128-134
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• 2016

IoT devices including smart devices are connected with internet, thus they have security threats everytime. Particularly, IoT devices are composed of low performance MCU and small-capacity memory because they are miniaturized, so they are likely to be exposed to various security threats like DoS attacks. In addition, in case of IoT devices installed for a remote place, it's not easy for users to control continuously them and to install immediately security patch for them. For most of IoT devices connected directly with internet under user's intention, devices exposed to outside by setting IoT gateway, and devices exposed to outside by the DMZ function or Port Forwarding function of router, specific protocol for IoT services was used and the devices show a response when services about related protocol are required from outside. From internet search engine for IoT devices, IP addresses are inspected on the basis of protocol mainly used for IoT devices and then IP addresses showing a response are maintained as database, so that users can utilize related information. Specially, IoT devices using HTTP and HTTPS protocol, which are used at usual web server, are easily searched at usual search engines like Google as well as search engine for the sole IoT devices. Ill-intentioned attackers get the IP addresses of vulnerable devices from search engine and try to attack the devices. The purpose of this study is to find the problems arisen when HTTP, HTTPS, CoAP, SOAP, and RestFUL protocols used for IoT devices are detected by search engine and are maintained as database, and to seek the solution for the problems. In particular, when the user ID and password of IoT devices set by manufacturing factory are still same or the already known vulnerabilities of IoT devices are not patched, the dangerousness of the IoT devices and its related solution were found in this study.