William Shakespeare Argumentative Essay Example For Students

William Shakespeare Argumentative Essay William Shakespeare wrote the play The Taming of the Shrew in the 1590s. In these times it was popular in Elizabethan England to ridicule Catholics. The Italian setting allows the playwright to snipe at Italian Catholics for comic effect. It is a comical play in contrast to a number of Shakespeares other works, which are classed as historical or tragedy. It is a story within a story. The background plot is about a drunken man who is made to believe he is a lord after being thrown out of the pub one night. The second and main story is about the shrew, Katherina. The label of a shrew is given to Katherina because she is constantly nagging and moaning at people in Padua. This connects her with a Shrew because these mammals make a sexual whining noise during the mating season. This is one of the many sexual innuendos we are given throughout the play, making it comical for both an Elizabethan and modern audience. We will write a custom essay on William Shakespeare Argumentative specifically for you for only $16.38 $13.9/page Order now Katherina and Petruchio are newly married, which many characters find shocking as no-one appears to like Katherina. Now Katherina is married her perfect young sister Bianca is free to marry; the agreement with their father was that Katherina had to marry first. Bianca means white in Italian, which has connotations of innocence and purity.  Since the day of their marriage Petruchio has been acting in a strange fashion. Arriving at the wedding extremely late, on a donkey, dressed in rags was not the ideal way to charm his woman. Then he whisks a tired, hungry Katherina off to his home in Verona (miles from Padua) straight after the ceremony. While on route, Grumio has began to tell the other servants back at the house what Katherina is really like. Grumio tells Curtis of Katherinas violent ways Whose hand- she being now at hand- them shalt soon feel. This suggests that Grumio and the other servants are going to be struck by Katherinas wicked hands. The play is quite physical in nature, and violence is often used for comical purposes. Grumio warns the servants of her being in a rotten mood due to her falling from her horse getting very muddy and Petruchio not really showing a care in the world. So Petruchio and Katherina have returned home to Verona, with the servants expecting an unpleasant mistress to return with their master. The servants seem to be wrong, as the Petruchio they used to have a laugh and a joke with had changed, and this fierce woman was fine, in fact the fierce person was Petruchio. As soon as he walked through the door he was moaning; Where be these knaves? A starving Katherina is finally sat at the table ready to eat after her long tiring journey. The food is plated and brought to the table, appearing to be a lovely piece of mutton from Catherines point of view. However, from Petruchios twas burnt and dried away. It was fine but for some reason Petruchio is acting strangely and not allowing Katherina to eat. As the servant clears the meat, Petruchio trips him again making more work for the servants. He is killing her in her own humour (as noted by Peter). Basically Petruchio is doing to others what Katherina used to do to, allowing her to experience the consequences of such actions. Hes giving her a taste of her own medicine. Shakespeare uses juxtaposition here, with Petruchio being kind and considerate to Katherina while he is repeatedly being horrible to the servants. In the process of Petruchio being cruel to the servants, he is also depriving Katherina of vital wants and needs like sleep and food. The way Petruchio acts is unusual and Katherina doesnt seem to like it. She tries to protect the servants patience I pray you begging Petruchio to take it easy on his servants. Now Petruchio has gained power over the shrew, allowing her to appear kind but making her pray for his good will. .u2c711f521233a445a2b4b9e2eb99636b , .u2c711f521233a445a2b4b9e2eb99636b .postImageUrl , .u2c711f521233a445a2b4b9e2eb99636b .centered-text-area { min-height: 80px; position: relative; } .u2c711f521233a445a2b4b9e2eb99636b , .u2c711f521233a445a2b4b9e2eb99636b:hover , .u2c711f521233a445a2b4b9e2eb99636b:visited , .u2c711f521233a445a2b4b9e2eb99636b:active { border:0!important; } .u2c711f521233a445a2b4b9e2eb99636b .clearfix:after { content: ""; display: table; clear: both; } .u2c711f521233a445a2b4b9e2eb99636b { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .u2c711f521233a445a2b4b9e2eb99636b:active , .u2c711f521233a445a2b4b9e2eb99636b:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .u2c711f521233a445a2b4b9e2eb99636b .centered-text-area { width: 100%; position: relative ; } .u2c711f521233a445a2b4b9e2eb99636b .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .u2c711f521233a445a2b4b9e2eb99636b .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .u2c711f521233a445a2b4b9e2eb99636b .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .u2c711f521233a445a2b4b9e2eb99636b:hover .ctaButton { background-color: #34495E!important; } .u2c711f521233a445a2b4b9e2eb99636b .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .u2c711f521233a445a2b4b9e2eb99636b .u2c711f521233a445a2b4b9e2eb99636b-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .u2c711f521233a445a2b4b9e2eb99636b:after { content: ""; display: block; clear: both; } READ: Othello Shakespeare EssayDuring the next section of the play we are given an insight into Petruchios strange ways during a soliloquy. Petruchio reveals to us that he is trying to man his haggard, by trying to tame his wild hawk (Katherina). He refers to His falcon is now passing sharp and empty, which again links his wife to animals. In the Elizabethan chain of being, animals were below the level of humans. He is sort of suggesting she is at the bottom of the natural order acting like an animal and needs to be taught how to become a proper human at the top end of the scale. Petruchio is trying to confuse Katherina and in doing so is making her obey patriarchal society, whe re she needs to obey Petruchio at all times. Also as a soliloquy is just between Petruchio and the audience, it creates dramatic irony. The servants have no idea that Petruchio is trying to do this to tame Katherina. They simply think that their master has changed. One reason I can think for Petruchio not revealing his plan to the servants, is so it looks more realistic. He doesnt want all the servants to be playing along and make it look like a setup. The fact the servants do not know Petruchios plans adds to the comic effect of the scene. The newly married couples are reunited for a big feast for Lucentio and Biancas celebration. Katherina, is still being thought of as a shrew from her previous time in Padua, and the other wives continue joking about Katherinas shrewish behaviour: Your husband being troubled with a shrew. The widow displays an aggressive nature, daring to argue with the male characters by passing judgement on them. Bianca also reveals a rude and abusive side to her character again questioning the men like the widow. This is a contrast to her supposedly being pure. I mean to shift my bush. Her language has sexual connotations. The women are tested to see their obedience to their husbands and for once Katherina has come out as the most obedient, the most tamed. She came straight to her master unlike the other two mistresses. Love, fair looks true obedience. Katherina has just proved to the other couples that she is now playing the correct role of a wife. Loving and willing to adhere to her husbands every need. As if Katherina hasnt proved herself enough, she goes and rubs salt into the other womens wounded pride my mind hath been as big as one of yours. This acknowledges she has previously acted as a misguided shrew but has since changed her act.  I believe Petruchio has tamed Katherina. Initially I didnt believe he had managed and thought she was just putting on an act in front of her new household, but when she acknowledges her behaviour (in her final speech) I believe she has changed. All the effort Petruchios put in throughout the play had paid off and he finally tamed the shrew.

