People Resourcing Essay Example | Topics and Well Written Essays - 2500 words

People Resourcing - Essay Example Different organisations have different ways of allocating jobs and responsibilities to their workers. In many instances, the manufacturing process of a company will be divided into separate tasks that can be carried out by a number of employees. Specialised job responsibilities will allow organisational managers to match employees with tasks that are based on their competencies. This allows for employees to be able to focus on their specific areas of expertise. For instance, a corporation ought to employ engineers to carry out any design responsibilities and business experts cater to promotional aspects instead of giving more responsibilities to the present workers who might have some small talent in any of these areas. The law of comparative advantage verifies that this specialisation will end up yielding a higher output than would be achieved if the company used the existing workers to carry out these extra tasks. With specialised job assignment, every worker is trained to finish j ust one basic function. This is much more cost effective than would be the case if all the workers were trained to be able to work efficiently in more than one task. For example, if a corporation has need of an engineer and a semi skilled worker for tasks at the production line, specialised, in contrast to broad task assignment gives the company the chance to employ one partially skilled worker and one engineer (Von Krogh, 2003). With broad task allocation, the education level needed is typically of the highest level. Therefore, it will be more expensive for the corporation to employ two employees with college degrees than just one. Specialised task assignment is more cost effective than broad task assignment. Specialised task assignments have just one impediment are. This is the fact that they do not retain the knowledge used in some of the creative processes included in the process of manufacturing a product. For instance, if a company’s engineers have to plan for and creat e a new copier but do not take part in the production and advertising functions, they will not have the necessary feedback to create successful merchandise. This feedback will be traduced in consumers’ needs and future market opportunities. In addition, if just one employee is responsible for the assemblage, it is a likely thing that a worker will conduct his or her job with less care than if there were other workers. Also, to cut coordination costs, the functions of specialised workers have to be corresponding. For example, a firm can establish the procedures as well as methods needed to process a definite number of products in a given period of time so that technicians can make use of the same procedures to make other products. This calls for good coordination to exist between various product units. An organisation’s managers also have to ensure that the workers remain focused on their specific functions instead of the overall function of ensuring that the goods they produce are sold. For instance, the performance of the production division of a company could be assessed on the basis of the number of manufactured units, while the marketing division’s performance might be based on the number of transactions made; but if the quality of the goods is compromised, the sales numbers will begin to decline even though the marketing division’s performance stays high. Workers are more likely to develop closer

Research Critiques Essay Example | Topics and Well Written Essays - 5000 words

Research Critiques - Essay Example Questions asked of the students determined their understandings of plagiarism, the hardships they had to undergo to avoid plagiarism, and how they have learned to write without plagiarizing.iv Phase two concerned the development of learning materials. The materials developed were evaluated with undergraduate psychology students, some of whom had participated in Phase one. Much like the focus groups in Phase one, the number of sessions was determined by the data.v The latter phase then incorporated the student feedback into the design of the learning materials. The research design included a number of processes whereby feedback was ascertained from students and teaching staff, to ensure the applicability and usefulness of the materials and their responsiveness to students' needs. The results of the study stated in Phase one represented the students' understandings of plagiarism particularly on defining plagiarism, difficulties in writing to avoid plagiarism, strategies to avoid plagiarism, and student suggestions for course improvement. The results in Phase two represented the development and evaluation of the learning materials. Based on the findings three tutorials and a 'tip sheet' were developed. The Tip sheet provided students with a practical guide on the definition of plagiarism and suggestions for its avoidance when writing [for this particular subject, psychology].vi Information is outlined on the following six areas: time management, note taking, critical reading, paraphrasing, referencing, and practice. The researchers finally proposed learning materials that sees a number of advantages over alternate methods of plagiarism reduction: 1) The inclusion of the materials into an introductory unit is preventive rather than reactive; 2) Providing all students with materials as a component of the course is a universal rather than selective approach; vii 3) The materials can be easily adapted to alternative teaching modes of delivery such as print based external and online modes; 4) The materials can be incorporated into units without changing the assessment, official unit outlines, and so on; 5) Although the materials were developed for psychology students, the materials could be adapted to meet the needs of students in other schools and departments; and 6) Once the materials have been implemented into the course, their advantages can be sustained without further staff time commitment. The researchers said the same cannot be said for the provision of additional tutorials, workshops, and programs outside of class time. Article 2 Storch, J. B;Storch, E. A; &Clark, P. (2002, Nov/Dec). Academic dishonesty and neutralization theory: A comparison of intercollegiate athletes and non-athletes. Journal of College Student Development. Retrieved February 9, 2006 from: http://www.looksmartgradschools.com/p/articles/mi_qa3752/is_200211/ai_n9165977#continue The purposes of this study were: (1) to examine the self-reported frequency of academic dishonesty in a sample of student

