• Review of KIISC
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• v.9 no.4
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• pp.81-87
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• 1999

Density'(밀도)가 비교적 높은 Chor-Rivest 암호체계는 기존의 LLL과 같은 유형의 공격법이 아니라 비밀키를 일부 찾아내므로 써 공격이 가능하고 '98 Crypto에 처음 발표되 고 '99 Crypto에 그의 공격법과 안전성이 논의된 hidden subset sum problem은 기존의 knapsack 유형의 암호체계와 마찬가지로 밀도가 높을 때 안전하고 밀도가 낮으면 공격이 가능하다 따라서 두 암호체계의 접목을 통하여 안전한 암호체계가 가능한지를 살펴보는 것 도 의미가 있을 것이다, 결론적으로 이야기하면 두암호체계의 접목은 여러 가지 문제점을 포함하고 있기 때문에 어려우리라 생각된다. 제1장에서의 hidden subset sum problem을 살 펴보고 제2장에서는 Chor-Rivest 암호체계를 분석해보고 제 3장에서 Chor-Rivest 암호체계 의 변경 가능한 요소들을 살펴보고 제4장에서 Chor-Rivest 암호체계에 hidden subset sum problem의 활용이 가능한지를 살펴보도록한다. knapsack 유형의 암호체계들중 비교적 최근 까지 안전하다고 하는 암호체계들을 살펴봄으로써 이런 유형들의 개발여부를 생각해 볼수 있는 기회가 되리라 기대된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.133-136
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• 2000

이 논문에서는 먼저 소수성 시험 알고리즘의 기본 개념이 되는 Fermat 의 정리를 살펴본다. 그리고, 가장 널리 사용되고 구현이 용이한 소수성 시험 알고리즘인 Rabin-Miller 및 Rivest 알고리즘을 살펴보고, 이들 알고리즘의 수행 시간을 분석한다. 또한, Rivest 가 제시한 연구 결과를 바탕으로 소수성시험 방법의 수행성능 향상 방안을 고려함으로써, Rivest 알고리즘을 효율적으로 구현하여 암호 시스템 등의 응용에 적용할 수 있도록 개선 방안을 제시한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.1 no.1
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• pp.16-28
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• 1991

Knapsack public-key cryptosystems are based on the knapsack problem which is NP-complete. aii of the knapsack problem, are known to be insecure. However, the Chor and Rivest knapsack cryptosystem based on arithmetic in finite field is secure against all known cryptosystem based on arithmetic in a finite field is secure against all known cryptanalytic attacks. We suggest a new msthod of attack on knapsack cryptosystem which is based on the relaxation of a quadratic 0-1 integer optimization problem. We show that under certain condirions some bits of the solution of knapsack problem can be determined by using persistency property of linear relaxation. Also we propose a new Chor-Rivest system, this new cryptosystem reduces the number of calculation of discrete logarithms which are necessary for the implemention in a multi-user system.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.369-376
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• 2018

This paper presents an android-based implementation of real-time remote monitoring system for industrial gas turbines. The use of remote monitoring techniques can be beneficial in terms of not only the reduction of monitoring cost but also the earlier detection of abnormal status. In order to achieve the ability of protecting sensitive information from unauthorized persons, the proposed system supports secure transmissions using the RSA(Rivest Shamir Adleman) algorithm. In the event of abnormal situation on the gas turbine, the remote monitoring system generates an alarm to attract the user's attention by exploiting a push-message technique. The proposed system has been verified through a series of experiments with an experimental setup including a virtual data generator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1276-1281
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• 2002

Bellare and Rivest proposed the translucent cryptography which was a kind of key recovery system. Translucent cryptography is a system in which the third party can recover encrypted message with the probability p(0$\leq$p$\leq$1). The key recovery agency doesn't need to store the user's private key in advance. The balance between key recovery agency and user can be controlled by the value of p. For example, if p is set to be 0.4 then the key recovery agency can recover 40 out of 100 encrypted messages. In this paper, we show that user can easily deceive the key recovery agency in the translucent cryptography. Then we propose the solution of this problem.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.45-47
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• 1998

