Earticle

In this article, we compute the order of a general linear group GLn(A) over a finite ring A.

C. Gentry와 A. Silverberg의 Hierarchical ID-based cryptograph $y^{［3］}$서는 계층에서 수신자의 단계가 깊어짐에 따라 암호문의 길이가 선형적으로 증가한다는 문제가 있었다. 본 논문에서는 HIDS(Hierarchical m-based Signature)의 서명값을 활용해 암호문의 길이를 줄이는 새로운 방법을 제안한다.

Hierarchical ID-based Cryptography proposed by C. Gentry and A. Silverberg has the problem that the length of the ciphertext is proportional to the depth of the recipient in the hierarchy. In this paper, we propose the new methods to shorten the length of the ciphertext by using HlDS(Hierarchical ID-based Signature).

Hyperelliptic Curve Cryptosystem (HECC) is well suited for all kinds of embedded processor architectures, where resources such as storage, time, or power are constrained due to short operand sizes. We can construct genus 3 HECC on 54-bit finite fields in order to achieve the same security level as 160-bit ECC or 1024-bit RSA due to the algebraic structure of Hyperelliptic Curve. This paper explores various possible attacks to the discrete logarithm in the Jacobian of a Hyperelliptic Curve (HEC) and addition and doubling of the divisor using explicit formula to speed up the scalar multiplication. Our aim is to develop a cryptosystem that can sign and authenticate documents and encrypt / decrypt messages efficiently for constrained devices in wireless networks. The performance of our proposed cryptosystem is comparable with that of ECC and the security analysis shows that it can resist the major attacks in wireless networks.

To manage the big data in constraint resources has difficulties and challenges. The power and the cost can be saved when the cloud services are used to process and store the data. However, the data includes the personal information that can be sensitive and should be hidden from the others. So we propose the privacy-preserving classification scheme for image data. The pixel-based learning is the scheme that is adapted to the cryptosystem, and is used to classify the encrypted images. Our proposed deep learning model has the convolutional layers that has the same size of the kernel with the block size in the cryptographic algorithm. The experiment results show that it can improve the accuracy on classification of encrypted images, and make it possible to use the private data securely.

행정전자서명(GPKI)은 대한민국 중앙정부, 지방정부, 공공기관 등이 자체행정과 대민서비스를 제공할 때 사용하는 공개키 기반구조로 정보시스템의 인증 및 보안 기능을 수행한다. 현재 행정전자서명에서 사용하는 암호체계는 2000년대 초반에 구축하였으며, 2010년에 한 차례 고도화를 진행한 후 10여 년이 지났다. 지난 10여 년간 암호를 포함하여 정보보안은 많은 변화를 겪어왔으며, 앞으로도 수많은 변화를 맞이하게 될 것이다. 따라서 행정전자서명의 지속 가능한 안전성을 위해서는 현시점에서 암호체계의 안전성을 재검토할 필요가 있다. 이 논문은 행정전자서명 암호체계에 사용된 기술 및 표준의 현황과 안전성을 분석하여, 안전성이 저하된 암호알고리즘을 사용하거나, 폐지 또는 대체된 표준을 참고하는 사례와 안전성 상향을 위해 조정해야 할 파라미터 등을 식별하였다. 그리고 이를 바탕으로 행정전자서명 암호체계 고도화를 위한 암호알고리즘 및 관련 기술의 개편 방향을 제시한다.

Korean Government-PKI (GPKI) is a public-key infrastructure which provides authentication and security functions for information system used by central government, local governments, and public institutions of the Republic of Korea to provide their own administrative and public services. The current cryptosystem of GPKI was established in the early 2000s, and more than ten years have passed since the last improvement in 2010. Over the past decade or so, the information security, including cryptography, has undergone many changes and will continue to face many changes. Therefore, for the sustainable security of GPKI, it is necessary to review the security of the cryptosystem at this point. In this paper, we analyze the current status and the security of technologies and standards used in the system. We identify cryptographic algorithms with degraded security, international standards which are obsoleted or updated, and cryptographic parameters that should be revised for the high security level. And based on this, we make several suggestions on the reorganization of cryptographic algorithms and related technologies for the security enhancement of GPKI.