Exxon Valdez Essays - Exxon Valdez Oil Spill, Oil Pollution Act

Exxon Valdez Essays - Exxon Valdez Oil Spill, Oil Pollution Act Exxon Valdez INTRODUCTION On March 24, 1989 at 4 minutes past midnight, the oil tanker ExxonValdez struck a reef in Alaska's breath-taking Prince William Sound. Instantaneously, the quiet waters of the sound became a sea of black. We've fetched up - ah - hard aground north of Goose Island off Bligh Reef, and - ah - evidently leaking some oil, Joseph Hazelwood, captain of the ship, radioed the Coast Guard Marine Safety Office back in Valdez. That some oil turned out to be a total of 11,000,000 gallons of crude oil leaking from the ruptured hull of the ship. By the time a containment effort was put forth, a weather storm had helped to spread the oil as much as three feet thick across 1,400 miles of beaches. A little over ten years have passed since the largest oil spill and the greatest environmental disaster in American history, but the waters and its surroundings are still recovering. At first, many people repeated what was then thought as common knowledge, oil dissipates, nature heals quickly, all will be well in a year or two. This has not been the case with the Exxon Valdez. This massive 987-foot tanker has left a lingering, long-term effect on the natural habitat that surrounds these pristine waters, along with an enormous socio-economic effect that has left many people wondering when and where the next oil spill will be. Many associated with the recovery process, and its more than one hundred projects per year, say it will take longer than a human lifetime to determine if a full recovery is possible (Fine 1999). RESULTS AND DISCUSSION The Exxon Valdez oil spill was initially thought of as a two to three year clean-up project. As time went ahead, scientists and clean-up crews realized that it would take a longer period of time and require a lot more effort than originally planned. Up to this point, the oil has contaminated a national forest, four wildlife refuges, three national parks, five state parks, four critical habitat areas and a state game sanctuary, which spreads along 1,400 miles of the Alaskan shoreline. Recent scientific studies show that the oil continues to wreak havoc among many spawning salmon, herring, and other species of fish. This is even more devastating when considering that much of the wildlife around the sound is dependant on the high calorie, high fat content of the herring as their prime food source. Among the many casualties were 2,800 sea otters, 300 harbour seals, 250 bald eagles, as many as 22 killer whales, and an estimated quarter-million seabirds. It is unclear how many billions of salmon and herring eggs and intertidal plants succumbed to the oil smothering. Within an ecosystem, each living thing depends on other living things. That means that when the fish died in Prince William Sound, there was less food for the seals that normally eat them. As those seals died, there was less food for the killer whales that eat seals (Knickerbocker 1999). This has led to a domino effect within the food chain, victimizing many of the animals surrounding the area. Intertidal mussel beds are still contaminated to this day. Twenty-three species of wildlife were effected by this oil spill, and only two species, the bald eagle and the river otter, have fully recovered. The species that are well on their way to a comeback include pink salmon, Pacific herring, sea otters, mussels, black oyster catcher, common murre, marbled murrelet, and sockeye salmon. As with any environmental disasters, there are some animals that are showing little or no clear improvement since the spill occurred. This group includes harbour seals, killer whales, harlequin ducks, common loons, cormorants, and the pigeon gullomot. In some areas, that have been hardest hit by the oil spill, many of the species have an elevated level of mortality. Even though the Exxon Valdez is the most-studied oil spill in world history, it is also a particularly difficult one to research because of the lack of baseline data on the ecology of Prince William Sound (Birkland 1998). Among all the animal casualties, there is another victim, people. Thousands have been forced to bare the consequences of the Exxon Valdez oil spill. Throughout the years, the waters of Alaska have

The analysis by Steel Tube division of Engineering Products Plc Assignment

The analysis by Steel Tube division of Engineering Products Plc accountant - Assignment Example Center of discussion in this paper is a financial analyst for Steel Tube division of Engineering Products Plc named Roger Davis. He is having a tough time convincing the management for a project proposal. The analysis by his accountant and the additional information obtained from other sources has added to his woes. Roger Davis needs to convince his managing director about the viability of a new proposal for computer numerically controlled (CNC) milling machine. The MD is not ready to spend money on the project unless it can start yielding profits within 3 years. However, the accountant’s analysis shows an overall loss for the project over the next 4 years. It won’t be prudent to expect much from the project after this period. Roger has collected a lot of additional information as well. But he has not been able to justify the viability of the project with given information. Most of the information available to Roger seems relevant at first sight. However, the consultant charges of  £18,000 have already been paid by the company. Hence, they would not make much difference to the investment decision. Also acquiring opening stock at the beginning of the year rather than considering the same at year end would have minimal impact on the decision (the impact due to time value of money would be very small as compared to other numbers) and hence should be neglected for analysis. In addition there are pieces of information which don not directly reflect the performance of the project and must be excluded for a fair evaluation. They would be discussed in greater detail in section 5. 4. Cash flow Analysis using all additional information The accountant’s analysis was quite limited. Therefore, additional information collected by Roger needs to be incorporated in the financial analysis (Johnson, Derek). The same has been done in Table 4.1. The methodology for the same is discussed here. Table 4.1: Cash Flow Analysis using Accountant’s Analysis a nd Additional Information    Year       0 1 2 3 4 Total Sales    400.00 600.00 800.00 600.00    Cost of Sales    180.00 300.00 380.00 300.00    Labour Cost    80.00 120.00 120.00 80.00    Revised Other production expenses    64.00 66.00 68.00 84.00    Depreciation    40.00 40.00 40.00 40.00    Administrative Overhead    54.00 76.00 74.00 74.00    Interest on loans    22.00 22.00 22.00 22.00    Total Cost    440.00 624.00 704.00 600.00    PBT    -40.00 -24.00 96.00 0.00    PBDT    0.00 16.00 136.00 40.00    Depreciation for Tax purpose    60.00 45.00 33.75 25.31    Cumulative Depreciation for Tax purpose    60.00 105.00 138.75 164.06    PBT (for Tax purpose)    -60.00 -29.00 102.25 14.69    PAT (for Tax purpose)    -42.00 -20.30 71.58 10.28    Net profit (for company)    -62.00 -25.30 77.83 24.97    Scrap sales 20.00 0.00 0.00 0.00 20.00    Cash benefits due to sell-off of existing machine 0.00 18.00 18.00 18.00 18.0 0    Additional advertising expenses -40.00 -8.00 -8.00 -8.00 -8.00    Consultant expenses -18.00 0.00 0.00 0.00 0.00    Reduction in sales of competing products    -60.00 -60.00 -60.00 -60.00    Net cash flow -38.00 -112.00 -75.30 27.83 -5.03