Visual Information Encryption by D-H Key Agreement

Visual Information Encryption by D-H Key Agreement Visual Information Encryption by D-H Key Agreement and Visual Cryptography Abstract Visual cryptography provides secured digital transmission which is used only for one time. In order to make visual cryptography reusable Diffie and Hellman (D-H) key is used. The original images can be reuse by using this scheme. It is effortless and uncomplicated technique to execute the secret image for shadow images. The shadow images are the shrunken version of the original image, in which the secret image share is embedded. These are used to guard the data and secret images in the internet so that it is not accessed by any unauthorized persons. Visual cryptography divides the image into secret shadow images. After this these shadow images are distributed in the original image. Recovering of secret image is done by human visual system by piling all the shadow images. As this Visual cryptography is used only once D-H key agreement was used to make it reusable by using D-H key scheme in it. Objectives: Provision of security for hidden images Reusing of the original image is possible by this technology Images should be visible only to human visual system Literature Review In this project a visual cryptography scheme is used for encrypting the information. Visual cryptography is an encryption method which is used to hide the information in an image, decrypted can be done by human visual system. By using only this scheme the reusing is not possible. The image which is recovered after decryption will not be same as original image so it cannot be reused. For the reuse of the visual cryptography Diffie and Hellman (D-H) key agreement method and Toral Automorphism (TA) can be used. In this both secret and symmetry-key representation can be used (Chao-Wen Chan and Yi-Da Wu, 2008). Visual cryptography is the scheme which facilities the secret sharing of the pictures or data. The pixels of the pictures or data that need to be transmitted secretly will be treated as an individual secret which can be shared using a secret sharing scheme. The picture is first split into two or more shared images the secret data are embedded. At the decryption side images are join ed on the transparent paper to get the secret picture or data. This is the way in which the first visual cryptography was started (Borivoje Furht, Edin Muharemagic and Daniel Socek, 2005). Using current methods the Visual cryptography scheme will allow the encoding of the secret image into shares; this is done in the form of transparencies. These shares are distributed to the participants, such that only the qualified subsets of participants can recover the secret image visually. This is done by superimposing the share images one over the other which are obtained from the original image (Carlo Blundo and Stelvio Cimato, 2005). In this scheme the devices are used for encoding of secret information and the decoding is done with human vision directly. For encoding, the visual cryptography will cryptographically encode the binary secret data into shares of the pattern which will be random. Then the shares are copied on to the transparencies with the same number of transparencies as shar es. The transparencies are distributed among the participants, one for each participant. The decoding of the data or picture is done only when all of the participants superimpose their transparencies (Alan Conrad Bovik, 2005). The importance of this scheme is that there is no need for data expansion. The resolution of the data will not be lost by using this scheme. By using this scheme the image will be secure against the most important cryptanalytic attacks. The computation complexity will be less since it involves only XOR operations. By using XOR operations the share images are combined to form the encrypted images. The authentication of the image will be based on the global visual effect, so local defects due to noise will not affect the final result. The most important aspect of this scheme is that the decoding of the secret data or image can be done with human vision without any decoding equipment (Kiyoharu Aizawa, Yuichi Nakamura and Shinichi Satoh, 2004). The previous techno logies that came into existing before visual cryptography are two-out-of two visual threshold schemes, two-out-of-n visual-threshold scheme. In a two-out-of two visual threshold scheme the secret can be any type of data (Abhishek Parakh and Subhash Kak, 2006, p.1). For an image comprising of white and black pixels, this image can be encoded as a binary string. In this scheme the 0 will represent a white pixel and 1 represents a black pixel and the result will be sent in two shares. The security problem by this is having only 50 percent of resolution will be obtained because the image is divided into only two shares and if the new shares of data are found the image can be decrypted very easily. A two-out-of-n visual-threshold scheme is more secure when compared with the first. In this scheme also the pixels are divided into two, but the shares will be n. By this the security will increase. When compared with the D-H key agreement the resolution of these schemes will be less and secur ity will also be less (Doug Stinson, 1999). The D-H key agreement is used to make possible the reuse of visual cryptography. The Diffie-Hellman key agreement used an interface known as D-H key interface. This interface is used for password based Encryption. These interfaces typically can be used by the programmer who is implementing a Cryptographic provider or who wants to implement a cryptography algorithm (David Flanagan, 2005). Diffie- Hellman Key agreement is also known as exponential key exchange. This key provides the solution to the key distribution problems, allowing two parties, never having met in advance to share key material for establishing a shared secret by exchanging messages over an open channel. This is a fundamental technique providing unauthenticated key agreement. The main goal of an authenticated Key establishment protocol is to distribute key of data. The established key should have precisely the same attributes as a key established face to face, it should be distributed uniformly at random from the key space, and an unauthorized entity will not be able to learn anything about the key (Alfred J.Menezes, Paul C. Van Oorschot, and Scott A. Vanstone, 1997). D-H key agreement protocols involve the derivation of the shared secret information based on compatible D-H keys between the sender and recipient. The information is then converted into the cryptographic keying material for other algorithms. A variation of the Diffie-Hellman is used for converting the shared secret data into an arbitrary amount of keying materials (Manuel Mogollon, 2008). According to Michael Baake and John A G Roberts (2001, p.1) Toral Automorphisms will be represented by the uni-modular integer matrices, are investigated with the help of symmetries and also reversing symmetries group of matrices with a simple spectrum through their connection with unit groups in orders of algebraic number fields. The reversibility will derive the necessary conditions in terms of the distinctive polynomial and the polynomial invar iants. This shows that the Voiculescu- Brown entropy of the non-commutative toral automorphism arising from a matrix S in is at least half the value of the topological entropy of the corresponding classical toral automorphism. This is a new method used to prove the position limit laws in the theory of dynamical systems, which is based on the Chen-Stein method combined with the analysis of the homo clinic Laplace operator and some other homo clinic considerations (Massimo Franceschetti and Ronald Meester, 2002, p.2). The main use of this is to generate a disorder in the arrangement of digital images. The equation (1) define the two dimensional matrix. The new technology that can be used for the visual cryptography is adaptive order dithering technique. By using this technique the decrypted image size can be reduced and also the quality of decryption image can be improved. In this technique the technique will get adaptive to the data that is used (Nagaraj V. Dharwadkar, B.B. Amberker and Sushil Raj Joshi, 2009). From the above context it can be understood that visual cryptography is a scheme in which the secret data can be transmitted without getting decoded by others. Chapter 1: Introduction 1.1. Overview Visual Information system significantly enlarges the applications scope of information systems and typically deals with the general purpose multimedia operating system that is supported by multimedia hardware and high bandwidth network. Visual information system involves variety of facilities for efficient visual information presentation and visualization. This system actually provides inter related visual and multimedia information to support the operations, management and decision making functions in an organization. These are text oriented which provides reports, decision-making information and documents for all levels of hierarchy in the organization. With the increase in multimedia platforms, visual information has become more available (Clement H. C. Leung, 1997). In recent years, there has been a rapid growth of information technology for human to communication on the Internet. Since Internet is public, with the advancement of information technology, communication through inte rnet has increased rapidly. As internet can be accessed by everyone and anyone can easily access the information and transmit it without any protection there is possibility of grabbing the information as it became secondary data. So in order to avoid hacking of sensitive information, it should be encrypted before transmission. In order to protect the information Diffie and Helman (D-H) proposed a key agreement scheme that is implemented when two parties agree on a common session key. This key agreement also helps in improving the reusable process. This method is used to compute a common image for encryption and decryption with two parties (Chao-Wen Chan and Yi-Da Wu, 2008). The D-H algorithm does not encrypt data or make a digital signature. This is exclusively used for the generation of shred secrets. The DH key agreement can be split into three parts; they are parameter generation that generates non secret public value and is expensive process, next is phase1generatres two key exc hange values for the parties and phase2 is the originator and recipient that computes the functions in the given image (Blake Dournaee, 2002). DH key agreement has a nice property that it is not sensitive to off-line attacks but it is sensitive to man-in-the-middle attacks (Christian Gehmann, Joakim Persson and Ben Smeets, 2004). In Diffie and Hellman (D-H) key agreement method both the secret and symmetry key are represented in binary image. It is simple and easy to be implemented especially for shadow images. Thus, it can be applied in many electronic business applications. There after Naor and Shamir proposed a methodology named visual secret sharing that provides secrecy to the information and avoids illegal activities; this process is called as Visual Cryptography. This process provides secrecy by partitioning the secret digital image into several shadow images that are recovered by the human visual system by piling all those images together (Jeng-Shyang Pan, Hsiang-Cheh Huang and L. C. Jain, 2004). Hence it can be stated that in order to safeguard the images visual cryptography and DH key agreement are used where the images are split into shadow images and sent which then will be combines and viewed by the human visual system. It is secured by encryption and decryption of images with a key to be presented. Visual cryptography is seen as a one time pad system that cannot be reused, in further sections of the study the implementation of Diffie and Hellman (D-H) key agreement method is researched in detail so that visual cryptography can be reused. 1.2. Aims and Objectives Aim: To research on visual information encryption by D-H Key agreement and visual Cryptography Objectives: Provision of security for hidden images Reusing of the technology again and again Images should be visible only to human visual system 1.3. Purpose of Study The main purpose of studying the Visual Encryption is to provide a unified overview of techniques for the encryption of the image and video data, ranging from commercial applications like DVD or DVB to more research oriented topic and recently published material. To serve this purpose of Visual Encryption has the different techniques of a unified viewpoint, it provide an extensive use of Visual Encryption. Digital visual data is usually organized in a rectangular arrays denoted as frames, the elements of these array are denoted as pixels. Each pixel is a numerical value specifies the intensity of the pixels (Andreas Uhl and Andreas Pommer, 2005). In the latest year, there has been a rapid growth of the information technology for the human to communication on the Internet. As Internet has become the open public, anyone can easily read information and perform the successful transmission of the information without protection. In order to provide the proper security to the information, V isual Information Encryption by D-H Key study is necessary (chao-Wen and Yi-Da Wu, 2008). Visual Information Encryption provides the secure connection and protects data from unexpected modification by hackers or other outsiders. In D-H key encryption a common password is required for all the attendees to participate in the same conference, which gives more security to the information (Encryption, 2008). Visual information Encryption provides the Encryption formats as a standard function. Thus, the main purpose of the study is to implement a visual secret sharing scheme through visual cryptography in order to avoid sensitive information being illegally read or modified because the observations made from the recent electronic business applications on the Internet reveal that the amount of data exchanged is small and the exchanged data requires secrecy. 1.4. Research Context With the rapid increase in visual information, the digital and video encryption approaches are widely studied upon various resources like visual net meetings. This application mostly requires ultra high security to keep the images and video dat confidential among users; nobody can retrieve the content without a key for decryption. Thus, from this point of view image encryption is considered as a basis for visual encryption. Visual Cryptography is a topic that finds its way into every nook and cranny of the networking world. Everyone has their own ideas of how it should work and their own understanding of how it does work. The problem with the encryption is that there are several different types, and these type works in several different ways. And most companies want encryption, they dont necessarily know what type of encryption they want, and what the difference are between the types. Here this is designed to give a good overview of the current encryption technology (Eric Quinn, 2009 ). The visual cryptography is mainly used in maintaining images secretly for not to be accessed by the unauthorized persons. By using this technology the images can be visual by the user but it cannot be accessed by unauthorized persons. As there is increasing growth in the computer networks and in distributed a computing application visual cryptography plays an important role in providing security (visual cryptography, 2009). In binary images scheme the visual cryptography helps in maintaining the secrecy for not providing authorization to intruders. The visual cryptography provides an infinite computation power that messages cannot be identified. This visual cryptography is in identification of bank customers, verification of electronic voting and anti spam bot measures for maintaining the secrecy to avoid intruders Visual cryptography provides a way for secretly maintaining the information and data. Visual cryptography is used in many applications for maintaining data secretly fo r not be authorized by the intruders (Nagaraj V. Dharwadhakar, Amberker and susil Raj Joshi, 2009). This system actually supplies inter related visual and multimedia information to support the operations, management and decision making functions in an organization. This process provides confidentiality by dividing the secret digital image into several images that are healthier by the human visual system by those images together. Visual cryptography strategy is suggested to combine the key agreement scheme with a shadow image without building a secure connection. Thus, visual cryptology uses public key algorithm for having maintain secretly (Kiyoharu Aizawa, Yuichi nakamura and shinichi satoh, 2004). Many organizations are using this methodology for not having interruptions in data. Visual cryptography uses different encryption and decryption techniques and many authentications for not be accessed by unauthorized persons and maintains secrecy. In this research D-H key algorithm is us ed for having secrecy and privacy can be maintained. By implementation of new encryption schemes provides secrecy in an effective manner. 