• KIPS Transactions on Computer and Communication Systems
• /
• v.10 no.9
• /
• pp.235-242
• /
• 2021

Most data scrambling schemes generate pure random codes. Unlike these schemes, we propose a variable density scrambling scheme (VDSC) that differentiates densities of generated codes. First, we describe conditions and methods to translate plain codes to cipher codes with different densities. Then we apply the VDSC to flash memory such that preferred cell states occur more than others. To restrain error rate, specifically, the VDSC controls code densities so as to increase the ratio of center state among all possible cell states in flash memory. Scrambling experiments of data in Windows and Linux systems show that the VDSC increases the ratio of cells having near-center states in flash memory.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2000.04a
• /
• pp.103-106
• /
• 2000

본 논문에서는 키 교환 단계없이 비대칭키 암호 알고리즘을 사용하여 대량의 메시지를 암호화하여 전송하는 기법을 제안한다. 제안된 기법은 전체 메시지를 스크램블링한 후 스크램블링된 메시지의 일부분만을 공개키 암호 알고리즘을 사용하여 암호화하여 전송한다. 스크램블링 함수로 신상욱[3] 등에 의해 제안된 해쉬함수를 사용한 all-or-nothing 변환을 이용한다. 그리고 제안된 기법에 약간의 추가적인 오버헤드를 부가하여 디지털 서명까지 제공하는 기법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.277-279
• /
• 2013

스크램블링(Scrambling)은 네트워크에서 영상을 전송할 때 보안을 위해 데이터를 특정한 키에 의해 암호화 하여 전송함으로써, 수신자만이 원본 영상으로 복원할 수 있도록 하는 기술이다. 스크램블링은 전송에서 TDES, AES 뿐만아닌 SEED, AIRA의 암호화 알고리즘을 사용한다. 이 경우 암복호화에 많은 시간이 소요되어 실시간 전송환경에서는 전송속도 저하에 따른 QoS 문제가 발생한다. 이와 같은 문제를 해결하기 위해 기존 연구에서는 속도가 빠른 해쉬 함수를 이용하여 스크램블링 암호화 하는 기법을 제안하였다. 하지만 원본 이미지의 일부가 노출될 경우 이후 원본프레임이 노출될 수 있는 문제점을 가지고 있다. 본 논문에서는 이러한 문제점을 방지하기 위해 다중 해쉬 키 프레임을 이용한 Multi Hash key Frame based Scrambling Encryption 알고리즘을 제안한다. 성능평가에서는 제안하는 스크램블링 기법에 대한 암복호화 비용과 성능을 측정하였으며, 기존기법과 비교하였을 때 원본 노출로 인한 대입공격 취약성 부분을 기존 해쉬 함수의 보안 안전성만큼 향상시켰다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39A no.6
• /
• pp.303-309
• /
• 2014

Chaos communication system can improve a system security due to characteristics of non-periodic, non-predictability, broadband signal and easy implementation. Also, chaos signal is sensitive to initial conditions of chaos map. By these reasons, security of chaos communication system is superior to digital communication system. BER performance of COOK modulation system is better than other chaos modulation systems, even if COOK modulation system uses an asynchronous receiver. However, security and safety of COOK modulated signal are worse than other chaos modulation systems, because information bits can be easily predicted from COOK modulated signal. In this paper, for security improvement of COOK modulated signal, we propose a novel Scrambling COOK modulation system by applying the scrambling method. Conventional COOK modulated signal can be predicted, because chaos signal is generated when data is only 1. However, proposed system cannot be predicted, because chaos signal is generated when data is 0 or 1. Therefore, security and safety of transmitted signal in scrambling COOK modulation system is superior to conventional COOK modulation system.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.42 no.2 s.302
• /
• pp.59-68
• /
• 2005

The amount of digitalized contents has been rapidly increased, but the main distribution channel of them is Internet which is easily accessible. Therefore 'security' necessarily arises as one of the most important issues and the method of protecting contents becomes a major research topic as much as data coding techniques. In recent years, many developers have studied on techniques that allow only authorized person to access contents. Among them the scrambling method is one of well-known security techniques. In this paper, we propose a simple and effective digital video scrambling method which utilizes the intra block properties of a recent video coding technique, H.264. Since intra prediction modes are adopted in H.264 standard, it is easy to scramble a video sequence with modification of the intra prediction modes. In addition to its simplicity, the proposed method does not increase bit rate after scrambling. The inter blocks are also distorted by scrambling intra blocks only. This paper introduces a new digital video scrambling method and verifies its effectiveness through simulation.