Recently, as network and computer technologies are growing rapidly, most of business transactions are performed in cyber world. In spite of many advantages. the most concerns in Electronic Commerce are the information security matters, and the cryptosystem has been claimed as one of the proper means to settle this problem. In this paper, a partial encryption/decryption algorithm has been in-troduced to show the efficiency against the conventional method in which all the data are completely encoded. In our proposed scheme, the multimedia data can be efficiently encoded in a short time pro-viding good data security. For example, the MP3 data can be securely protected with 10% encryption in our scheme. Moreover, the shuffling process at the end of partial encryption procedure provides higher level of data security.

The lack of data security in public mobile telecommunication system increases the need for a strong data protection and security mechanisms. Cryptography is considered as one of the key elements that provides security for mobile systems. Signcryption algorithm, which is based on public key cryptography, provides both confidentiality and authenticity in one step. Moreover, hardware implementations of cryptographic algorithms provide scalable solutions to enhance the level of security of the existing hardware. In this paper, we present a case study on using a DSP board to construct a secure communication channel. We use the constructed DSP board as a hardware cryptosystem to increase the security of transmitted data using any mobile communication system. We evaluate the performance by computing the consumed time by encryption/decryption process, while implementing the Schnorr Signcryption scheme on a DSP. Furtheremore, we propose an enhanced model of applying multiple DSP using pipelines and parallelization technique to decrease the consumed time in the whole process.

Nowadays, the increasing requirement for telemedicine services has raised more concerns in real-time medical image encryption. However, traditional block ciphers have been found poorly fit this requirement. Considering this, we propose an efficient cryptosystem for medical image encryption in the present study. Chaos-based permutation-diffusion architecture is adopted, whereas an improved image confusion strategy is developed based on the intrinsic feature of medical images. The improved confusion approach can bring about not only satisfactory permutation performance but also bit distribution balancing effect for medical images. Simulations and extensive security analyses indicate that the proposed cryptosystem provides an efficient approach for real-time secure medical image transmission and storage over public networks.

A quantum public-key cryptosystem without quantum channels between any two users using non-orthogonal states is provided in this paper. Every user keeps a set of quantum particles in non-orthogonal states in a key management center (KMC) as the public key while he or she keeps the states of them as the private key. By the help of KMC users can accomplish secret communication and message authentication. The laws of quantum physics guarantee the unconditional security of this cryptosystem. No entangled states or complex quantum operations are needed. On the other hand there are no quantum channels needed to connecting any two users. So the public-key cryptosystem is easier to carry out and more robust in practice.

This paper firstly briefed the basic concepts of N public key cryptosystem, RS code and QC-LDPC code, and then put forward the cascade cryptosystem with the RS code being the outer code and QC-LDPC code being the internal code. At last, the writer analyzed in detail the security and performance of the N cryptosystem based on double public key, and thus proved its better security and performance than the traditional public key cryptosystem based on error correcting code. In addition, it is also endowed with higher practicability in complex environment.

In this paper, we propose a new finger multi-biometric cryptosystem using feature-level fusion to simultaneously protect multiple templates of fingerprint, finger vein, finger knuckle print and finger shape traits as a single secure sketch. We theoretically analyze the feature-level fusion for finger multi-biometric cryptosystem with respect to their impact on security and recognition accuracy. The comparative experimental results ascertain that finger multi-biometric cryptosystem outperforms the uni-biometric counterparts in terms of verification performance and template security.

The security of node ID assignment scheme is the foundation of solving security problems in structured P2P systems. However, existing researches on the node ID assignment mechanism present one or more following problems: (1) Schemes just only focused on individual attack, but did not comprehensively analyze the security requirements of node ID assignment mechanism. (2) Schemes needed complex certificate management or met key escrow problem. (3) Almost all existing schemes required a trusted center to act as the single signer of node IDs, but it is very hard to find an absolutely trusted node in structured P2P system. As a result, none of existing schemes can prevent the single signer from being compromised or launching active attack. This paper firstly designs a threshold signature scheme based on secret sharing and certificateless public key cryptosystem without paring (CL-PKC-without-P). Based on that, it proposes a node ID assignment protocol which eliminates the three problems listed above. Using secret sharing technology, this protocol is able to resist the active attacks launching by less than t signer, where t is the threshold value. The results of analysis and simulation show that this protocol is more secure, efficient and scalable.

