Cryptanalysis of an image encryption scheme based on the Hill cipher

This paper studies the security of an image encryption scheme based on the Hill cipher （Ismail et al., 2006） and reports its following problems： （1） There is a simple necessary and sufficient condition that makes a number of secret keys invalid; （2） It is insensitive to the change of the secret key; （3） It is insensitive to the change of the plain-image; （4） It can be broken with only one known/chosen plaintext; （5） It has some other minor defects. The proposed cryptanalysis discourages any use of the scheme in practice.     

一种基于PKI的密钥

Internet key exchange (IKE) is an automated key exchange mechanism that is used to facilitate the transfer of IPSec security associations (SAs). Public key infrastructure (PKI) is considered as a key element for providing security to new distributed communication networks and services. In this paper, we concentrate on the properties of the protocol of Phase 1 IKE. After investigating IKE protocol and PKI technology, we combine IKE protocol and PKI and present an implementation scheme of the IKE based on PKI. Then, we give a logic analysis of the proposed protocol with the BAN-logic and discuss the security of the protocol. The result indicates that the protocol is correct and satisfies the security requirements of Internet key exchange.     

How to repair the Hill cipher

INTRODUCTION Owing to the advance in network technology, information security is an increasingly important problem. Popular application of multimedia tech- nology and increasingly transmission ability of net- work gradually leads us to acquire information di- rectly and clearly through images. Hence, data secu- rity has become a critical and imperative issue. Hill cipher is a block cipher that has several advantages such as disguising letter frequencies of the plaintext, its simplicity be…     

Certificateless key-insulated signature without random oracles

Leakage of the private key has become a serious problem of menacing the cryptosystem security. To reduce the underlying danger induced by private key leakage, Dodis et al.（2003） proposed the first key-insulated signature scheme. To handle issues concerning the private key leakage in certificateless signature schemes, we devise the first certificateless key-insulated signature scheme. Our scheme applies the key-insulated mechanism to certificateless cryptography, one with neither certificate nor key escrow. We incorporate Waters （2005）＇s signature scheme, Paterson and Schuldt （2006）＇s identity-based signature scheme, and Liu et al.（2007）＇s certificateless signature scheme to obtain a certificateless key-insulated signature scheme. Our scheme has two desirable properties. First, its security can be proved under the non-pairing-based generalized bilinear Diffie-Hellman （NGBDH） conjecture, without utilizing the random oracle model; second, it solves the key escrow problem in identity-based key-insulated signatures.     

Secure and efficient multi-message and multi-receiver ID-based signcryption for rekeying in ad hoc networks

In this paper, the security technology of ad hoc networks is studied.To improve the previous multi-receiver signcryption schemes, an ID-based multi-message and multi-receiver signcryption scheme for rekeying in ad hoc networks is proposed.In this scheme, a sender can simultaneously signcrypt n messeges for n receivers, and a receiver can unsigncrypt the ciphertext to get his message with his own private key.An analysis of this scheme indicates that it achieves authenticity and confidentiality in the random oracle model while being of lower computation and communication overhead.Finally, for the application of our scheme in ad hoc, a threshold key updating protocol for ad hoc networks is given.     

Non-interactive identity-based threshold signature scheme without random oracles

A （t, n） threshold signature scheme distributes the secret key and hence the signing ability to n players in a way that any set of t＋ 1 or more honest players can collaborate to sign, while any set of t players cannot. In this paper we propose an identity-based threshold signature （IBTHS） scheme from bilinear pairings. The signing phase of our scheme is non-interactive, meaning that the signing players do not need to talk to each other. We prove our scheme secure （i.e., unforgeable and robust） in the standard model （i.e., without random oracles）. No earlier proposed IBTHS scheme achieved even one of the features of being non-interactive （in the signing phase） and secure in the standard model.     

Improvement of Laih and Yen's multisignature scheme

A new attack is proposed to show that a specified group of verifiers can cooperate to forge the signature for any message by secret key substitution due to the leaked secret key or by the group public key adjustment because of the renewed members. This paper presents the improvement scheme which overcomes the security weakness of Laih and Yen's scheme.     

Crucial problems on security assessment of a building site adjacent to an excavated high slope

The subject of this work is the assessment on the stability of an excavated high slope in order to insure the security of the building site adjacent to the slope,which is frequently encountered in town construction in mountainous areas due to terrain limit.On the base of some typical engineering cases in Chongqing,several crucial problems on security assessment of building site adjacent to an excavated high slope,including the natural geological conditions and man-destroyed degree,engineering environment,potential failure pattern of the high slope,calculation parameters and analysis methods,are roundly discussed.It is demonstrated that the conclusion of security assessment can be determined according to the aspects above-mentioned,and the security assessment is one of the fundamental data to insure the safety of the related construction,site and buildings.     