본 연구에서는 로버트 메이의 논리차이방정식(Logistic difference equation)을 이용하여 ASCII코드로 만들어진 문서를 암호화 할 수 있도록 하는 카오스 LCC(Logistic Chaos Cryptosystem)을 제안한다. 카오스를 이용한 암호화 기법은 기존의 암호화 기법으로 알려진 DES(Data Encrypion Standard)나 RSA(Rivest,Shamir,Adleman)등과는 비교되는 기법으로 초기 조건에 민감한 카오스의 특징을 이용하였다. 실험결과 제안된 LCC 기법을 통해 암호문은 카오스적으로 표현되었으며, 원문과 암호문 사이에 어떠한 관련성도 찾아 볼수 없었다. 향후 안전성이나 처리속도에 대한 검증과 표준화 문제 및 멀티미디어 자료등에 대한 암호화 기법을 계속 연구해야 할 것이다.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.579-586
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• 2001

Digital watermarking is to embed imperceptible mark into image, video, audio, and text data to prevent the illegal copy of multimedia data. arbitrary modification, and also illegal sales of the copies without agreement of copyright ownership. In this paper, we study for the embedding and extraction of watermark key using wavelet in the luminance signal in order to implement the system to protect the copyright for image MPEG. First, the original image is analyzed into frequency domain by discrete wavelet transform. The RSA(Rivest, Shamir, Aldeman) public key of the coded target is RUN parameter of VLD(variable length coding). Because the high relationship among the adjacent RUN parameters effect the whole image, it prevents non-authorizer not to possess private key from behaving illegally. The Results show that the proposed method provides better moving picture and the distortion more key of insert than direct coded method on low-frequency domain based DCT.

• Journal of IKEEE
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• v.24 no.3
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• pp.791-796
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• 2020

In this paper, "Q-Bone", a 3^rd generation blockchain platform with enhanced security and flexibility, was developed. As a 3^rd generation blockchain platform, it exploits BP (block producer) to increase processing speed. It has many advantages as follows. It improves both security and speed by mixing RSA (Rivest-Shamir-Adleman) and AES (advanced encryption standard). It improves flexibility by exploiting gateway to convert between apps and blockchain with different programming language. It increases processing speed by combining whole transactions into one block and distribute it when too many transactions occur. It improves search speed by inserting sequence hash into transaction data. It was implemented and applied to pet communication service and academy-instructor-student matching service, and it was verified to work correctly and effectively. Its processing speed is 3,357 transactions/second, which shows excellent performance.

• Journal of IKEEE
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• v.9 no.1 s.16
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• pp.31-39
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• 2005

This paper presented new biometrics data transfer model, and use MD5 (Message Digest5) and RSA (Ron Rivest, Adi Shamir, Len Adleman) algorithm to improve biometrics data's security. So, did so that can run user authentication more safely. That is, do so that may input fingerprint among biometrics through client, and transmit processed fingerprint to server. When fingerprint information is transmitted, it uses MD5 algorithm to solve problem that get seized unlawful living body information from outside and information does Digest. And did to pass through process that transmit again this by RSA method. Also, experimented general text data and living body data that is not encoded, transmission speed and security of living body data that encoding and transmit each comparison. By running user authentication through such improved method, is expected to be applied in several. fields by method to simplify certification procedure and is little more correct and stable.

• Convergence Security Journal
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• v.18 no.4
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• pp.27-33
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• 2018

Stream cipher is an one-time-pad type encryption algorithm that encrypt plaintext using simple operation such as XOR with random stream of bits (or characters) as symmetric key and its security depends on the randomness of used stream. Therefore we can design more secure stream cipher algorithm by using mathematical analysis of the stream such as period, linear complexity, non-linearity, correlation-immunity, etc. The key stream in stream cipher is generated in linear feedback shift register(LFSR) having characteristic polynomial. The primitive polynomial is the characteristic polynomial which has the best security property. It is used widely not only in stream cipher but also in SEED, a block cipher using 8-degree primitive polynomial, and in Chor-Rivest(CR) cipher, a public-key cryptosystem using 24-degree primitive polynomial. In this paper we present the concept and various properties of primitive polynomials in Galois field and prove the theorem finding the number of irreducible polynomials and primitive polynomials over $F_p$ when p is larger than 2. This kind of research can be the foundation of finding primitive polynomials of higher security and developing new cipher algorithms using them.