In 1984, Shamir [1] introduced the concept of an identity-based cryptosystem. In this system, each user needs to visit a public key generation (PKG) and identify himself before joining a communication network. Once a user is accepted, the PKG will provide him with a secret key. In this way, if a user wants to communicate with others, he only needs to know the “identity” of his communication partner and the public key of the PKG. There is no public file required in this system. However, Shamir did not succeed in constructing an identity based cryptosystem, but only in constructing an identity-based signature scheme. Meshram and Meshram [5] have proposed an identity-based beta cryptosystem, security under the generalized discrete logarithm problem with distinct discrete exponents in the multiplicative group of finite fields and integer factorization problem. In this paper, we propose some modification in identity-based beta cryptosystem based on generalized discrete logarithm problem with distinct discrete exponents in the multiplicative group of finite fields and integer factorization problem and we consider the security against a conspiracy of some entities in the proposed system and show the possibility of establishing a more secure system.

Public key cryptography is the famous cryptography technique used in many corporate sectors for developing software to provide security services. Hyperelliptic Curve Cryptosystem (HECC) is one of the public key cryptographic technique, an expansion of Elliptic Curve Cryptography which offers the similar level of security compared with other cryptosystems such as RSA, ECC and DSA. HECC supervise the ECC due to shorter operand size. This paper will analysis the performance of HECC over genus curve 2, 3, 4, 5, 6 and compares the result with ECC. It also inspects the use of Hyperelliptic Curve Cryptography technique and affords complete survey on its performance for many applications.

This paper proposes a secure sealed-bid auction schemes which adopt threshold cryptosystem without a third party. In the previous proposed sealed-bid auction schemes, an auctioneer is responsible for opening bids. However, malicious auctioneers can conspire with malicious bidders by revealing all bidding prices before the bid opening stage for bidding optimal bidding price to win the auction. To prevent against this, we decide to eliminate auctioneer from opening phase and involve plural clerks to choose secret keys, and then clerks distribute public keys to each other. On the bid opening phase, the clerks can cooperate with each other to open the bids without an auctioneer by using Pedersen’s protocol and Lagrange interpolating polynomial. Hence, an auctioneer is only responsible for verifying user’s identification and checking whether bids are valid or not. Furthermore, for enhancing security in our schemes, we utilize a hardware framework entitled “Untraceable Decryptor” to make all bids pass through it when the bids are transferred to clerks.

E-Passports are issued to the citizens by many countries with biometric data like face, fingerprint and iris for foolproof identification. A first generation standard for E-Passport was proposed by International Civil Aviation Organisation. Due to security flaws in the proposed one, second generation standards with Extended Access Control mechanism was developed. To improve the security of E-Passport many proposals are being discussed. This paper suggests a new authentication protocol using Customized Elliptic Curve Cryptography to improve the reliability of E-Passport.

A proxy signature allows a designated person, called a proxy signer, to sign the message on behalf of the original signer. Proxy signatures are very useful tools when one needs to delegate his/her signing capability to other party. A number of proxy signature schemes have been proposed and succeeded for proxy delegations, but the schemes are in defective in proxy revocations. In this paper, we propose proxy signature scheme based on RSA cryptosystem. Our scheme does not consider proxy revocation mechanism, but it is efficient than the existing RSA-based schemes.

본 논문에는 저전력 AES(Advanced Encryption Standard) 암호시스템을 구현하기 위한 합성체 기반의 경량 S-Box 구조 설계를 제안한다. 제안한 방법에서는 GF(((22)2)2) 상에서 사용면적 및 처리속도의 개선을 위해서 x2, λ, 그리고 GF((22)2) 등 3개의 모듈을 1개의 모듈로 통합한 단순 구조로 설계한다. 설계된 AES S-Box는 Verilog-HDL를 기반으로 하여 구조적 모델링을 하였으며, Xilinx ISE 14.7툴 상에서 Spartan 3s1500l FPGA 소자를 타켓으로 하여 논리합성을 수행하였다. 논리적인 동작을 검증을 위한 시뮬레이션은 Modelsim 10.3 툴을 이용하였으며, 시뮬레이션 결과를 통하여 설계된 S-Box가 정확히 동작함을 확인하였다.

In this paper, the design of lightweight S-Box structure for implementing a low power AES cryptosystem based on composite field. In this approach, the S-Box is designed as a simple structure by which the three modules of x2, λ, and GF((22)2) merge into one module for improving the usable area and processing speed on GF(((22)2)2). The designed AES S-Box is modelled in Veilog-HDL at structural level, and a logic synthesis is also performed through the use of Xilinx ISE 14.7 tool, where Spartan 3s1500l is used as a target FPGA device. It is shown that the designed S-Box is correctly operated through simulation result, where ModelSim 10.3. is used for performing timing simulation.