Global Credit Crunch Essay Example | Topics and Well Written Essays - 2000 words

Global Credit Crunch - Essay Example The overall financial solutions to UK clients thus would be greatly affected. (CEBR, 2008)1 Therefore it is necessary to find necessary solutions to various aspects of present global credit crisis to strengthen the UK economy. The global credit crunch has had the attention each and every human being for bad reasons. The present crisis has effected in job lay offs around the world mostly in the developed countries like USA, the UK, Japan, etc. As mentioned earlier, one of the root causes was excessive lending by the banks to the customers. In other words, the banks and other financial institutions lured the customers to borrow loan without any hassle such like low interest rates, 24 hours approval of loan, pay the installments after one year, etc. Such were the schemes offered by various banks to attract the wide range of customers mainly from housing sector.2 The banking authorities didn't even bother to check the liability of the person to whom they are lending, whether the person was able to pay back the money. The Bishop of London quoted in the Daily Telegraph that 'it is becoming clearer how far we have been mortgaging our children's tomorrow to fund our today, both financially and in our use of the finite resources of earth'.3 Looking at the past experiences of financial crisis occurred during the last millennium, it can be assumed that the process of borrowing from the financial institutions will be a Herculean task. The need to restore capital ratios and to recover the losses incurred, it is understandable the borrowers will have lesser flexibilities, less leverage, hike in interest rates and fees will soar at historical high. (John L. Moscione : p.6)4 The customers will have to face a strict scrutiny of their valuable documents before receiving loans as a process to identify previous lack luster performance by the bank officials. Implications for Lending The present crisis is the result of irregularities by the bank and financial institutions in providing loans to the customers without proper verification of their documents and checking the liability of the person. Excessive liquidity with the financial institutions was the foundation for excessive lending by the banks to rake in more customers. In a bid to acquire more customers, they offered lucrative schemes which were spontaneously grabbed by the seekers. Credit crisis was inevitable in view of real estate market boom in recent years which blew the bubble by way of irregular mortgages, unverified loans without scrutinizing the income or assets of the borrower. This facilitated borrowers to indulge in fraud and leveraging of accounts. Most of the loans were approved on the house mortgage which was another cause for real estate boom all over the world. Selling and buying of houses were on spurge, with rates touching the all time high. According to statistics from the Bank of England, total net lending to individuals in January 2009 was 1.1 billion which was lower as compared to December 2008 that stood at 2.1 billion. The total net lending secured on dwellings was 0.7 billion in January 2009 as compared to 1.8 billion in December 2008.5 It is learnt from the

Explain How Far Wilfred Owen Challenges the Notion that it is Sweet Essay

Explain How Far Wilfred Owen Challenges the Notion that it is Sweet and Noble to Die For Your Country Using The Poems Dulce et - Essay Example Even after a war ends the violent and troubling memories keep haunting a soldier’s mind. Sometimes when the soldier becomes physically disabled he is unable to carry out the normal activities of life and to such a man what remains are only the memories with which he has to live throughout. When the young children in their schools are told how noble it is to fight for one’s land and people, it might sound really righteous but the truths which unfold as one takes a closer look at the consequences of war especially on the lives of those noble doers, one is bound to be discouraged and all motivations in favor of warfare seem meaningless in front of sheer humanity. He draws out visual images in some of his poems, where the physical, and mental suffering of the troops are vividly described. In the war poems, ‘Dulce et Decorum Est’ and ‘Disabled’ he challenges the notion that dying for one’s country is sweet and noble. The poem ‘Dulce et Decorum Est’ describes just another day in the World War I when the soldiers are marching towards their place of rest but at that very moment gas bombs begin to drop around them. They hurry for their masks and weapons but some of the ravaged bodies fail to save themselves from the attack. The author writes in a personal tone and tells the readers what he witnesses as vividly as possible with frequent use of similes –â€Å"But someone still was yelling out and stumbling,/ And flound'ring like a man in fire or lime† (Owen, line9). He focuses the description now on a single person who dies in the attack and this vision continuously haunts him in his dreams later on. He gradually shifts from first person to third person and then to second person in his address. Towards the end the poet conveys to the people at home their experience of violence and distress and wishes that they could witness the same. At the very beginning he stressed upon the very appearance of the people marching towards their place of rest. He does not address the men as soldiers or warriors; rather he compares them to old beggars and hags. He even uses the metaphoric comparison between their walk and the term ‘cursed’ which he uses to describe the miserable conditions as they march through the muddle trenches. The experience seemed to have them under some kind of a curse. The poet at times uses the technique of creating a caesura or a pause in a line of the poem in order to signify the realism precisely. The language is brief and curt as he mentions ‘Men marched asleep’ (Owen,line4). This sentence makes the men look like ghost figures walking in the dark. They are so exhausted that they almost are falling asleep. The poet uses alliterations I the form of repeated words beginning with ‘l’ – â€Å"Many had lost their boots/But limped on, blood-shod. All went lame; all blind† (Owen, line4). The words indicate they were cover ed in blood and therefore the war has enveloped their physical and mental forms. The idea here is to put forth the dragging effect on the readers just as the fatigued soldiers dragged themselves towards the tent. He changes drastically the motion by using brief lines: â€Å"Five-nines/that dropped behind. Gas!/Gas! Quick boys!†(Owen, line7), which generates the effect of fast action amidst the slow movements. Suddenly there seems to be a rush for safety. The fear struck cries and bombs falling all around leads to the environment, which brings on merciless deaths that render a stomach

