• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.627-632
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• 2005

Almost all network systems provide an authentication mechanism based on user ID and password. In such system, it is easy to obtain the user password using a sniffer program with illegal eavesdropping. The one-time password and challenge-response method are useful authentication schemes that protect the user passwords against eavesdropping. In client/ server environments, the one-time password scheme using time is especially useful because it solves the synchronization problem. It is the stability that is based on Square Root problem, and we would like to suggest OPI(One Pass Identification), enhancing the stability for all of the well-known attacks by now including Free-playing attack, off-line Literal attack, Server and so on. OPI does not need to create the special key to read the password. OPI is very excellent in identifying the approved person within a very short time.

• Journal of KIISE:Information Networking
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• v.31 no.3
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• pp.252-258
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• 2004

In this paper, we propose a new authenticated key exchange protocol in which client and sever can mutually authenticate and establish a session key over an insecure channel using only a human memorable password. The proposed protocol is based on Diffie-Hellman scheme and has many of desirable security attributes: It resists off-line dictionary attacks mounted by either Passive or active adversaries over network, allowing low-entropy Passwords to be used safely. It also offers perfect forward secrecy, which protects past sessions when passwords are compromised. In particular, the advantage of our scheme is that it is secure against an impersonation attack, even if a server's password file is exposed to an adversary. The proposed scheme here shows that it has better performance when compared to the previous notable password-based key exchange methods.

• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.525-535
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• 2005

A password-based authenticated tripartite key exchange protocol based on A. Joux's protocol was proposed. By using encryption scheme with shared password, we can resolve man-in-the-middle attack and lack of authentication problems. We also suggested a scheme to avoid the offline dictionary attack to which symmetric encryption schemes are vulnerable. The proposed protocol does not require a trusted party which is required in certificate or identity based authentication schemes. Therefore in a ad hoc network which is difficult to install network infrastructure, the proposed protocol would be very useful. The proposed protocol is more efficient in computation aspect than any existing password-based authenticated tripartite key exchange protocols. When it is used as a base line protocol of tree based group key exchange protocol, the computational weak points of the proposed protocol are compensated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.81-86
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• 2009

Almost all network systems provide an authentication mechanism based on user ID and password. In such system, it is easy to obtain the user password using a sniffer program with illegal eavesdropping. The one-time password and challenge-response method are useful authentication schemes that protect the user passwords against eavesdropping. In client/server environments, the one-time password scheme using time is especially useful because it solves the synchronization problem. In this paper, we propose a new identification scheme One Pass Identification. The security of Password base System is based on the square root problem, and Password base System is secure against the well known attacks including pre-play attack, off-line dictionary attack and server comprise. A number of pass of Password base System is one, and Password base System processes the password and does not need the key. We think that Password base System is excellent for the consuming time to verify the prover.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8C
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• pp.697-702
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• 2012

In 2011, C.-T. Li et al. proposed a secure user authentication scheme, which is an improvement over Kim et al.'s scheme to resolve several security flaws such as off-line password guessing attack and masquerading attack. C.-T. Li et al. claimed that their scheme prevents smart card security related attacks. Moreover, it provides mutual authentication and session key establishment. However, we found that their scheme is vulnerable to password guessing attack through password change phase, smart card forgery attack and stolen verifier attack. Moreover, C.-T. Li et al.'s scheme is not secure against password guessing attack as they claimed. In this paper, we also point out that their scheme is not practical to use.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.45-53
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• 2018

Recently, studies about bilingual word embedding have been gaining much attention. However, bilingual word embedding with Korean is not actively pursued due to the difficulty in obtaining a sizable, high quality corpus. Local embeddings that can be applied to specific domains are relatively rare. Additionally, multi-word vocabulary is problematic due to the lack of one-to-one word-level correspondence in translation pairs. In this paper, we crawl 868,163 paragraphs from a Korean-English law corpus and propose three mapping strategies for word embedding. These strategies address the aforementioned issues including multi-word translation and improve translation pair quality on paragraph-aligned data. We demonstrate a twofold increase in translation pair quality compared to the global bilingual word embedding baseline.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.91-98
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• 2012

A group key exchange (GKE) protocol is designed to allow a group of parties communicating over a public network to establish a common secret key. As group-oriented applications gain popularity over the Internet, a number of GKE protocols have been suggested to provide those applications with a secure multicast channel. Among the many protocols is Yi et al.'s password-based GKE protocol in which each participant is assumed to hold their individual password registered with a trusted server. A fundamental requirement for password-based key exchange is security against off-line dictionary attacks. However, Yi et al.'s protocol fails to meet the requirement. In this paper, we report this security problem with Yi et al.'s protocol and show how to solve it.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.112-120
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• 2013

In this paper, we propose high-performance H.264/AVC CAVLC encoder for UD video real time processing. Statistical values are obtained in one cycle through the parallel arithmetic and logical operations, using non-zero bit stream which represents zero coefficient or non-zero coefficient. To encode codeword per one cycle, we remove recursive operation in level encoding through parallel comparison for coefficient and escape value. In oder to implement high-speed circuit, proposed CAVLC encoder is designed in two-stage {statical scan, codeword encoding} pipeline. Reducing the encoding table, the arithmetic unit is used to encode non-coefficient and to calculate the codeword. The proposed architecture was simulated in 0.13um standard cell library. The gate count is 33.4Kgates. The architecture can support Ultra Definition Video ($3840{\times}2160$) at 100 frames per second by running at 100MHz.

• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.133-138
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• 2009

Recently Lin et al. proposed the remote user authentication scheme using smart cards. But the proposed scheme has not been satisfied security requirements considering in the user authentication scheme using the password based smart card. In this paper, we showed that he can get the user's password using the off-line password guessing attack on the scheme when the adversary steals the user's smart card and extracts the information in the smart card. Also, we proposed the seven security requirements for evaluating remote user authentication schemes using smart card. As a result of analysis, in Lin et al's scheme we have found the deficiencies of security requirements. So we suggest the improved scheme, the mutual authentication scheme that does not store the user's password verifier in server and can authenticate each other at the same time between the user and server.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.117-123
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• 2013

By exploiting the regular read and write access patterns of embedded SRAM memories inside Viterbi decoder, the memory architecture can be efficiently modified to reduce the power consumption of write operation. According to the experimental results with 65nm CMOS process, the proposed embedded memory used for Viterbi decoder achieves 30.84% of power savings with 8.92% of area overhead compared to the conventional embedded SRAM approaches.