The Best Age For A Child To Begin

What is the best age for a child to begin learning a foreign language? It is commonly believed that children are supposed to form their learning skill gradually, according to the development of their age and language learning mechanism. But some hold the view that one of the keys to raising a linguistically proficient child is to have him study from as early an age as possible. In this way, one can make full use of a child's natural aptitude.     

Using the Wavelet as the Private Key for Encrypting the Watermark

Watermarking is an effective approach to the copyright protection of digital media such as audio,image,and video.By inspriation from cryptography and considering the immensity of the set of all possible wvaelets,it is presented that in wavelet domain watermarking,the associated wavelet can be considered as the private key for encrypting the wavtermark so as to enhance the security of the embedded mark.This idea is partly supported by the fact that from computational complexity viewpoint.It is very time-consuming to search over the immense set of all candidate wavelets for the right one if no a priori knowledge is known about it .To verify our proposal,the standard image“Lena”is first watermarked in a specific wavelet domain,the watermark recovery experiments are then conducted in the wavelet domain for a set of wavelets with the one used for mark embedded in it ,separately.It follows from the experimetal results that the mark can be recovered only in the right wavelet domain,which jusstifies the suggestion.     

Security and privacy threats in RFID traceability network

To address security and privacy issues in radio frequency identification (RFID) traceability networks, a multi-layer privacy and security framework is proposed, which includes four facets: a security model, a communication protocol, access permission and privacy preservation. According to the security requirements that are needed in an RFID system, a security model that incorporates security requirements that include privacy of tag data, privacy of ownership, and availability of tag identity is introduced. Using this model, a secure communication protocol that can be used for anti-counterfeiting, automatic identification and privacy preservation is then developed. In order to manage the number of parties, data records of items, and complicated transitions of access permissions in an item-level traceability context, a well-designed access control protocol is proposed to parties that can prove the physical possession of an item;meanwhile, to address the privacy issues during data sharing in an RFID network, a vision of database systems that take responsibility for the privacy of the data they manage is also presented.     

Student Choice in English Study

There are three student-centered approaches introduced in this essay. The first one focuses on the design of syllabuses that relate specifically to an analysis of students’needs. The second one is about the provision of classroom activities that encourage more student participation. Last one is concerned with allowing students a greater role in the management of their learning, by providing opportunities for student choice in the method and scope of study . These can contribute a lot to Chinese English class in the situation where many so-called students-centered approaches which mislead many teacher.     

Action Research on Using Self-and Peer-assessment in Teaching of English Writing

The main purpose of this paper is to explore the perception of applying self-and peer-assessment in English writing,through an Action research process.The learning in the programme,the students have learnt translating Chinese into written English for first stage,and have learnt writing in English for second and third stage through self-and peer-assessment.The research result shows that the most students feel that the process of self-and peer-assessment are useful for improving their English writing skill and they feel that self-reflection and peer discussion around their English writing is helpful for promoting the development of self-and peer-assessment.Especially,key findings about four types of students are more important.Overall,based on student’s perception about using self-and peer-assessment,learning written in English is also an ongoing research,it can develop the ability of students’ ability to solve problems independently,and raise their language communicative competence gradually.     

Integrating social responsibility into an entrepreneurship education program： A case study

Entrepreneurship education in the South Africa is often presented as a neutral discipline. Yet fundamental to any entrepreneurship education program should be the integration of key issues, such as ethics, values and social responsibility. This paper reports on a study that set out to explore student teachers experiences of engaging in an entrepreneurship education program specially enhanced to create an awareness of the link between entrepreneurship and social responsibility. It argues that exposure to a program of this nature is a powerful means to dispel the myth that entrepreneurship is a neutral discipline and that such exposure creates useful avenues for student teachers to examine their own constructions and perceptions of entrepreneurship and social responsibility. This paper draws on data constructed in a qualitative research project that engaged the tenets of symbolic interactionism in order to understand how students experienced the program and to understand their changing perceptions.     

Risk pre-warning of tender evaluation for civil projects:an outlier detection model

The marking scheme method removes the low scores of the contractor‘s attributes given by experts when the overall score is calculated, which may result in that a contractor with some latent risks will win the project. In order to remedy the above defect of the marking scheme method, an outlier detection model, which is one mission of knowledge discovery in data, is established on the basis of the sum of similar coefficients. Then, the model is applied to the historical score data of tender evaluation for ci...     