1.5. Research Method Qualitative approach is appropriate for this research method. Qualitative Research Practice starts with the premise that one can improve their research skills by seeing what researchers actually do in particular projects and by adding their actions and plans into their own research practice. It actually demonstrates the benefits of using practical methods from real-life knowledge and will be necessary reading for anyone interested in the process of doing social research (Clive Seale, 2004). It is a field of inquiry that explains discipline and subject matters. It is called as ethnographic research. It involves collection of narrative data in a natural setting in order to gain insights into phenomenon of interest. This research studies many variables over an extensive period of time to find out the way things are, how and why they came to be that way and what it all means. Qualitative researchers do not want to interfere or control anything. The most common method of data collection i nvolves participant observation (Michael Huberman Matthew and Miles, 2002). Qualitative analysis offers a cluster of very useful procedures like guidelines, techniques etc. It actually refers to the educational issues and the understanding of learning and cognition (Pamela S. Maykut and Richard Morehouse, 1994). Hence, it can be said that the secondary data is preferred for this research while searching the related information to it as the other approaches cannot provide a better data to the research. Chapter 2: Literature Review 2.1. Overview Visual Cryptography is a particular encryption method used to hide information in images in such a way that it can be decrypted by the human visual system if the correct key image is applied. This method was suggested by Naor and Shamir in 1994. Visual Cryptography applies two transparent images. One image consist random pixels and the other image consist of the secret information. In visual cryptography it is not possible to recollect the secret information from one of the images. Both transparent images and layers are involved to reveal the information (Kiyoharu Aizawa, yuichi Nakamura and shichi satoh, 2004). The simplest method to implement Visual Cryptography is to bring out the two layers against a transparent sheet. When the random image contains genuinely random pixels then it can be seen as a onetime pad system and will offer infrangibly encryption. In visual cryptography pixel is divided into white and black blocks. In this chapter, importance of visual cryptography is disc ussed and a New Visual information Encryption Scheme is proposed followed by the explanation of Security analysis on images with the previous technologies. 2.2. Visual Cryptography Visual Cryptography refers to a secret sharing method that will encrypt the secret message into a number of shares and does not require any computer or calculations for decrypting the secret image rather the secret message will be reconstructed visually by overlaying the encrypted shares the secret image will become clearly visible. Visual cryptography scheme on a set P of n participants can be defined as a method of encoding the secret image into n shares so that the original image will be obtained by stacking specific combination of shares onto each other. Visual cryptography technique was initiated by the Naor and Shamiri at Eurocrypt 94. It is a process used for separating one image into various shares. Visual cryptography solutions functions on binary inputs. Visual cryptography is a special technique used to hide information in images in such a way that it can be decrypted by the human vision when the correct image is used. It uses two images one image contains secret informati on, in visual cryptography it is not possible to retrieve the secret information from one of the images, both transparent images are required to reveal the information. To print two layers into the transparent sheet is the simplest way to implement Visual cryptography (jeng shying pan, Hsiang cheh Huang and L. C. Jain, 2004). If the random image contains random pixel then it can be seen as a onetime pad system and will offer unbreakable encryption. These two layers slide over each other until they are correctly aligned where the hidden information appears. This type of visual cryptography which restores the image by stacking some significant images together is known as extended visual cryptography. Generally, visual cryptography suffers from the deterioration of image quality. The basic two cryptography models consists of a secret message encoded into two transparencies, one transparency representing the cipher text and the other acting as a secret key. Both transparencies appear to random dots when inspected individually and does not provide any information about the original clear text. By carefully aligning the transparencies the original message is reproduced (Borivoje Furht, Edin Muharemagic and Daniel socek, 2005). The original decoding is accomplished by the human visual system. Visual cryptography scheme is a visual secret sharing problem in which the secret message is viewed only in black and white pixels. Each pixel in the original image is represented by at least one sub pixel in each of the n transparencies or shares generated. Each share is comprised of collection of m black and white sub pixels where each collection represents a particular original pixel. The contrast of Visual Cryptography Scheme is the difference between the minimum number of black sub pixels in a reconstructed (secret) black pixel and the maximum number of black sub pixels in a reconstructed (secret) white pixel (Kiyoharu Aizawa, Yuchi Nakamura and Shinichi Satoh, 2004). The m ain instantiation of visual cryptographic realizes a cryptographic protocol called secret sharing. The important thing in secret sharing is it relies on a human visual system to perform the decryption. In a conventional secret sharing a secret shared among n participants can pull their shares and recover the secret but the subsets of the forbidden can obtain no information about that. Visual secret sharing schemes inherits all applications of conventional secret sharing schemes most notably access control. An example of the encoding of white and black pixels in a 2 out of 2 scheme can be seen in Figure 1. Here two shares out of the two generated would be needed to recover the original image. Since only two shares are generated, n = 2. White box represents a single white or black pixel in the original image. Sub pixel assignments that would be given to shares #1 and #2 respectively. The number of sub pixels per share used to represent the original pixel is four Finally, the overall visual effect when shares #1 and #2 are correctly aligned on top of one another. Notice that when the shares in this example are combined the original black pixel is viewed as black; however, the original white pixel takes on a grey scale. The structure obtained from either white or black pixel representation can be described by an n. Similar to the area of the secret sharing, more generally structures have been studied in the visual cryptography. The basic model of the visual cryptography consists of a sever al umber of transparency sheets. On each transparency a cipher text is printed which is identical from random noise. The hidden message is reconstructed by stacking a certain number of the transparencies and viewing them. The system can be used by anyone without any knowledge of cryptography and without performing any cryptographic computations. Naor and Shamir have developed the Visual Secret Sharing Scheme (VSSS) to implement this model [Naor95] (Mizuho Nakajima and Yasushi Yamaguchi, 2002). Thus, from the above discursion it can be stated that Visual cryptography is a special technique used to hide information in images in such a way that it can be decrypted by the human vision when the correct image is used. It is a simple and clear scheme that can partition the secret image into a number of shadow images and the dealers can distribute these shadow images to participants. The Visual cryptography scheme makes use of human visual system for recovering secret images by staking vari ous shadow images. 2.3. Importance of Visual Cryptography Visual Information system importantly elaborates the diligences scope of information systems and deals with the multimedia operating system which is supported by multimedia hardware and high bandwidth network. These are text oriented which provides reports, decision-making information and documents for all levels of hierarchy in the organization (Carlo Blundo and Stelvio, 2005). With the increase in multimedia platforms, visual information has become more available with the advancement of information technology; contact through internet has increased rapidly. Visual information system requires many kinds of facilities for effective visual information presentation and visualization. This system actually supplies inter related visual and multimedia information to support the operations, management and decision making functions in an organization. As internet can be accessed by everyone and anyone can easily access the information and transmit it without any protection there is possibil ity of grabbing the information as it became secondary data. So in order to avoid hacking of sensitive information, it should be encrypted before transmission (Yongfei Han, 1997). In order to protect the information Diffie and Helman (D-H) proposed a key agreement scheme that is implemented when two parties agree on a common session key. This key agreement also helps in improving the reusable process. This technique is utilized to calculate a common image for encryption and decryption with two parties. The D-H algorithm does not encrypt data or make a digital signature. This is exclusively used for the generation of shred secrets. The DH key agreement can be split into three parts; they are parameter generation that generates non secret public value and is expensive process, next is phase1generatres two key exchange values for the parties and phase2 is the originator and recipient that computes the functions in the given image. DH key agreement has a nice property that it is not sen sitive to off-line attacks but it is sensitive to man-in-the-middle attacks. There after Naor and Shamir proposed a methodology named visual secret sharing that provides secrecy to the information and avoids illegal activities (Jeng-Shyang Pan, Hsiang-Cheh Huang and L. C. Jain, 2004). This process is called as Visual Cryptography. This process provides secrecy by partitioning the secret digital image into several shadow images that are recovered by the human visual system by piling all those images together. It is secured technique where the data cannot be traced by others. In classic secret sharing, algorithms for splitting and sharing secret information are a stem of cryptography. In the most general case, their objective is to generate such parts for the data and that could be shared by multiple authorized persons. This problem of splitting information in a manner allowing its reconstruction by a certain n-person group interested in the reconstruction of the split information. Al gorithm solutions developed to achieve this objective and at the same time none of the groups of participants in such a protocol, whose number is lesser than the required m persons. It leads to opposing to read the split message. The algorithms for dividing information make it possible to split it into chunks known as shadows that are later distributed among the participants of the protocol. So that the shares of certain subsets of users collective together and these are capable of reconstructing the original information. There are two groups of algorithms for dividing information, namely, secret splitting and secret sharing. In the first technique, information is distributed among the participants of the protocol, and all the participants are required to put together their parts to have it reconstructed. A more universal method of splitting information is the latter method, i.e. secret sharing (Marek R. Ogiela and Urszula Ogiela, 2009). Thus, from the above discursion it can be sta ted that visual cryptography plays a vital role in securing the data and also in sharing the secret message as the data transferred through internet has been increased. rapidly. Advantages of visual cryptography Visual cryptography is simple to be implemented. Encryption incase of visual cryptography does not require any hard problem dependency. Specifically decryption algorithms are not required because a person aware of cryptography can easily decrypt the message. Cipher text can be Fax or e-mail in case of visual cryptography 2.4. Security analysis on images with the previous technologies The security analysis is the major aspect of the encryption. Analysis to the field of security will encounter the serious obstacle that deal is by nature not an exact science. The previous technologies which where there before the D-H key agreement encryption are manual encryption, transparent encryption, symmetric encryption and asymmetric encryption (Fedora Documentation Project, 2009). Visual cryptography can be seen as a one-time pad system. Then, it cannot be reused. Diffie and Hellman (D-H) key agreement method and Toral Automorphism (TA) such that visual cryptography can be reused. Both secret and symmetry-key are represented in binary image. The proposed scheme is simple and easy to be implemented for shadow images. Therefore, it can be used in many electronic business applications (Chao-Wen Chan and Yi-Da Wu, 2008). The Manual Encryption is a technique that will involve the use of encryption software. In this computer programs are used for encrypt various bits of information digitally. In this technique the encryption key is provided later in the process. The main security issues are the potential leakage through security insensible program and also the bad implementation may lead to re-encrypt with same key for same password (Bruice Schneier, 2007). Transparent Encryption is another type of computer software encryption. In this technique the data can be downloaded onto a computer to encrypt automatically. Every executable application and file created in the computer has an encrypted copy that can withstand power surges and protects information in case a computer is stolen. The security issues is the data which is automatically encrypted can be taken if the key provided is known (Cetin K. Koc, David Naccache and Christof Paar, 2001). The Symmetric Encryption is in which a letter or number coincides with another letter or number in the encryption code. This technique is commonly referred to as secret-key encryption. In this only single key is used for e ncrypting an