Network System for Secure Communication

Network System for Secure Communication Methodology: The main methodology involved behind this research project is to provide the importance of such technology from professionals and well referred articles. Some of the general interviews will be added to the project with details showing their interest towards the current technology and also the change they see in communicating with the new technology. It on the hands of the components of IP Security that contribute to this level of secure communication: The IP Security (IPSec) Driver is used to monitor, filter, and secures the traffic throughout the system. The (ISAKMP/Oakley) abbreviated as Internet Security Association Key Management Protocol performs key exchange and management functions that oversee security issues between hosts, and provide keys which can be used with security algorithms. The IP Security Policy and the Security Associations are derived from those policies that define the security environment where two hosts can communicate. The function of Security Association API is to provide the interface between the IPSec driver, the Policy Agent and the ISAKMP. The function of the management tools is to create policies, monitor IP Security statistics, and log IP Security events. The main methodologies which are under consideration for this project are Classical encryption technologies, IP sec Tunnel, IP sec VPN, Internet Key Exchange methods, Block Cipher Data Encryption, Advanced Encryption, Symmetric ciphers, Public private key functions, Digital signature etc, which have suggested me to design a better system. Implementation: The main reason behind selecting IPSec is that it so powerful that it provides security to IP layer, and also forms the basis for all the other TCP/IP protocols. This is generally composed of two protocols: Authentication Header (AH); Encapsulating Security Payload (ESP); IPSec Implementation Methods: IPSec is comprised of several implementations architectures which are defined in RFC 2401. The IPSec implementation also depends on various factors including the version of IP used (v4 versus v6), the basic requirements of the application and other factors. End Host Implementation: Implementing IPSec in all host devices provides the most flexibility and security. It enables â€Å"end-to-end† security between any two devices on the network. Router Implementation: Router implementation however is a much simpler task since we only make changes to a few routers instead of hundreds or thousands of clients. It only provides protection between pairs of routers that implement IPSec, but this may be sufficient for certain applications such as virtual private networks (VPNs). The idea will be implemented after proper testing of various available methodologies. The current strategy for implementation is as follows:. We use certain open source softwares which provide encryption and decryption methods and authentication. In the actual system, the user is asked to enter details of files to be sent and also some other details about the password and the public keys if included. The required software are used in a way which helps to run a smooth process and secure operation. CONTENTS Acknowledgement I owe many thanks to people who helped supported me in doing my dissertation. Firstly, I would like to express my immense gratitude to my respected professor Mr. Dr. XXX, YYYY University, London for his support and motivation that has helped me to come up with this project. He supported me when its needed and suggested me in understanding various methodologies in my project. He also took care of my project with attention to achieve my goal. I thank to my Institution and faculty members for giving me an opportunity to do my dissertation and also for library, computer lab facilities for doing my dissertation to achieve practical results which can resolve my project related issues. I also extend my Heart full thanks to my family friends. I owe my special thanks to my Dad and his colleagues who gave me suggestions on doing my Dissertation. Abstract In the present system the network helps a particular organization to share the data by using external devices. The external devices are used to carry the data. The existing system cannot provide security, which allows an unauthorized user to access the secret files. It also cannot share a single costly printer. Many interrupts may occur within the system. Though it is advantageous we have numerous disadvantageous, somebody writes a program and can make the costly printer to misprint the data. Similarly some unauthorized user may get access over the network and may perform any illegal functions like deleting some of the sensitive information Security is the term that comes into picture when some important or sensitive information must be protected from an unauthorized access. Hence there must be some way to protect the data from them and even if he hacks the information because he should not be able to understand whats the actual information in the file, which is the main intention of the project. The project is designed to protect the sensitive information while it is in transaction in the network. There are many chances that an unauthorized person can have an access over the network in some way and can access this sensitive information. My main topic focuses on IPSec (Internet Protocol Security) is an extension to the IP protocol specified by IETF which provides security to the IP and the upper-layer protocols and cryptography in a network sharing system. It was first developed for the new IPv6 standard and then â€Å"back ported† to IPv4. The IPSec architecture is described in the IPSec uses two different protocols AH (Authentication Header) and ESP (Encapsulating security payload) to ensure the authentication, integrity and confidentiality of the communication. It uses strong cryptography to provide both authentication and encryption services. Authentication ensures that packets are from the right sender and have not been altered in transit. Encryption prevents unauthorised reading of packet contents. [2] Cryptography is the technique used to secure the data while they are in transactions. Encryption and Decryption are two techniques used under cryptography technology. Data cryptography is the art of securing the resource that is shared among the applications. The main idea behind the design is to provide a secured communication between the networks showing network level performance practically by differentiating different operating system which can ensure the security, authenticity by considering, analyzing and testing any best available methodologies. 