• KIPS Transactions on Computer and Communication Systems
• /
• v.1 no.3
• /
• pp.187-192
• /
• 2012

This paper describes efficient H.264/AVC video scrambling methods for digital rights management. The proposed scrambling methods are to scramble level and suffix in entropy encoding and MVD in motion estimation of the H.264 video compression process. Other scrambling methods have been proposed but they degrade the compression efficiency or make it difficult to achieve real-time processing due to the large amount of computational efforts. Since the proposed scrambling methods resolve the drawbacks of other approaches, they do not cause image distortion and the original compression efficiency is maintained. We verified our scrambling methods and evaluated the performance by conducting several experiments with H.264 reference program. Finally, we implemented video player system using USB dongle in order to apply the proposed scrambling/descrambling methods to H.264 video compression.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.10a
• /
• pp.85-88
• /
• 2008

본 논문에서는 집적 영상 (integral imaging) 방식과 픽셀 스크램블링 (pixel scrambling) 기술을 이용한 광 영상 암호화 (optical image encryption) 방법을 제안한다. 제안한 방법의 부호화 과정에서는 먼저 입력영상을 여러 개의 작은 사이즈의 블록으로 나누어 픽셀 스크램블링을 한 다음 집적 영상 기술을 이용하여 요소 영상(elemental image)을 생성하고, 이 영상의 안정성을 위하여 2차 픽셀 스크램블링을 수행하여 최종 암호화된 영상을 얻는다. 그리고 복호화 과정에서는 암호화된 영상에 광학적인 집적 영상 복원 기법과 역 픽셀 스크램블링 방법을 사용하여 원 영상을 복원한다. 제안하는 광 암호화 방법에 대해서 크로핑과 같은 데이터 손실 및 노이즈에 대한 컴퓨터 적으로 모의실험을 수행하여 강인성과 유용성을 보였다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.1
• /
• pp.65-72
• /
• 2015

AMI / HDB-3 method used a scrambling technique is used primarily for long distance data transmission line encoding. In this paper, information communication code standard (KS X 1001; 2014 confirmation), as defined in Hangul Character Code HDLC Flag bit or character stuffing at the data link layer and physical layer with respect to the code set for Hangul AMI / HDB-3 the code set for the new system to increase the data transmission efficiency Hangul consonant and vowel tables presented in terms of scrambling. The result of the existing system and the code set ($4{\times}4$) bit source coding rules for comparing the frequency of use Hangul consonant and vowel tables and statistics showed that about 22.01% of the data processing efficiency is improved.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.4C
• /
• pp.380-387
• /
• 2009

In this paper, optical image encryption using integral imaging and pixel-scrambling technologies is proposed. In the encryption process, we use pixel scrambling to change the order of subsections into which the cover image is divided, and the utilize the integral imaging scheme to obtain the elemental image from the scrambled image. In order to achieve higher security, we reuse pixel scrambling to the elemental image. In the decryption process, we employ optical integral imaging reconstruction technique and inverse pixel scrambling methode. Computer simulation results prove the feasibility of the proposed method and robustness against data loss and noise.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.6 no.5
• /
• pp.657-664
• /
• 2011

This paper proposes the revised ASCII code. The study started with consideration whether the ASCII code is proper or not in the side of the transmission efficiency in data communications. In data communications, when the consecutive "0" bits from the information devices input into the line coder, its consecutive "0" bits are scrambled to the predetermined patterns not to the consecutive "0" signal. The paper used to study with the statistical data for the frequency of the letters of the alphabets and the proposed rule of characters coding in reference. As a result of the study, when the proposed ASCII code is applied, the operation efficiency of the scrambler in the line coder is improved upto average 30%.