Visual Information Encryption by D-H Key Agreement Visual Information Encryption by D-H Key Agreement Visual Information Encryption by D-H Key Agreement and Visual Cryptography Abstract Visual cryptography provides secured digital transmission which is used only for one time. In order to make visual cryptography reusable Diffie and Hellman (D-H) key is used. The original images can be reuse by using this scheme. It is effortless and uncomplicated technique to execute the secret image for shadow images. The shadow images are the shrunken version of the original image, in which the secret image share is embedded. These are used to guard the data and secret images in the internet so that it is not accessed by any unauthorized persons. Visual cryptography divides the image into secret shadow images. After this these shadow images are distributed in the original image. Recovering of secret image is done by human visual system by piling all the shadow images. As this Visual cryptography is used only once D-H key agreement was used to make it reusable by using D-H key scheme in it. Objectives: Provision of security for hidden images Reusing of the original image is possible by this technology Images should be visible only to human visual system Literature Review In this project a visual cryptography scheme is used for encrypting the information. Visual cryptography is an encryption method which is used to hide the information in an image, decrypted can be done by human visual system. By using only this scheme the reusing is not possible. The image which is recovered after decryption will not be same as original image so it cannot be reused. For the reuse of the visual cryptography Diffie and Hellman (D-H) key agreement method and Toral Automorphism (TA) can be used. In this both secret and symmetry-key representation can be used (Chao-Wen Chan and Yi-Da Wu, 2008). Visual cryptography is the scheme which facilities the secret sharing of the pictures or data. The pixels of the pictures or data that need to be transmitted secretly will be treated as an individual secret which can be shared using a secret sharing scheme. The picture is first split into two or more shared images the secret data are embedded. At the decryption side images are join ed on the transparent paper to get the secret picture or data. This is the way in which the first visual cryptography was started (Borivoje Furht, Edin Muharemagic and Daniel Socek, 2005). Using current methods the Visual cryptography scheme will allow the encoding of the secret image into shares; this is done in the form of transparencies. These shares are distributed to the participants, such that only the qualified subsets of participants can recover the secret image visually. This is done by superimposing the share images one over the other which are obtained from the original image (Carlo Blundo and Stelvio Cimato, 2005). In this scheme the devices are used for encoding of secret information and the decoding is done with human vision directly. For encoding, the visual cryptography will cryptographically encode the binary secret data into shares of the pattern which will be random. Then the shares are copied on to the transparencies with the same number of transparencies as shar es. The transparencies are distributed among the participants, one for each participant. The decoding of the data or picture is done only when all of the participants superimpose their transparencies (Alan Conrad Bovik, 2005). The importance of this scheme is that there is no need for data expansion. The resolution of the data will not be lost by using this scheme. By using this scheme the image will be secure against the most important cryptanalytic attacks. The computation complexity will be less since it involves only XOR operations. By using XOR operations the share images are combined to form the encrypted images. The authentication of the image will be based on the global visual effect, so local defects due to noise will not affect the final result. The most important aspect of this scheme is that the decoding of the secret data or image can be done with human vision without any decoding equipment (Kiyoharu Aizawa, Yuichi Nakamura and Shinichi Satoh, 2004). The previous techno logies that came into existing before visual cryptography are two-out-of two visual threshold schemes, two-out-of-n visual-threshold scheme. In a two-out-of two visual threshold scheme the secret can be any type of data (Abhishek Parakh and Subhash Kak, 2006, p.1). For an image comprising of white and black pixels, this image can be encoded as a binary string. In this scheme the 0 will represent a white pixel and 1 represents a black pixel and the result will be sent in two shares. The security problem by this is having only 50 percent of resolution will be obtained because the image is divided into only two shares and if the new shares of data are found the image can be decrypted very easily. A two-out-of-n visual-threshold scheme is more secure when compared with the first. In this scheme also the pixels are divided into two, but the shares will be n. By this the security will increase. When compared with the D-H key agreement the resolution of these schemes will be less and secur ity will also be less (Doug Stinson, 1999). The D-H key agreement is used to make possible the reuse of visual cryptography. The Diffie-Hellman key agreement used an interface known as D-H key interface. This interface is used for password based Encryption. These interfaces typically can be used by the programmer who is implementing a Cryptographic provider or who wants to implement a cryptography algorithm (David Flanagan, 2005). Diffie- Hellman Key agreement is also known as exponential key exchange. This key provides the solution to the key distribution problems, allowing two parties, never having met in advance to share key material for establishing a shared secret by exchanging messages over an open channel. This is a fundamental technique providing unauthenticated key agreement. The main goal of an authenticated Key establishment protocol is to distribute key of data. The established key should have precisely the same attributes as a key established face to face, it should be distributed uniformly at random from the key space, and an unauthorized entity will not be able to learn anything about the key (Alfred J.Menezes, Paul C. Van Oorschot, and Scott A. Vanstone, 1997). D-H key agreement protocols involve the derivation of the shared secret information based on compatible D-H keys between the sender and recipient. The information is then converted into the cryptographic keying material for other algorithms. A variation of the Diffie-Hellman is used for converting the shared secret data into an arbitrary amount of keying materials (Manuel Mogollon, 2008). According to Michael Baake and John A G Roberts (2001, p.1) Toral Automorphisms will be represented by the uni-modular integer matrices, are investigated with the help of symmetries and also reversing symmetries group of matrices with a simple spectrum through their connection with unit groups in orders of algebraic number fields. The reversibility will derive the necessary conditions in terms of the distinctive polynomial and the polynomial invar iants. This shows that the Voiculescu- Brown entropy of the non-commutative toral automorphism arising from a matrix S in is at least half the value of the topological entropy of the corresponding classical toral automorphism. This is a new method used to prove the position limit laws in the theory of dynamical systems, which is based on the Chen-Stein method combined with the analysis of the homo clinic Laplace operator and some other homo clinic considerations (Massimo Franceschetti and Ronald Meester, 2002, p.2). The main use of this is to generate a disorder in the arrangement of digital images. The equation (1) define the two dimensional matrix. The new technology that can be used for the visual cryptography is adaptive order dithering technique. By using this technique the decrypted image size can be reduced and also the quality of decryption image can be improved. In this technique the technique will get adaptive to the data that is used (Nagaraj V. Dharwadkar, B.B. Amberker and Sushil Raj Joshi, 2009). From the above context it can be understood that visual cryptography is a scheme in which the secret data can be transmitted without getting decoded by others. Chapter 1: Introduction 1.1. Overview Visual Information system significantly enlarges the applications scope of information systems and typically deals with the general purpose multimedia operating system that is supported by multimedia hardware and high bandwidth network. Visual information system involves variety of facilities for efficient visual information presentation and visualization. This system actually provides inter related visual and multimedia information to support the operations, management and decision making functions in an organization. These are text oriented which provides reports, decision-making information and documents for all levels of hierarchy in the organization. With the increase in multimedia platforms, visual information has become more available (Clement H. C. Leung, 1997). In recent years, there has been a rapid growth of information technology for human to communication on the Internet. Since Internet is public, with the advancement of information technology, communication through inte rnet has increased rapidly. As internet can be accessed by everyone and anyone can easily access the information and transmit it without any protection there is possibility of grabbing the information as it became secondary data. So in order to avoid hacking of sensitive information, it should be encrypted before transmission. In order to protect the information Diffie and Helman (D-H) proposed a key agreement scheme that is implemented when two parties agree on a common session key. This key agreement also helps in improving the reusable process. This method is used to compute a common image for encryption and decryption with two parties (Chao-Wen Chan and Yi-Da Wu, 2008). The D-H algorithm does not encrypt data or make a digital signature. This is exclusively used for the generation of shred secrets. The DH key agreement can be split into three parts; they are parameter generation that generates non secret public value and is expensive process, next is phase1generatres two key exc hange values for the parties and phase2 is the originator and recipient that computes the functions in the given image (Blake Dournaee, 2002). DH key agreement has a nice property that it is not sensitive to off-line attacks but it is sensitive to man-in-the-middle attacks (Christian Gehmann, Joakim Persson and Ben Smeets, 2004). In Diffie and Hellman (D-H) key agreement method both the secret and symmetry key are represented in binary image. It is simple and easy to be implemented especially for shadow images. Thus, it can be applied in many electronic business applications. There after Naor and Shamir proposed a methodology named visual secret sharing that provides secrecy to the information and avoids illegal activities; this process is called as Visual Cryptography. This process provides secrecy by partitioning the secret digital image into several shadow images that are recovered by the human visual system by piling all those images together (Jeng-Shyang Pan, Hsiang-Cheh Huang and L. C. Jain, 2004). Hence it can be stated that in order to safeguard the images visual cryptography and DH key agreement are used where the images are split into shadow images and sent which then will be combines and viewed by the human visual system. It is secured by encryption and decryption of images with a key to be presented. Visual cryptography is seen as a one time pad system that cannot be reused, in further sections of the study the implementation of Diffie and Hellman (D-H) key agreement method is researched in detail so that visual cryptography can be reused. 1.2. Aims and Objectives Aim: To research on visual information encryption by D-H Key agreement and visual Cryptography Objectives: Provision of security for hidden images Reusing of the technology again and again Images should be visible only to human visual system 1.3. Purpose of Study The main purpose of studying the Visual Encryption is to provide a unified overview of techniques for the encryption of the image and video data, ranging from commercial applications like DVD or DVB to more research oriented topic and recently published material. To serve this purpose of Visual Encryption has the different techniques of a unified viewpoint, it provide an extensive use of Visual Encryption. Digital visual data is usually organized in a rectangular arrays denoted as frames, the elements of these array are denoted as pixels. Each pixel is a numerical value specifies the intensity of the pixels (Andreas Uhl and Andreas Pommer, 2005). In the latest year, there has been a rapid growth of the information technology for the human to communication on the Internet. As Internet has become the open public, anyone can easily read information and perform the successful transmission of the information without protection. In order to provide the proper security to the information, V isual Information Encryption by D-H Key study is necessary (chao-Wen and Yi-Da Wu, 2008). Visual Information Encryption provides the secure connection and protects data from unexpected modification by hackers or other outsiders. In D-H key encryption a common password is required for all the attendees to participate in the same conference, which gives more security to the information (Encryption, 2008). Visual information Encryption provides the Encryption formats as a standard function. Thus, the main purpose of the study is to implement a visual secret sharing scheme through visual cryptography in order to avoid sensitive information being illegally read or modified because the observations made from the recent electronic business applications on the Internet reveal that the amount of data exchanged is small and the exchanged data requires secrecy. 1.4. Research Context With the rapid increase in visual information, the digital and video encryption approaches are widely studied upon various resources like visual net meetings. This application mostly requires ultra high security to keep the images and video dat confidential among users; nobody can retrieve the content without a key for decryption. Thus, from this point of view image encryption is considered as a basis for visual encryption. Visual Cryptography is a topic that finds its way into every nook and cranny of the networking world. Everyone has their own ideas of how it should work and their own understanding of how it does work. The problem with the encryption is that there are several different types, and these type works in several different ways. And most companies want encryption, they dont necessarily know what type of encryption they want, and what the difference are between the types. Here this is designed to give a good overview of the current encryption technology (Eric Quinn, 2009 ). The visual cryptography is mainly used in maintaining images secretly for not to be accessed by the unauthorized persons. By using this technology the images can be visual by the user but it cannot be accessed by unauthorized persons. As there is increasing growth in the computer networks and in distributed a computing application visual cryptography plays an important role in providing security (visual cryptography, 2009). In binary images scheme the visual cryptography helps in maintaining the secrecy for not providing authorization to intruders. The visual cryptography provides an infinite computation power that messages cannot be identified. This visual cryptography is in identification of bank customers, verification of electronic voting and anti spam bot measures for maintaining the secrecy to avoid intruders Visual cryptography provides a way for secretly maintaining the information and data. Visual cryptography is used in many applications for maintaining data secretly fo r not be authorized by the intruders (Nagaraj V. Dharwadhakar, Amberker and susil Raj Joshi, 2009). This system actually supplies inter related visual and multimedia information to support the operations, management and decision making functions in an organization. This process provides confidentiality by dividing the secret digital image into several images that are healthier by the human visual system by those images together. Visual cryptography strategy is suggested to combine the key agreement scheme with a shadow image without building a secure connection. Thus, visual cryptology uses public key algorithm for having maintain secretly (Kiyoharu Aizawa, Yuichi nakamura and shinichi satoh, 2004). Many organizations are using this methodology for not having interruptions in data. Visual cryptography uses different encryption and decryption techniques and many authentications for not be accessed by unauthorized persons and maintains secrecy. In this research D-H key algorithm is us ed for having secrecy and privacy can be maintained. By implementation of new encryption schemes provides secrecy in an effective manner. 