Deformation mechanism of high-stress and broken-expansion surrounding rock and supporting optimization based on the gray correlation theory

Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deformation and damage of roadway surrounding rock and an analysis of its mechanism were carried out. The gray correlation theory was used in support scheme optimization design. First, causes and mechanism of deformation of the 1 000 m horizontal transport channel were analyzed through field investigation, laboratory test and data processing methods. We arguued that poor engineering geological conditions and deep pressure increases were the main factors, and the deformation mechanism was mainly the ground deformation pressure. Second, the gray correlation theory was used to construct supporting optimization decision method in the deep roadway. This method more comprehensively considers various factors, including construction, costs, and supporting material functions. The combined support with pre-stressed anchor cables, shotcrete layer, bolt and metal net was put forward according to the actual roadway engineering characteristics. Finally, 4 support schemes were put forward for new roadways. The gray relational theory was applied to optimizing the supporting method, undertaking technical and economic comparison to obtain the correlation degree, and accordingly the schemes were evaluated. It was concluded as follows： the best was the flexible retaining scheme using the steel strand anchor; the second best was the one using plate anchors on the top and rigid common screw steel bolt on the two sides; the ttiird was; the rigid common screw steel bolt in full section of roadway; and the worst is the planished steel rigid support. The optimized scheme was applied to the 1000 m level of new excavation roadway. The results show that the roadway surrounding rock can reach a stable state after 5 to 6 months monitoring, with a convergence rate less than 1 mm/d.     

Values of Estonian students, teachers and parents

R. Inglehart （1990, 2005） considers values to be one＇s reactions to changes in the environment. According to his approach values develop in the socialisation process. Values can be divided into traditional, modernist and postmodernist. According to Rokeach （1973）, values are an element of culture, an image of the desirable that might not be directly expressed in human behaviour. Kalmus and Vihalemm （2004） found, based on Rokeach＇s and Schwartz＇s （1992） questionnaires, that Estonians consider most important values to be health, strong family ties, peace in the world, clean environment, happiness and state security. Also, the results of the study “infants＇ and toddlers＇ intelligence and the impact of the growth environment” financed by Estonian Science Foundation, allow to conclude that parents consider most important that children are healthy, happy and smart （Veisson, 2001）. In the framework of the state financed project of Tallinn University “school as developmental environment and students＇ coping” （2003-2007） questionnaires were administered to 3838 students, 2048 parents, 620 teachers and 120 school directors. According to the mean value a hierarchy of 14 values was formed. It appeared that students and parents think that the most important is academic success, whereas teachers place academic success on the 3rd-4th place and school directors even on the 8th place. Teachers and school directors consider the most important is their school students＇ security and the second is honesty. Also students and parents think that honesty is the 3rd most important value at school. Students consider politeness and parents discipline worth giving the second place among school values. Students＇ health is relatively highly valued by teachers and school directors （in case of both groups the 3rd place）. Unfortunately, children themselves and their parents think that in their school health is not very highly valued （10th place）. Joy of school came on the last place in the values hierarchy.     

Design of a long range nano-scale resolution mechanism

This paper presents the development of a coarse-fine dual precision positioning stage to achieve long travel range and high accuracy. The fine stage is arranged in series with a coarse stage. The key in the fine stage design is the choice of a toggle mechanism for a tight mechanical loop with high stiffness and compactness. We designed the toggle mechanism for reduction of the displacement to suppress signal noises, The performance of the coarse and fine stages was verified with an optical encoder and capacitive sensor, respectively. The measurement results show that the dual mechanism has a travel range of 1 mm and resolution of 30 nm.     

Pedagogical Content Knowledge of Inquiry： An Instrument to Assess It and Its Application to High School In-Service Science Teachers

It is argued that the lack of consensus on what constitutes an inquiry-based approach makes the generalization about it difficult, because the concept is relatively unspecific and vague. This problem can partially be solved by constructing a set of activities promoted by inquiry, thus defining the inquiry objectives for classroom and laboratory teaching. Five high school and college Mexican teachers＇ PICK （pedagogical inquiry/content knowledge） was documented and assessed by means of Loughran, Mulhall and Berry＇s （2004） l-CoRe （inquiry content representation） developed by the authors through a proposal of a set of seven inquiry activities. They were also interviewed to construct the professional and pedagogical experience repertoires, a second tool by Loughran et al. （2004） to document PICK. It was observed that all teachers interviewed have used inquiry to modify their students＇ way of thinking, mainly through question posing. Some of them employed research as their main tool to promote scientific inquiry but others mentioned the lack of time to do it. It is interesting to notice that in spite of the fact that inquiry is out of the curriculum in M6xico, the teachers make use of it to improve their teaching practice. According to their answers, their actions in the classroom or the lab were classified within the three general approaches expressed by Lederman （2004）： implicit, historical and explicit. It is concluded that a given teacher cannot be classified exclusively in one of them, because in his/her activities one general approach overlaps the others. The authors conclude that Lederman＇s classification has to be taken into account as an orientation to characterize a given activity of one teacher, even though the same teacher may use another activity characterized by other general approach. That is, Lederman＇s classification applies to characterize activities, not persons     

How the World Wide Web Started世界网（万维网）是怎样开始的

Tim Berners-Lee is the man who wrote the software (软件)programme that led to the foundation of the World Wide Web. Britain played an important part in developing the first generation of computers. The parents of Tim Berners-Lee both worked on one of the earliest commercial computers and talked about their work at home.