1. Introduction: Businesses today are focused on the importance of securing customer and business data. Increasing regulatory requirements are driving need for security of data. There have been many methods which have evolved over the years to address the need for security. Many of the methods are focused at the higher layers of the OSI protocol stack, thus compensating the IPs lack in resolving security issues. These solutions can be implemented in certain situations, but they cannot be generalized because they are particularly too many applications. For example, Secure Sockets Layer (SSL) can be used for certain applications like World Wide Web access or FTP, but there are many other applications which cannot be resolved with this type of security. A solution is required to allow security at the IP level was very necessary so that all higher-layer protocols in TCP/IP could take advantage of it. When the decision was made to develop a new version of IP (IPv6), this was the golden opportunity to resolve not just the addressing problems in the older IPv4, but also resolve lack of security issues as well. Later a new security technology was developed with IPv6 in mind, but since IPv6 has taken long time to develop, and thus a solution was designed to be usable for both IPv4 and IPv6. The technology which brings a secure communications to the Internet Protocol is known as IP Security, commonly abbreviated as IPSec. IPSec services allow users to build secure tunnels through certain networks. All the data that passes through the entrusted net is encrypted by the IPSEC gateway machine and decrypted by the gateway at the other end. The result obtained is a Virtual Private Network or VPN. This network is effectively private even though it includes machines at several different sites which are connected by the insecure Internet. Cryptography technique is used to secure the data while they are in transactions. Encryption and Decryption are two techniques which are used under cryptography technology. Data cryptography is the art of securing the resource that is shared among the applications. The Encryption and Decryption are termed as two powerful security technologies that are widely implemented to protect the data from loss and deliberate compromise. In this project the networking allows the company to share files or data without using certain external devices. Some unauthorized users may get access over the network and perform some illegal functions in certain cases like deleting files while the transaction is still on at that time encryption and then decryption techniques are implemented to secure the data. Many other attacks in cryptography are considered which lead me to research on different types of IPSec implementation methodologies in order to design the best model such that it may be suitable for the present trend of networking systems also form a platform to enable communication to the outside world. Thus in orders to implement IPSec, certain modifications are required to the systems communications routines and certain new systems processes conduct secret key negotiations. What is IPSec? An extension to the IP protocol is considered as IPSec which provides high level security to the IP and to the upper-layer protocols. This was initially developed for the new IPv6 standard and then was back ported to IPv4. IPSec provides the following security services: data origin authentication, connectionless integrity, replay protection, data confidentiality, limited traffic flow confidentiality, and key negotiation and management. It has been made mandatory by the IETF for the use of IPSec wherever feasible; the standards documents are close to completion, and there are numerous implementations. Overview of IPSec Architecture: The IPSec suite defined as a framework of open standards. The following protocols are used by IPSec to perform various functions. [2][3] IPSec provides three main facilities which are explained below: Internet key exchange(IKE and IKEv2) : This is used to set up a security association (SA) which can be done by handling negotiation of protocols and algorithms and generating the encryption and authentication keys which can be used by IPSec.[4][5] Authentication Header (AH): This is used to provide connectionless integrity and data origin authentication for IP datagrams and also provides protection against replay attacks.[6][7] Encapsulating Security Payload (ESP): This is used to provide confidentiality, data origin authentication, connectionless integrity, anti-replay service, and limited traffic flow confidentiality. [9] Both authentication and encryption are generally desired in this mechanism. Assure that unauthorized users do not penetrate the virtual private network Assure that eavesdroppers on the Internet cannot read messages sent over the virtual private network. Since both the above features are generally desirable, most implementations are likely to use ESP rather than AH. Security Association: The security Association mechanism is used for authentication (AH) and confidentiality (ESP) A one way relationship between a sender and a receiver that affords security services to the traffic carried on it. Security services are afforded to an SA for the use of AH or ESP but not both. SA identified by three parameters: Security Parameter Index (SPI) IP destination address Security protocol identifier Overview of IPSec Services and Functions: IPSec is not only assumed as a single protocol, but is rather considered as a set of services and protocols which provide a complete security solution to the IP network. These services and protocols are combined to provide various types of protection. Since IPSec usually works at the IP layer, it provides protection for any higher layer TCP/IP application or protocol without using any additional security methods, which is considered as a major strength for its implementation. General types of protection services offered by IPSec include: Encryption of user data to achieve privacy. Authentication and message integrity has to be achieved to ensure that it is not changed on route. Protection against certain types of security attacks, such as replay attacks. The ability of the devices to negotiate the security algorithms and keys required in order to meet their security needs. wo security modes called tunnel and transport are implemented to meet the various network needs. Features Benefits: IPSec is observed to be transparent by the end users. The users on the security mechanisms need not be trained. IPSec assures security measures for individuals. There is no requirement to change the software on a user or a server system. Strong security measures are applied to the entire traffic crossing the perimeter. 