• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.755-759
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• 2012

In this paper, it is about random number generator, which is based on hardware is utilized in medical science and game area. The Intel presents guideline of security level about hardware based true random number generator. At hardware based random number generator, the various test items, that are included in test suits as NIST statistical test, FIPS140-1, is applied. In this paper, it experiments about degree extent of randomness variation from filter scheme effects, which is applied in output stream of hardware noise source.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.80-86
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• 2006

In this paper, we propose the PingPong-128(PP-128) keystream generator, based on summation generator. Proposed PingPong-128, a specific cipher of the PingPong Family, takes 128 bits key and 128 bit initial vector, has 258 bit internal state, and achieves a security level of 128 bits. The security analysis of PingPong-128 is presented, including the resistence to known attacks against the summation generator and other clock-controlled generators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.390.1-390
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• 2002

In this study, we investigate the plugging effect on the CE type steam generator tube. The natural frequency and mode shape will be changed due to decrease of the effective mass distribution along the tube. We compared the variation of stability ratio for plugged tube with that fur unplugged one. The natural frequency increased because of removing the cooling water inside the steam generator tube, but the stability ratio decreased inversely because of changing the vibrational mode shape. We also investigated the turbulent excitation effect.

• Journal of applied mathematics & informatics
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• v.7 no.1
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• pp.269-278
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• 2000

A Boolean function generates a binary sequence which is frequently used in a stream cipher. There are number of critical concepts which a Boolean function, as a key stream generator in a stream cipher, satisfies. These are nonlinearity, correlation immunity, balancedness, SAC(strictly avalanche criterion), PC(propagation criterion) and so on. In this paper, we present the algorithms for generating random nonlinear combining functions satisfying given correlation immune order and nonlinearity. These constructions can be applied for designing the key stream generators. We use Microsoft Visual C++6.0 for our program.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.1
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• pp.71-77
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• 2004

It was proved that Hen is an algebraic ,elation of degree [n(l+1]/2] for an (n, 1)-combine. which consists of n LFSRs and l memory bits. For the summation generator with $2^k$ LFSRs which uses k memory bits, we show that there is a non-trivial relation of degree at most $2^k$ using k+1 consecutive outputs. In general, for the summation generator with n LFSRs, we can construct a non-trivial algebraic relation of degree at most 2$^{{2^{[${log}_2$}n]}}$ using [${log}_2$＋1 consecutive outputs.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.83-90
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• 2004

DVB-MHP recommends that NPT(normal play time) be used as the times of stream events. NPT is the local time within an event(TV program). But we found that commercial transport stream (TS) generators and middlewares for DVB-MHP settop boxes are not ready to support the use of NPT by applications. In particular, TS generators do not create NPT reference descriptors needed to reconstruct NPT at the TV receiver. This situation is undesirable because program providers cannot experiment with the idea of synchronized applications. So we have implemented a TS generator that inserts NPT reference descriptors to TS and MyGetNPT API to approximately reconstruct NPT. STC (system time clock) is needed to reconstruct NPT, but Xlets are not allowed to read it. So, we approximate STC by using PCR (program clock reference) and the Java system tune. In this method, the stream generator extrats PCRs from an existing TS and inserts them into null TS packets in the form of MPEG sections, which can be read by Xlets. Because PCRs are displaced into new positions in TS, their values should be adjusted based on the time intervals between the original positions and the new positions. We implemented a synchronized application by using our TS generator and MyGetNPT API, where the task of stream events are to display graphic images. We found that graphic images are displayed where 240 ㎳ from their intended time, where 240ms is a human tolerance for the synchronization skew between graphic image and video.

• Convergence Security Journal
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• v.12 no.4
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• pp.17-23
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• 2012

Recently, the research for cryptographic algorithm, in particular, a stream cipher has been actively conducted for wireless devices as growing use of wireless devices such as smartphone and tablet. LFSR based random number generator is widely used in stream cipher since it has simple architecture and it operates very fast. However, the conventional multi-LFSR RNG (random number generator) suffers from its hardware complexity as well as very closed correlation between the numbers generated. A leap-ahead LFSR was presented to solve these problems. However, it has another disadvantage that the maximum period of the generated random numbers are significantly decreased according to the relationship between the number of the stages of the LFSR and the number of the output bits of the RNG. This paper presents new leap-ahead LFSR architecture to prevent this decrease in the maximum period by applying segmentation technique to the conventional leap-ahead LFSR. The proposed architecture is implemented using VHDL and it is simulated in FPGA using Xilinx ISE 10.1, with a device Virtex 4, XC4VLX15. From the simulation results, the proposed architecture has only 20% hardware complexity but it can increases the maximum period of the generated random numbers by 40% compared to the conventional Leap-ahead archtecture.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.74-82
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• 2004

In digital broadcasting, applications are computer programs executed by the set-top box(TV receiver) , and synchronized applications are those that perform tasks at the specified moments in the underlying video. This paper describes important concepts, standards, and skills needed to implement synchronized applications and explains how to integrate them to implement these applications. This Paper assumes the European data broadcasting standard, DVB-MHP. In DVB-MHP, scheduled stream events are recommended as a means of synchronizing applications with video streams. In this method, the application receives each stream event, and executes the action associated with the stream event at the time specified in the stream event. Commercially available stream generators, i.e., multiplexers, do not generate transport streams that support scheduled stream events. So we used a stream generator implemented in our lab. We implemented a synchronized application where the actions triggered by stream events are to display graphic images. We found that our synchronized application processes scheduled stream events successfully. In our experimentation, the stream events were synchronized with the video and the deviation from the intended time was within 240 ㎳, which is a tolerance for synchronization skew between graphic images and video.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.1036-1046
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• 2016

We propose a primary water stress corrosion cracking (PWSCC) initiation model of Alloy 600 that considers the stress triaxiality factor to apply to finite element analysis. We investigated the correlation between stress triaxiality effects and PWSCC growth behavior in cold-worked Alloy 600 stream generator tubes, and identified an additional stress triaxiality factor that can be added to Garud's PWSCC initiation model. By applying the proposed PWSCC initiation model considering the stress triaxiality factor, PWSCC growth simulations based on the macroscopic phenomenological damage mechanics approach were carried out on the PWSCC growth tests of various cold-worked Alloy 600 steam generator tubes and compact tension specimens. As a result, PWSCC growth behavior results from the finite element prediction are in good agreement with the experimental results.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1011-1014
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• 2004

본 논문에서 제안된 Self_Decimated LM-128 키 수열 발생기(Keystream generator)는 2개의 비트 메모리 합산 수열발생기(summation generator)를 갖는 자체 클럭 조절형 키 수열 발생기(stream cipher)이다. Self_Decimated LM-128은 LM 계열에서 제시된 특수한 암호로 128비트 키와 128비트 초기 벡터 그리고 257 비트의 내부 상태를 가지며 128 비트의 보안 레벨을 유지한다. 알려진 보안 분석의 공격에 대비해서 2-비트 메모리를 이용한 합산 수열발생기와 자체 클럭 조절형 키 수열 발생기를 포함한다.