• Convergence Security Journal
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• v.8 no.1
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• pp.79-90
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• 2008

Services over SIP protocol are anticipated to be commonly used services in our usual life. Especially, presence is a new feature in SIP-based services and actually entities' presence information has close relationship with privacy of them. Also, the XCAP-based authorization is accepted as a highly probable method to protect privacy of entities in SIP-based services. However, there is no proposed presence service model except IM service and it's hard to find the reference model that shows a way how we can apply XCAP-based authorization method into presence service. In this paper, we proposed new presence service model which is applicable to the VoIP service. We suggested presence service model which is making use of XCAP-based authorization to get protection of privacy in a organized way and the suggested model's each messaging steps were reviewed using concrete examples. Contributions of this work is in the suggestion of privacy-aware presence service using XCAP-based authorization and its verification of its each messaging step.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.147-156
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• 2009

This paper proposes a SRTP key exchange scheme using split transfer of divided RSA public key in SIP-based VoIP environment without PKI. The existing schemes are hard to apply to real VoIP environment, because they require a PKI and certificates in the end devices. But in case of ZRTP. which is one of existing schemes, it's able to exchange SRTP Key securely without PKI, but it is inconvenient since it needs user's involvement. To solve these problems, the proposed scheme will split RSA public key and transmit them to SIP signaling secession and media secession respectively. It can defend effectively possible Man-in-The-Middle attacks, and it is also able to exchange the SRTP key without the user's involvement. Besides, it meets the requirements for security of SRTP key exchange. Therefore, it's easy to apply to real VoIP environment that is not available to construct PKL.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1297-1304
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• 2011

SIP(Session Initiation Protocol) has some security vulnerability because it works on the Internet. Therefore, the proxy server can be affected by the flooding attack such as DoS and service interruption. However, traditional schemes to corresponding Denial of Service attacks have some limitation. These schemes have high complexity and cannot protect to the variety of Denial of Service attack. In this paper, we newly define the normal user who makes a normal session observed by verifier module. Our method provides continuous service to the normal users in the various situations of Denial of Service attack as constructing a whitelist using normal user information. Various types of attack/normal traffic are modeled by using OPNET simulator to verify our scheme. The simulation results show that our proposed scheme can prevent DoS attack and achieve a low false rate and fast searching time.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.179-192
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• 2024

macOS presents challenges for memory data acquisition due to its proprietary system architecture, closed-source kernel, and security features such as System Integrity Protection (SIP), which are exclusive to Apple's product line. Consequently, conventional memory acquisition tools are often ineffective or require system rebooting. This paper analyzes the status and limitations of existing memory forensics research and tools related to macOS. We investigate methods for memory acquisition and analysis across various macOS versions. Our findings include the development of a practical memory acquisition and analysis process for digital forensic investigations utilizing OSXPmem and dd tools for memory acquisition without system rebooting, and Volatility 2, 3 for memory data analysis.

• Journal of KIISE:Information Networking
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• v.37 no.4
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• pp.263-271
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• 2010

SIP/RTP-based VoIP services are being popular. Recently, however, VoIP anomaly traffic such as delay, interference and termination of call establishment, and degradation of voice quality has been reported. An attacker could intercept a packet, and obtain user and header information so as to generate an anomaly traffic, because most Korean VoIP applications do not use standard security protocols. In this paper, we propose three VoIP anomaly traffic generation methods for CANCEL;BYE DoS and RTP flooding, and a detection method through flow-based traffic measurement. From our experiments, we showed that 97% of anomaly traffic could be detected in real commercial VoIP networks in Korea.

• Journal of KIISE:Information Networking
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• v.34 no.2
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• pp.134-142
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• 2007

Several mobility supporting protocols have been proposed across OSI reference layers. Each protocol has similar or different characteristics based on its operating layer which affect a handover latency. In this paper, we analyze handover performance of most representative protocols in each layer. For analysis, we use SUBNET model based Markovian model and movement model. In result, difference of protocol handover latency is not occurred by DAD but also by security, movement detection, message processing time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.942-949
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• 2006

The VoIP(Voice over IP) has been worldwide used and already put to practical use in many fields. However, it is needed to ensure secret of VoIP call in a special situation. It is relatively difficult to eavesdrop the commonly used PSTN in that it is connected with 1:1 circuit. However, it is difficult to ensure the secret of call on Internet because many users can connect to the Internet at the same time. Therefore, this paper suggests a new model of Internet telephone for eavesdrop prevention enabling VoIP(using SIP protocol) to use the VPN protocol and establish the probability of practical use comparing it with Internet telephone.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.175-184
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• 2022

Voice over Internet Protocol (VoIP) has grown in popularity as a low-cost, flexible alternative to the classic public switched telephone network (PSTN) that offers advanced digital features. However, additional security vulnerabilities are introduced by the VoIP system's flexibility and the convergence of voice and data networks. These additional challenges add to the normal security challenges that a VoIP system's underlying IP data network infrastructure confront. As a result, the VoIP network adds to the complexity of the security assurance task faced by businesses that use this technology. It's time to start documenting the many security risks that a VoIP infrastructure can face, as well as analyzing the difficulties and solutions that could help guide future efforts in research & development. We discuss and investigate the challenges and requirements of VoIP security in this research. Following a thorough examination of security challenges, we concentrate on VoIP system threats, which are critical for present and future VoIP deployments. Then, towards the end of this paper, some future study directions are suggested. This article intends to guide future scholars and provide them with useful guidance.

• Journal of the Korea Convergence Society
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• v.1 no.1
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• pp.93-100
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• 2010

Diverse kind of attack using the vulnerability of user authentication on Internet service is announced recently. Especially, security accidents on the Internet banking service and Internet telephony service(SIP) are increased rapidly. Attack skills are also evolved into intelligent mechanism. Therefore, more enhanced authentication mechanism is required on existing Internet banking and telephone services for preventing those kinds of attacks using personal identity information such as biometric data. In this research, the proposed B-OTP mechanism can be used to enhance security on a user authentication procedure by combining biometric data with existing OTP mechanism. As a result, the security on internet banking and Internet telephone service will be more improved by using proposed B-OTP mechanism.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.4
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• pp.117-125
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• 2018

Recently, VoIP technology is widely used in our daily life. Even VoIP has become a technology that can be easily accessed from services such as home phone as well as KakaoTalk.[1] Most of these Internet telephones use the RTP protocol. However, there is a vulnerability that the audio data of users can be intercepted through packet sniffing in the RTP protocol. So we want to create a tool to check the security level of a VoIP network using the RTP protocol. To do so, we capture data packet from and to these VoIP networks. For this purpose, we first configure a virtual VoIP network using Raspberry Pi and show the security vulnerability by applying our developed sniffing tool to the VoIP network. We will then analyze the captured packets and extract meaningful information from the analyzed data using the Google Speech API. Finally, we will address the causes of these vulnerabilities and possible solutions to address them.