2. Objective: IPSec is mostly designed in order to encrypt the data between the two systems without any spoofing attacks. It is a key force of defence against internal and external attacks. However, other than these, there are many other security strategies which have prevented the security attacks. The main idea in my research is to provide a better approach to the implementation of IP Security by analyzing the present methodologies. In the implementation of this design, I am also considering different operating systems to provide a better approach towards security which can prove to be good in ideal ways. The design of such an approach is helpful in restricting any unauthorised access to the network and also helps in providing a secure and authenticated access. The main idea behind the design is to provide a secured communication between the networks independent of the operating system which can ensure the security, authenticity by considering, analyzing and testing any two best available methodologies. In my overview of RFCs available in the Internet such as Cryptography the receiver end of a particular communication channel is not aware of the sender unless the sender transmits some information with private and public keys with cipher text which can prove his authenticity. Now the receiver sends the same package with his signature and then the receiver is also authenticated mutually. Attacks may occur in different ways. There are also many ways where in such communications can be detected and using techniques like eavesdropping or sniffing or man in the middle attack. These are the three major problems for secure communications. In my research, I will attempt to design a procedure which can be easily followed in order to overcome such problems. There are many techniques available now which are better than normal communication. The major problem in such techniques is the implementation of man in the middle attack. There have been many advances to try and rectify the problems but there has always been a flaw in the design. My research is to design a system using the current technologies used to encrypt and authenticate. These techniques play a major role in the implementation of IP Security. The major interest would be in areas like encryption, decryption and authentication. Additions will be done to this research as it is implemented. The goal is to use research existing systems and to suggest a system which makes it even hard to break. It is not 100% immune to attacks but the attack may take longer to break the system than the present rate. This system will also be very safe and will be easy to use in daily life rather than something with a dozen processing steps to be followed. 2.2 SCOPE With the rapid development of Multimedia data management technologies over the internet there is need to concern about the internet there is need to concern about the security and privacy of information. In multimedia document, dissipation and sharing of data is becoming a common practice for internet based application and enterprises. As the internet forms the open source the present for all users security Forms the critical issue. Hence the transfer of information over the internet forms the critical issue. At the present situations the cryptographic techniques are used for providing ‘SECURITY. 2.3 PROJECT PERSPECTIVE The project â€Å"Network system for Secure Communication† is totally enhanced with the features that enable us to feel the real-time environment. Todays world is mostly employing the latest networking techniques instead of using stand-alone PCs. IPSec tunnelling or Encryption, information scrambling technology is an important security tool. By properly applying, it can provide a secure communication channel even when the underlying system and network infrastructure is not secure. This is particularly important when data passes through the shared systems or network segments where multiple people may have access to the information. In these situations, sensitive data and especially passwords should be encrypted in order to protect it from unintended disclosure or modification. 2.4 PROPOSED SYSTEM In this system ‘security is the term that comes into picture when some important or sensitive information must be protected from an unauthorized access. Hence there must be some way to protect the data from them and even if he hacks the information, The proposed system provides the ‘security and it does not allow unauthorized users to access the secret files. As per the ISO standards the security parameters are: Confidentiality Authentication Integrity Key distribution Access control CONFIDENTIALITY: Confidentiality is the protection of transmitted data from passive attacks. It can protect the data from unauthorized disclosure. AUTHENTICATION: A process used to verify the integrity of the transmitted data, especially a message. It is the process of proving ones identity to someone else. INTEGRITY: The sender and the receiver want to ensure that the content of their communication is not altered during transmission. KEY DISTRIBUTION: Key distribution can be defined as a term that refers to means of delivering a key to the communicating parties, without allowing others to see the key. ACCESS CONTROL: It is a ability to limit and control the access to host systems and applications via communication links. 3.Literature Review This project emphasis design and evaluates a computer-based system using appropriate process and tools. Most of the industry wide routers in the network implement their functionality in hardware and therefore we believe that hardware based routers are more efficient than a software-based router implementation besides that most of the work is in the research community which will be performed, using software-based routers utilizing off-the-shelf PCs. Various works have to be attempted which evaluates different protocol stack, however none of them use hardware-based routers, has such a wide range of metrics, and none investigated mechanisms. My research methodology emphasis surveys, forums from the internet and articles from IEEE (Institute of Electrical and Electronics EngineersorIEEE) a quantitative approach in advance technology. I also consider various other thesis and books which are best suitable for my project. Here following are the network related definitions, and few protocols from application layer, network and internet layer also discussed which actually gives clear idea of understanding the concepts. 3.1 IPSec Standards: IPSec is actually a collection of techniques and protocols; it is not defined in a single Internet standard. Instead, a collection of RFCs defines the architecture, services and specific protocols used in IPSec. Some of the most important of these are shown below: [RFC 2401] Security Architecture for the Internet Protocol (IPSec overview) The main IPSec document describes the architecture and general operation of the technology, and showing how the different components fit together. [RFC 2402] IP Authentication Header It defines the IPSec Authentication Header (AH) protocol used for ensuring data integrity and origin verification. [RFC 2403] The Use of HMAC-MD5-96 within ESP and AH Describes a particular encryption algorithm for use by AH and ESP called Message Digest 5 (MD5), HMAC variant. [RFC 2404] The Use of HMAC-SHA-1-96 within ESP and AH Describes a particular encryption algorithm for use by AH and ESP called Secure Hash Algorithm 1 (SHA-1), HMAC variant. [RFC 2406] IP Encapsulating and Security payload (ESP) It describes the IPSec Encapsulation Security Payload (ESP) protocol that provides data