1.5. Research Method Qualitative approach is appropriate for this research method. Qualitative Research Practice starts with the premise that one can improve their research skills by seeing what researchers actually do in particular projects and by adding their actions and plans into their own research practice. It actually demonstrates the benefits of using practical methods from real-life knowledge and will be necessary reading for anyone interested in the process of doing social research (Clive Seale, 2004). It is a field of inquiry that explains discipline and subject matters. It is called as ethnographic research. It involves collection of narrative data in a natural setting in order to gain insights into phenomenon of interest. This research studies many variables over an extensive period of time to find out the way things are, how and why they came to be that way and what it all means. Qualitative researchers do not want to interfere or control anything. The most common method of data collection i nvolves participant observation (Michael Huberman Matthew and Miles, 2002). Qualitative analysis offers a cluster of very useful procedures like guidelines, techniques etc. It actually refers to the educational issues and the understanding of learning and cognition (Pamela S. Maykut and Richard Morehouse, 1994). Hence, it can be said that the secondary data is preferred for this research while searching the related information to it as the other approaches cannot provide a better data to the research. Chapter 2: Literature Review 2.1. Overview Visual Cryptography is a particular encryption method used to hide information in images in such a way that it can be decrypted by the human visual system if the correct key image is applied. This method was suggested by Naor and Shamir in 1994. Visual Cryptography applies two transparent images. One image consist random pixels and the other image consist of the secret information. In visual cryptography it is not possible to recollect the secret information from one of the images. Both transparent images and layers are involved to reveal the information (Kiyoharu Aizawa, yuichi Nakamura and shichi satoh, 2004). The simplest method to implement Visual Cryptography is to bring out the two layers against a transparent sheet. When the random image contains genuinely random pixels then it can be seen as a onetime pad system and will offer infrangibly encryption. In visual cryptography pixel is divided into white and black blocks. In this chapter, importance of visual cryptography is disc ussed and a New Visual information Encryption Scheme is proposed followed by the explanation of Security analysis on images with the previous technologies. 2.2. Visual Cryptography Visual Cryptography refers to a secret sharing method that will encrypt the secret message into a number of shares and does not require any computer or calculations for decrypting the secret image rather the secret message will be reconstructed visually by overlaying the encrypted shares the secret image will become clearly visible. Visual cryptography scheme on a set P of n participants can be defined as a method of encoding the secret image into n shares so that the original image will be obtained by stacking specific combination of shares onto each other. Visual cryptography technique was initiated by the Naor and Shamiri at Eurocrypt 94. It is a process used for separating one image into various shares. Visual cryptography solutions functions on binary inputs. Visual cryptography is a special technique used to hide information in images in such a way that it can be decrypted by the human vision when the correct image is used. It uses two images one image contains secret informati on, in visual cryptography it is not possible to retrieve the secret information from one of the images, both transparent images are required to reveal the information. To print two layers into the transparent sheet is the simplest way to implement Visual cryptography (jeng shying pan, Hsiang cheh Huang and L. C. Jain, 2004). If the random image contains random pixel then it can be seen as a onetime pad system and will offer unbreakable encryption. These two layers slide over each other until they are correctly aligned where the hidden information appears. This type of visual cryptography which restores the image by stacking some significant images together is known as extended visual cryptography. Generally, visual cryptography suffers from the deterioration of image quality. The basic two cryptography models consists of a secret message encoded into two transparencies, one transparency representing the cipher text and the other acting as a secret key. Both transparencies appear to random dots when inspected individually and does not provide any information about the original clear text. By carefully aligning the transparencies the original message is reproduced (Borivoje Furht, Edin Muharemagic and Daniel socek, 2005). The original decoding is accomplished by the human visual system. Visual cryptography scheme is a visual secret sharing problem in which the secret message is viewed only in black and white pixels. Each pixel in the original image is represented by at least one sub pixel in each of the n transparencies or shares generated. Each share is comprised of collection of m black and white sub pixels where each collection represents a particular original pixel. The contrast of Visual Cryptography Scheme is the difference between the minimum number of black sub pixels in a reconstructed (secret) black pixel and the maximum number of black sub pixels in a reconstructed (secret) white pixel (Kiyoharu Aizawa, Yuchi Nakamura and Shinichi Satoh, 2004). The m ain instantiation of visual cryptographic realizes a cryptographic protocol called secret sharing. The important thing in secret sharing is it relies on a human visual system to perform the decryption. In a conventional secret sharing a secret shared among n participants can pull their shares and recover the secret but the subsets of the forbidden can obtain no information about that. Visual secret sharing schemes inherits all applications of conventional secret sharing schemes most notably access control. An example of the encoding of white and black pixels in a 2 out of 2 scheme can be seen in Figure 1. Here two shares out of the two generated would be needed to recover the original image. Since only two shares are generated, n = 2. White box represents a single white or black pixel in the original image. Sub pixel assignments that would be given to shares #1 and #2 respectively. The number of sub pixels per share used to represent the original pixel is four Finally, the overall visual effect when shares #1 and #2 are correctly aligned on top of one another. Notice that when the shares in this example are combined the original black pixel is viewed as black; however, the original white pixel takes on a grey scale. The structure obtained from either white or black pixel representation can be described by an n. Similar to the area of the secret sharing, more generally structures have been studied in the visual cryptography. The basic model of the visual cryptography consists of a sever al umber of transparency sheets. On each transparency a cipher text is printed which is identical from random noise. The hidden message is reconstructed by stacking a certain number of the transparencies and viewing them. The system can be used by anyone without any knowledge of cryptography and without performing any cryptographic computations. Naor and Shamir have developed the Visual Secret Sharing Scheme (VSSS) to implement this model [Naor95] (Mizuho Nakajima and Yasushi Yamaguchi, 2002). Thus, from the above discursion it can be stated that Visual cryptography is a special technique used to hide information in images in such a way that it can be decrypted by the human vision when the correct image is used. It is a simple and clear scheme that can partition the secret image into a number of shadow images and the dealers can distribute these shadow images to participants. The Visual cryptography scheme makes use of human visual system for recovering secret images by staking vari ous shadow images. 2.3. Importance of Visual Cryptography Visual Information system importantly elaborates the diligences scope of information systems and deals with the multimedia operating system which is supported by multimedia hardware and high bandwidth network. These are text oriented which provides reports, decision-making information and documents for all levels of hierarchy in the organization (Carlo Blundo and Stelvio, 2005). With the increase in multimedia platforms, visual information has become more available with the advancement of information technology; contact through internet has increased rapidly. Visual information system requires many kinds of facilities for effective visual information presentation and visualization. This system actually supplies inter related visual and multimedia information to support the operations, management and decision making functions in an organization. As internet can be accessed by everyone and anyone can easily access the information and transmit it without any protection there is possibil ity of grabbing the information as it became secondary data. So in order to avoid hacking of sensitive information, it should be encrypted before transmission (Yongfei Han, 1997). In order to protect the information Diffie and Helman (D-H) proposed a key agreement scheme that is implemented when two parties agree on a common session key. This key agreement also helps in improving the reusable process. This technique is utilized to calculate a common image for encryption and decryption with two parties. The D-H algorithm does not encrypt data or make a digital signature. This is exclusively used for the generation of shred secrets. The DH key agreement can be split into three parts; they are parameter generation that generates non secret public value and is expensive process, next is phase1generatres two key exchange values for the parties and phase2 is the originator and recipient that computes the functions in the given image. DH key agreement has a nice property that it is not sen sitive to off-line attacks but it is sensitive to man-in-the-middle attacks. There after Naor and Shamir proposed a methodology named visual secret sharing that provides secrecy to the information and avoids illegal activities (Jeng-Shyang Pan, Hsiang-Cheh Huang and L. C. Jain, 2004). This process is called as Visual Cryptography. This process provides secrecy by partitioning the secret digital image into several shadow images that are recovered by the human visual system by piling all those images together. It is secured technique where the data cannot be traced by others. In classic secret sharing, algorithms for splitting and sharing secret information are a stem of cryptography. In the most general case, their objective is to generate such parts for the data and that could be shared by multiple authorized persons. This problem of splitting information in a manner allowing its reconstruction by a certain n-person group interested in the reconstruction of the split information. Al gorithm solutions developed to achieve this objective and at the same time none of the groups of participants in such a protocol, whose number is lesser than the required m persons. It leads to opposing to read the split message. The algorithms for dividing information make it possible to split it into chunks known as shadows that are later distributed among the participants of the protocol. So that the shares of certain subsets of users collective together and these are capable of reconstructing the original information. There are two groups of algorithms for dividing information, namely, secret splitting and secret sharing. In the first technique, information is distributed among the participants of the protocol, and all the participants are required to put together their parts to have it reconstructed. A more universal method of splitting information is the latter method, i.e. secret sharing (Marek R. Ogiela and Urszula Ogiela, 2009). Thus, from the above discursion it can be sta ted that visual cryptography plays a vital role in securing the data and also in sharing the secret message as the data transferred through internet has been increased. rapidly. Advantages of visual cryptography Visual cryptography is simple to be implemented. Encryption incase of visual cryptography does not require any hard problem dependency. Specifically decryption algorithms are not required because a person aware of cryptography can easily decrypt the message. Cipher text can be Fax or e-mail in case of visual cryptography 2.4. Security analysis on images with the previous technologies The security analysis is the major aspect of the encryption. Analysis to the field of security will encounter the serious obstacle that deal is by nature not an exact science. The previous technologies which where there before the D-H key agreement encryption are manual encryption, transparent encryption, symmetric encryption and asymmetric encryption (Fedora Documentation Project, 2009). Visual cryptography can be seen as a one-time pad system. Then, it cannot be reused. Diffie and Hellman (D-H) key agreement method and Toral Automorphism (TA) such that visual cryptography can be reused. Both secret and symmetry-key are represented in binary image. The proposed scheme is simple and easy to be implemented for shadow images. Therefore, it can be used in many electronic business applications (Chao-Wen Chan and Yi-Da Wu, 2008). The Manual Encryption is a technique that will involve the use of encryption software. In this computer programs are used for encrypt various bits of information digitally. In this technique the encryption key is provided later in the process. The main security issues are the potential leakage through security insensible program and also the bad implementation may lead to re-encrypt with same key for same password (Bruice Schneier, 2007). Transparent Encryption is another type of computer software encryption. In this technique the data can be downloaded onto a computer to encrypt automatically. Every executable application and file created in the computer has an encrypted copy that can withstand power surges and protects information in case a computer is stolen. The security issues is the data which is automatically encrypted can be taken if the key provided is known (Cetin K. Koc, David Naccache and Christof Paar, 2001). The Symmetric Encryption is in which a letter or number coincides with another letter or number in the encryption code. This technique is commonly referred to as secret-key encryption. In this only single key is used for e ncrypting an