encryption for confidentiality. [RFC 2408] Internet Security Association and Key Management Protocol (ISAKMP) It defines methods for exchanging keys and negotiating security associations. [RFC 2409] The Internet Key Exchange (IKE) Describes the Internet Key Exchange (IKE) protocol used to negotiate security associations and exchange keys between devices for secure communications. It is based on ISAKMP and OAKLEY. [RFC 2412] The OAKLEY Key Determination Protocol It describes a generic protocol for key exchange. [RFC 2131] Dynamic Host Configuration Protocol (DHCP) DHCP allows a host to obtain an IP address automatically, as well as to learn additional information about subnet mask, the address of its first-hop router, and the address of its local DNS server. [RFC 2131; RFC 3022] Network Address Translation (NAT)- In an attempt to provide transparent routing to hosts, NAT devices are used to connect an isolated address realm with private unregistered addresses to an external realm with globally unique registered addresses. Domain Name System (DNS): It is a hierarchical naming system for computers, services, or any resource connected to the Internet or a private network. It associates various other information with domain names assigned to each of the participants. Most importantly, it translates domain names meaningful to humans into the numerical (binary) identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide. For example, www.example.com translates to 208.77.188.166. Windows Internet Name Service (WINS): It is Microsofts implementation of NetBIOS Name Service (NBNS), a name server and service for NetBIOS computer names. Effectively WINS is to NetBIOS names, like DNS is to domain names in fact its a central mapping of host names to network addresses. Like DNS it is broken into two parts, a Server Service (that manages the encoded Jet Database, server to server replication, service requests, and conflicts) and a TCP/IP Client component which manages the clients registration and renewal of names, and takes care of queries. VPN (Virtual Private Network) : It is a virtual computer network that exists over the top of an existing network. The purpose of a VPN is to allow communications between systems connected to the VPN using an existing shared network infrastructure as the transport, without the VPN network being aware of the existence of the underlying network backbone or without the VPN interfering with other network traffic on the backbone. A VPN between two networks is often referred to as a VPN Tunnel. Most VPN technologies can be separated into two broad categories, Secure VPNs and Trusted VPNs. Internet Protocol version 6 (IPv6): It is the next-generation Internet Protocol version designated as the successor to IPv4. It is an Internet Layer protocol for packet-switched internetworks. The main driving force for the redesign of Internet Protocol was the foreseeable IPv4 address exhaustion. IPv6 was defined in December 1998 by the Internet Engineering Task Force (IETF) with the publication of an Internet standard specification, RFC 2460. IPv6 has a vastly larger address space than IPv4. This results from the use of a 128-bit address, whereas IPv4 uses only 32 bits. This expansion provides flexibility in allocating addresses and routing traffic and eliminates the primary need for network address translation (NAT), which gained widespread deployment as an effort to alleviate IPv4 address exhaustion. Due to its security and flexibility entire Internet will be deployed byIPv6 in 2012 as expected. Tunnelling: In computer networks tunnelling protocol (delivery protocol) encapsulates the different payload protocol i.e., It carries a payload over an incompatible delivery-network. It can also provide a secure path through an untrusted network without any data loss. Transport Layer Security (TLS): Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide security for communications over networks such as the Internet. TLS and SSL encrypt the segments of network connections at the Transport Layer end-to-end. Encryption: In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information (in cryptography, referred to as cipher text). In many contexts, the word encryption also implicitly refers to the reverse process, decryption. Internet Key Exchange: Internet Key Exchange (IKE or IKEv2) is the protocol used to set up a security association (SA) in the IPSec protocol suite. IKE uses a Diffie-Hellman key exchange to set up a shared session secret, from which cryptographic keys are derived. Public key techniques or, alternatively, a pre-shared key, are used to mutually authenticate the communicating parties. 4.IPSec System Architecture Authentication Header and Encapsulating Security Payload are commonly called â€Å"protocols†, though this is another case where the validity of this term is debatable. They are not really distinct protocols but are implemented as headers that are inserted into IP datagrams, as we will see. They thus do the â€Å"grunt work† of IPSec, and can be used together to provide both authentication and privacy. IPSec protocols: The IPSec protocol family consists of two protocols: Authentication Header (AH) and Encapsulated Security Payload (ESP). Both these protocols are independent IP. AH is the IP protocol 51 and ESP is the IP protocol 50 Authentication Header: This is a member of the IPSec protocol suite. Authentication Header provides connectionless data integrity and data origin authentication of IP packets. Further, it can also provide protection against the replay attacks by using the sliding window technique and by discarding the old packets. Authentication Header also gives protection for the IP payload and all the header fields of an IP datagram. AH generally operates on the stop of IP, by using the IP protocol number 51. An AH packet diagram is shown below which describes how an AH packet can be constructed and interpreted: Field meanings: Next header: This field is an 8-bit field that mainly identifies the type of the next payload obtained after the Authentication Header. The value of this field can be chosen from the set of defined IP Protocol Numbers. RESERVED These fields are usually reserved for the future use. Payload length This defines the size of Authentication Header packet. Sequence number This field represents a monotonically increasing number which is used to prevent certain replay attacks. Security parameters index (SPI) This field is used to identify the security parameters, in combination with the IP address, and then identify the security association techniques implemented with this packet. Authentication data This field contains the integrity check value (ICV) which is necessary to authenticate the packet. This field may also contain padding. Encapsulating Security Payload: ESP which can be expanded as Encapsulating Security Payload is a member belonging of the IPSec protocol suite. IPSec achieves integrity, origin authenticity, and confidentiality protection of packets. This protocol also supports encryption-only and authentication-only configurations. However usage of only encryption technique