Gossip Girl by Cecily von Ziegesar :: essays research papers

This book is basically following the gossip of the privileged, beautiful, and filthy rich teens. While many novels have a one-person view of their story, this one allows you to understand each character’s thoughts. Welcome to New York City’s Upper East Side, where teenagers have unlimited access to money and whatever else they could ask. This book begins when the girl everyone loved to hate, Serena van der Woodsen is back from boarding school. Everyone claims she was kicked out. Blair Waldorf and Serena were best friends until Blair knew what it was like to be in the light Serena used to take up. Blair’s mother, Eleanor Waldorf, and her soon to be step-father, Cyrus Rose, threw a dinner party when Blair met the her nightmare. This was the first time Blair had seen Serena in two years. Blair knows that if Serena is around Nate, her boyfriend, she’ll end up stealing his heart. The rest of the book follows Blair’s parties and new gossip heard over Serena. Blair is on the organizing committee for the Kiss on the Lips party, when she can’t seem to find someone to print the invitations. Jenny Humphrey agrees to make them if she can have invitations for herself and her brother, Dan. Serena tries to straighten up her life by doing more extracurricular classes at Constance school for girls. She decides she might join the Interschool Drama Club where they are doing a modern version of Gone With The Wind. She later blows that off and joins another drama group. A girl named Vanessa Abram is the director of her version of War and Peace. Serena was the best person for the part Natasha, but Vanessa doesn’t want Dan, as Prince Andrei, to swoon over Serena during the play. Jenny finally convinces her brother to take her to the Kiss on the Lips party. Serena blew off the party and called Vanessa to see if she would help her make her own movie. Vanessa agrees to help and invites Serena to a bar called The Five and Dime where her sister’s band would be playing.

Invent School Program Essay

I. Introduction Some students from Bansud National Highschool – Regional Science Highschool for Region IV-B MIMAROPA with other school’s representative from different towns in Mindoro joined a seminar held on 16-17th day of April 2013 at Filipiniana Hotel Convention Hall Calapan City, Oriental Mindoro. The seminar is about on how to make a Science Investigatory Project and some topics regarding in research fields. The representative of Department of Science and Technology – Technology Application and Promotion Institute (DOST – TAPI) organized a seminar for us. The speakers for the seminar are Dr. George M. Colorado, Ms. Teresita O. De Vera, and others. In our two-day seminar the topics they discussed is about â€Å"Creativity†, †Creative, Perceptive, and Inventive Thinking†, â€Å"Ideation tools and Techniques†, â€Å"Creative Problem Solving Process†, â€Å"Invention Development†, â€Å"Prior Art Search†, an d â€Å"Intelectual Property Rights.† II. Knowledge / Learning Acquired I have knowledge on making a Science Investigatory Project because when I was on 5th grade level I joined a contest regarding on it. I also have knowledge in research fields because we have a subject about in our class about it. Based on what I learned from the seminar It is important to always ask yourself, train to think always so that your mind can easily perceive the things around our surroundings to come up a novel invention. I also learned from the speakers the difference of an invention and not. The most emphasized thing in the seminar is how to think and invent a creative Science Investigatory Project. III. Observation During our seminar I observed that our speakers have enough knowledge about the topic they are discussing. I also observed that they have freebies for us to participate in their discussion and question and answer portion. I observed that all students are interested to the topic they discussed and participated with the speakers attentively and most of all listened enough to learn. IV. Recommendations/ Suggestions I suggest that they provide a hand outs for all the participants of the seminar so that the participants or all students have notes to be compile and use it while the seminar is going on so that they don’t need to copy instead they will focused on listening to the speaker.

Inequality in our Education System Essay

Education is vital to all individuals. It is the foundation of one’s development in order to achieve personal distinction. In addition, it also equips people the capacity to properly interact with other people. Education serves as a weapon for survival. It empowers one’s capacity and provides an edge in any endeavor that one wishes to get involved in. For example, in securing a job, a decent   and impressive educational attainment is one of the qualifications necessary in order to get hired.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Schools are designed to provide the adequate needs for attaining quality education. Schools should provide competent teachers, rigorous curriculum and modern facilities and equipments. But few   Americans are aware of the massive disparity and inequality that are consuming the educational system. Although it is not proper and ideal, the social status of an individual greatly affects the quality of education that one receives (Darling- Hammond, 2008, p. 208).   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Tracking, in the area of education, recognizes the gap between the low-income, minority students and their well-off peers. Ethnic and linguistic minority students coming from low-income background oftentimes only afford admission to general and vocational courses, thus decreasing their chance, if not totally depriving them from pursuing college education (Mehan and Hubbardm, 1999, n.p). Schools with high concentration of low-income and minority students receive fewer and poor quality learning resources than the other schools within the same district (Darling- Hammond, 2008, p. 208).   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Along with medical assistance and social welfare, ideally the education sector should be alloted with a larger portion from the state budget and should be appropriately divided among all the schools. But ironically, educational fund in the United States has also been unequally distributed to all schools. 10% of the wealthiest school district in the most industrialized country spend 10 times more than the 10% least fortunate. The number of poor and minority students are definitely higher in the least funded schools, mostly located at the central cities and rural areas, which is lowly funded than the schools in the suburban districts. Recent study shows that Alabama, New Jersey, New York, Louisiana, and Texas and schools with higher ratio of students of non-White American descent receive fewer resources than schools serving a greater number of White Americans (Darling- Hammond, 2008, p. 208).   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   To address the issue of racism within the educational system, the idea of hidden curriculum was coined. Hidden curriculum pertains to the messages passed on by the organization or pedadogical institution apart from their public statements. The hidden curriculum is aimed to teach the students of school routines and to enable students in getting along in school and in the society in general. The messages in hidden curriculum may complement or contradict each other. In a way, it opens the minds of students to the possibility that some of the innate principles and natural laws enclosed within the democratic political system, may not at all times be practiced (Cornbleth. 2008, n.p).   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Earlier studies proved that hidden curriculum conveyed in public and private schools were different. Public schools mainly focuses on academic classrooms with an emphasis on things like race, ethnicity, disability, and gender or sexual orientation as well as social class, politics, and culture (Cornbleth, 2008, n.p).   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Over the years, we have overcome indecency caused by racism. As our culture succumbs to the tenets of globalization, people of different faces and races have been drawn closer towards each other. And this trend would ideally suggest equality among people born out of different ethnicities. The irregularities in our education systems rooted from unjust   policies have caused inequality in our schools.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Tracking, has kept the students separated from others based on their skin color and income. Tracking is therefore a form of racism, wherein students coming from different race and low-income background can never avail of the same oppurtunities, benefits and treatment that other students get. School funding policies branch from tracking, where schools serving more students who they believe are from inferior color and race, receive lesser funds than other schools. And last, hidden curriculum disposes messages that rationalized disparity among students.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   In any way, the school shall serve as an institution where values and culture formation is hastened. But if an important and delicate institution like schools inculcate disparity amongst the people, then students and the whole society will be deprived of the rights that everyone must equally enjoy. References Cornbleth, Catherine. (2008). Hidden Curriculum. Retrieved May 3 2008 from http://education.stateuniversity.com/pages/1899/Curriculum-School-HIDDEN-CURRICULUM.html Darling-Hammond, Linda. (2001). Inequality in Teaching and Schooling: How Opportunity Is Rationed to Students of Color in America. In The Right Thing to Do, The Smart Thing to Do Enhancing Diversity in the Health Professions (pp. 208-233). National Academy. Mehan, Hugh and Lea Hubbard. (July 1999). Tracking â€Å"Untracking†: Evaluating the Effectiveness of an Educational Innovation. Retrived May 3 2008 from http://crede.berkeley.edu/research/tier/rb3.shtml

A Dolls House Essay Example

A Dolls House Essay Example A Dolls House Paper A Dolls House Paper One of A Dolls Houses central theme is secession from society. It is demonstrated by several of its characters breaking away from the social standards of their time and acting on their own terms. No one character demonstrates this better than Nora. During the time in which the play took place society frowned upon women asserting themselves. Women were supposed to play a role in which they supported their husbands, took care of their children, and made sure everything was perfect around the house. Work, politics, and decisions were left to the males. Norasfirst secession from society was when she broke the law and decided to borrow money to pay for her husbands treatment. By doing this, she not only broke the law but she stepped away from the role society had placed on her of being totally dependent on her husband. She proved herself not to be helpless like Torvald implied: you poor helpless little creature! Noras second secession from society was shown by her decision to leave Torva ld and her children. Society demanded that she take a place under her husband. This is shown in the way Torvald spoke down to her saying things like: worries that you couldnt possibly help me with, and Nora, Nora, just like a woman. She is almost considered to be property of his: Maynt I look at my dearest treasure? At all the beauty that belongs to no one but me -thats all my very own? By walking out she takes a position equal to her husband and brakes societys expectations. Nora also brakes societys expectations of staying in a marriage since divorce was frowned upon during that era. Her decision was a secession from all expectations put on a woman and a wife by society. Nora secessions are very deliberate and thought out. She knows what society expects of her and continues to do what she feels is right despite them. Her secessions are used by Ibsen to show faults of society. In thefirst secession Ibsen illustrates that despite Related Papers Doll House A Dolls House. Synopsis Theme of a Dolls House Linde and Nora Analysis of a Dolls House The Doll House A Doll’s House Play Searching for a Hero in Ibsen’s A Doll’s House Why does Torvald constantly reprimand Nora for her wastefulness and foolishness while simultaneously supporting her behavior? How to cite this page Choose cite format: A Dolls House. (2018, Apr 27). Retrieved from https://paperap.com/paper-on-a-dolls-house-4/'>APA "A Dolls House." PaperAp.com, 27 Apr 2018, https://paperap.com/paper-on-a-dolls-house-4/'>MLA PaperAp.com. (2018). A Dolls House. [Online]. Available at: https://paperap.com/paper-on-a-dolls-house-4/[Accessed: 21 Sep. 2019]'>Harvard "A Dolls House." PaperAp.com, Apr 27, 2018. Accessed September 21, 2019. https://paperap.com/paper-on-a-dolls-house-4/'>Chicago "A Dolls House." PaperAp.com, 27 Apr 2018, https://paperap.com/paper-on-a-dolls-house-4/'>ASA "A Dolls House," PaperAp.com, 27-Apr-2018. [Online]. Available: https://paperap.com/paper-on-a-dolls-house-4/. [Accessed: 21-Sep-2019]'>IEEE PaperAp.com. (2018). A Dolls House. [Online]. Available at: https://paperap.com/paper-on-a-dolls-house-4/[Accessed: 21-Sep-2019]'>AMA A Dolls House. (2018, Apr 27). Retrieved from https://paperap.com/paper-on-a-dolls-house-4/ Copy to clipboard A Pages:4 Words:826 This is just a sample.To get a unique paper Hire Writer Want to get a price estimate for your Essay? Deadline Paper type Essay (Any Type) Admission Essay Annotated Bibliography Argumentative Essay Article Review Book/Movie Review Business Plan Case Study Coursework Creative Writing Critical Thinking Presentation or Speech Research Paper Research Proposal Term Paper Thesis Other Article (Any Type) Content (Any Type) Q&A Capstone Project Dissertation Lab Report Scholarship Essay Math Problem Statistic Project Research Summary Assignment Dissertation chapter Speech Dissertation chapter: Abstract Dissertation chapter: Introduction Dissertation chapter: Hypothesis Dissertation chapter: Literature Review Dissertation chapter: Methodology Dissertation chapter: Analysis/Results Dissertation chapter: Discussion Dissertation chapter: Conclusion Dissertation Proposal Thesis Statement Thesis Proposal Application Essay Pages 550 words(double spaced) 126 writers online Check Price A limited time offer! Get custom paper sample written according to your requirements urgent 3h delivery guaranteed Order now A Dolls House Paper A Dolls House by Henrik Ibsen and Miss Julie by August Strindberg are two plays, the first from 1879 and the latter from 1888, which portrays the life and role of women at their time in society, as both have as their main characters two women Nora Helmer and Miss Julie. Still, the role of women in the two plays is shown to be different. Strindberg, in one hand, conveys in Miss Julie that women are inferior in the society, as he pictures them as a less important form of human beings. In the other hand, Ibsen portrays Nora, at a first look, to be a standard innocent wife showing women to be plain wives, mothers and working at home at the eyes of society. In order to show the need for change, Ibsen illustrates and emphasizes the subordination of women in the social pyramid. The purpose of this essay is to make a comparative analysis in order to understand the lives of these two women and the roles theyve taken up in each play. In A Dolls House, Nora is a housewife married to Torvald Helmer, and she stays at home with her children and managing the household. This is the typical life of a standard wife at that time. Ibsen leads on the play, penetrating and unveiling Nora in a subtle way conveying a huge effect. At the beginning he illustrates Nora to be taking the most normal life, and Torvald to be the husband who goes to work, and earns the money to support his family the usual patriarchal society of that time. Nora just seems to be like a doll, as perfect a wife and mother can be, and innocent too, as she is completely dependent on her husband. She also has a childish behavior towards Torvald as she speaks to him in a foolish way Pooh, we can always borrow till then, at other times she has small attacks of disobedience and she is irresponsible in an immature way. Oh, do, Torvald please, please do! Then Ill wrap it in a pretty gold paper and hang it on the Christmas tree. Wouldnt that be fun? The role of men and women can be seen to be different at this point since the men is the one earning the money through his work and the wife spends it on house duties. Therefore Torvald is able to manipulate Nora because he is the one in control of the money. Just like your father always on the look-out for all the money you can get, but the moment you have it, it seems to slip through your fingers and you never know what becomes of it. Well I must take you as you are its in your blood. Oh yes, Nora, these things are hereditary. Nora appreciates the way that women are able to conquer things by using there feminine seducing power, hence she uses this as a way to diminish her husbands supremacy. [not looking at him playing with his waistcoat buttons]: If you really want to give me something, you could well, you could As the conflicts in the play arise, it can be clearly seen that Noras primary struggle is against Torvald that is a selfish and oppressive husband, which represents a group that have masculine ideas towards society. For that reason it can be conveyed that the play suggests the inferiority of women beyond men. Torvald treats Nora as if she was a child, he doesnt take her seriously and therefore she may never stand in a position to contradict him as it is conveyed by the following quote: Didnt Little Sweet-Tooth just look in at the confectioners? Nevertheless as we discover more about Nora, it is suggested that she isnt as innocent and childish as she seems to be. It is reviewed that Nora, for the first time throughout the play took an action by herself. She faked her fathers signature in order to borrow money and pay the trip with her husband that was very ill. Even though what Nora did is illegal she is proud of it: I have something to be proud of. It was I who saved Torvalds life. She believes it was done for a good reason and therefore the crime should be ignored. By the end of the play the main conflict concerning Nora facing men arises and as a consequence she leaves Torvald to go make something out of her life. Nora believes that she has been acting throughout her life in order to make other people happy, like Torvald and her father, but now she is no longer carrying this further so she tells her husband everything that she feels. I have been performing tricks for you, Torvald. Thats how Ive survived. You wanted it like that. You and Papa have done me a great wrong. Its because of you Ive made nothing of my life.

Benefits of Tuition Reimbursement Essays

Benefits of Tuition Reimbursement Essays Benefits of Tuition Reimbursement Essay Benefits of Tuition Reimbursement Essay | Benefits of Tuition Reimbursement| | Latoya Freeman| | 3/17/2011| Benefits of Tuition Reimbursement Programs I am here to inform you on why adding tuition reimbursement for bachelor’s degrees in business and communication will benefit our company. Since the company has already approved a budget for this expansion, and financial costs are of no concern, we should put this program into action. I think this program will be very beneficial to our company. I believe this program will open up a whole new world of opportunities for our employees. People who earn their degree have more professional opportunities than those who don’t. They are open to a wide range of different careers, they have a higher earning potential, and this program will benefit our company. In today’s economy it is very hard to find a decent paying job without a college degree. The cost of living is on the rise and minimum wage is just not a valid source to provide for a comfortable living. We are always stressing to our employee about how much we value them and care about their well being. Why not help to provide them with the opportunity of a lifetime. It is the dream of many of our employees to obtain a college degree, but because of different circumstances, they are unable to fulfill that dream. We have a lot of hard working individuals who have the potential to grow within our company and the thing that is holding them back is their lack of education. By offering to help with the expenses of tuition and books will show our employees that we are aware of their potential and we care about their success and the success of the company. This benefit will encourage those employees who have the desire to further their education do so and thus providing a loyalty to our company in appreciation. It is no secret that those who earn their degree have more professional opportunities available to them. We can’t expect all of our good workers to remain with our company with low pay. Some of our employees are enrolled as college students and earning their degree already. Do we really want to risk losing a dedicated worker to another company because they can’t see any future growth with our company? If we offer this benefit to our employees they will able to live a successful life just like the rest of us. They will have the opportunity to become a supervisor, a manager, and maybe even President one day. I don’t think we should deny our workers this opportunity, especially if we have room in the budget to cover it. This would seem a bit selfish on our part. Some may think that offering this program will eventually cause the company to spend more money. But I believe that paying for our current employee’s tuition will save the company money. If you think about the money that will be spent to hire a new employee with the degree that our experienced employee is trying to obtain, you will eventually spend more time and money on the new hire. They will need to be trained and that costs time as well as money. Whereas, our employee that is earning their degree can have the opportunity to obtain extra training while they are still in school. Let’s think of the positives here, we will provide our employees with the opportunity to work, earn their degree, and receive on the job training for future promotions. One of the main reasons that people make the choice to further their education is to increase salary potential and advancement in their careers. Individuals who go that extra mile to obtain their degree are rewarded with exceptional employment opportunities. If we offer assistance for those who want to explore the business field, it will give our company a major boost as opposed to our major competitors. In most cases a business degree is required for executive and senior management positions. Some companies will not even want to look at an applicant’s application if they didn’t have a degree in business. (businessmajors. about. com †º †º MBA Program Information) There are many different types of employment opportunities available for those who hold a business degree. Think of all of the wonders this could add to our business. Many business programs offer an education in general management along with a more specialized curriculum. This form of education is relevant to all industries and sectors. It will be valuable regardless of the career that is chosen after graduation. The different jobs that are able to be performed by an employee who has a business degree are endless. They can perform many jobs in human resources, operations management, accounting, marketing, etc. In this case, we can’t lose. We will have the opportunity to have an employee that is well rounded. They can perform operational duties as well as business and other human resource tasks. Overall, I believe this program will benefit our company as a whole. We won’t have to waste money to hire new people to take care of any business that we may have because we already have a qualified person with a business degree. By providing our employees with this benefit we will have more educated employees. Employees that take advantage of tuition reimbursement tend to stay with their company longer. This establishes loyalty between employer and employees. Another advantage of offering tuition reimbursement is that the company will be given a tax deduction. Up to $5,250 annual maximum, an employer’s reimbursement program costs are tax deductible. Essentially, after the tax benefit, the employer pays very little to offer this benefit. Since the costs balance out and the company reaps the benefits of a smarter workforce, it’s a highly desirable win- win scenario for the company. (distancelearn. about. com †º paying for school) I think this is a great program that will be very beneficial to our company. We as employers should see this as an incentive for our employees to go to college. This will make them more productive as well as more knowledgeable, thus adding to the success to our business. We need our employees to be smart, diligent, and very hardworking individuals, and by earning their degree in a field related to their job, it will allow them to be better employees. I also believe it will encourage them to gain a higher respect for our company. They will make us more money and in turn we can pay them a little more to work harder. We must remember that education is the key to success. By adding this benefit I believe in turn we will have a much more successful company. References: businessmajors. about. com †º †º MBA Program Information distancelearn. about. com †º paying for school

Start Learning Spanish With Basic Lessons

Start Learning Spanish With Basic Lessons Spanish is one of the most-used languages in the world. Its also one that is relatively easy for English speakers to master. There are many reasons why you might want to learn Spanish. Maybe youre studying the language at school or planning a trip to a Spanish-speaking country. Whatever it may be, there are a number of basics that will help you get started. The Spanish Alphabet Words are made up of letters, so its only logical that you begin by learning the Spanish alphabet. Its very similar to English, with a few exceptions, and there are some special pronunciations youll need to know. Many languages- Spanish included- use stress and accent marks to guide pronunciation. Since English is one of the few that doesnt, this can be one of the more challenging aspects of learning Spanish. Words and Phrases for Beginners Rather than dive right into the finer points of Spanish grammar, lets start with some basic vocabulary lessons. By learning simple things like the words for various colors and family members, you can feel a little sense of achievement right from the start. Greetings are among the first lessons in any Spanish class. When you can say hola, gracias, and buenos dias, you have a great start to any conversation. Likewise, if your ultimate goal is simple conversations to use on vacation, you may need a few common phrases. Asking for directions, for instance, can be very important for your travels. You might also need to read or ask for the time to keep your itinerary on track. Its not a bad idea to give the four seasons a quick study, either. Working With Nouns in Spanish Two rules stand out when using Spanish nouns. The most unique to English speakers are the masculine and feminine forms. Every Spanish noun has an inherent gender assigned to it, even if the subject is of the other gender. Quite often, the feminine will end with an -a  and will use the articles  una, la, or las  rather than the masculine  un, el, or los. The other rule of Spanish nouns comes into play when we are using the plural form. This tells you when to add an  -es  and when you can simply attach as  -s to the noun. Further, the adjectives attached to the nouns must agree with either the singular or plural form. Spanish Pronouns Are Important Subject pronouns include words like  I, you,  and  we, which we use all the time to form sentences. In Spanish, subject pronouns are  yo, tà º,  Ãƒ ©l, ella,  etc. Theyre used quite often to replace the subject of the sentence, but there are a few things you need to remember. For instance, Spanish has both a formal and informal version of  you. With someone youre familiar with, you can use  tà º,  but formally its proper to use  usted. In addition, there are certain times when its okay to omit the pronoun. Essential Spanish Grammar Other basic parts of Spanish grammar have their own rules that youll want to study. Verbs, for example, need to be conjugated to match the past, present, or future tense of the sentence. This can be difficult for students, but it is similar to adding the  -ed  and -ing  endings in English. Muy  means  very  and  nunca  means  never  in Spanish. These are just two  of the many adverbs you can use to explain what something is like and add emphasis. Adjectives in Spanish can be a little tricky. Many times, these descriptive words are placed before a noun, but there are other circumstances when they come after it. For example,  the red car  is  el coche rojo, with  rojo  being the adjective that describes the noun. One other very important part of speech is the preposition. These are short connective words like  in, to,  and  under. In Spanish, they are used much like they are in English, so learning prepositions is often a simple matter of studying the new words.