without authentication is not recommended because it is termed insecure. ESP does not protect the IP packet header like the Authentication Header (AH) does. The packet diagram below shows how an ESP packet is constructed and interpreted: Field meanings: Security paramete Network System for Secure Communication Network System for Secure Communication Methodology: The main methodology involved behind this research project is to provide the importance of such technology from professionals and well referred articles. Some of the general interviews will be added to the project with details showing their interest towards the current technology and also the change they see in communicating with the new technology. It on the hands of the components of IP Security that contribute to this level of secure communication: The IP Security (IPSec) Driver is used to monitor, filter, and secures the traffic throughout the system. The (ISAKMP/Oakley) abbreviated as Internet Security Association Key Management Protocol performs key exchange and management functions that oversee security issues between hosts, and provide keys which can be used with security algorithms. The IP Security Policy and the Security Associations are derived from those policies that define the security environment where two hosts can communicate. The function of Security Association API is to provide the interface between the IPSec driver, the Policy Agent and the ISAKMP. The function of the management tools is to create policies, monitor IP Security statistics, and log IP Security events. The main methodologies which are under consideration for this project are Classical encryption technologies, IP sec Tunnel, IP sec VPN, Internet Key Exchange methods, Block Cipher Data Encryption, Advanced Encryption, Symmetric ciphers, Public private key functions, Digital signature etc, which have suggested me to design a better system. Implementation: The main reason behind selecting IPSec is that it so powerful that it provides security to IP layer, and also forms the basis for all the other TCP/IP protocols. This is generally composed of two protocols: Authentication Header (AH); Encapsulating Security Payload (ESP); IPSec Implementation Methods: IPSec is comprised of several implementations architectures which are defined in RFC 2401. The IPSec implementation also depends on various factors including the version of IP used (v4 versus v6), the basic requirements of the application and other factors. End Host Implementation: Implementing IPSec in all host devices provides the most flexibility and security. It enables â€Å"end-to-end† security between any two devices on the network. Router Implementation: Router implementation however is a much simpler task since we only make changes to a few routers instead of hundreds or thousands of clients. It only provides protection between pairs of routers that implement IPSec, but this may be sufficient for certain applications such as virtual private networks (VPNs). The idea will be implemented after proper testing of various available methodologies. The current strategy for implementation is as follows:. We use certain open source softwares which provide encryption and decryption methods and authentication. In the actual system, the user is asked to enter details of files to be sent and also some other details about the password and the public keys if included. The required software are used in a way which helps to run a smooth process and secure operation. CONTENTS Acknowledgement I owe many thanks to people who helped supported me in doing my dissertation. Firstly, I would like to express my immense gratitude to my respected professor Mr. Dr. XXX, YYYY University, London for his support and motivation that has helped me to come up with this project. He supported me when its needed and suggested me in understanding various methodologies in my project. He also took care of my project with attention to achieve my goal. I thank to my Institution and faculty members for giving me an opportunity to do my dissertation and also for library, computer lab facilities for doing my dissertation to achieve practical results which can resolve my project related issues. I also extend my Heart full thanks to my family friends. I owe my special thanks to my Dad and his colleagues who gave me suggestions on doing my Dissertation. Abstract In the present system the network helps a particular organization to share the data by using external devices. The external devices are used to carry the data. The existing system cannot provide security, which allows an unauthorized user to access the secret files. It also cannot share a single costly printer. Many interrupts may occur within the system. Though it is advantageous we have numerous disadvantageous, somebody writes a program and can make the costly printer to misprint the data. Similarly some unauthorized user may get access over the network and may perform any illegal functions like deleting some of the sensitive information Security is the term that comes into picture when some important or sensitive information must be protected from an unauthorized access. Hence there must be some way to protect the data from them and even if he hacks the information because he should not be able to understand whats the actual information in the file, which is the main intention of the project. The project is designed to protect the sensitive information while it is in transaction in the network. There are many chances that an unauthorized person can have an access over the network in some way and can access this sensitive information. My main topic focuses on IPSec (Internet Protocol Security) is an extension to the IP protocol specified by IETF which provides security to the IP and the upper-layer protocols and cryptography in a network sharing system. It was first developed for the new IPv6 standard and then â€Å"back ported† to IPv4. The IPSec architecture is described in the IPSec uses two different protocols AH (Authentication Header) and ESP (Encapsulating security payload) to ensure the authentication, integrity and confidentiality of the communication. It uses strong cryptography to provide both authentication and encryption services. Authentication ensures that packets are from the right sender and have not been altered in transit. Encryption prevents unauthorised reading of packet contents. [2] Cryptography is the technique used to secure the data while they are in transactions. Encryption and Decryption are two techniques used under cryptography technology. Data cryptography is the art of securing the resource that is shared among the applications. The main idea behind the design is to provide a secured communication between the networks showing network level performance practically by differentiating different operating system which can ensure the security, authenticity by considering, analyzing and testing any best available methodologies. 1. Introduction: Businesses today are focused on the importance of securing customer and business data. Increasing regulatory requirements are driving need for security of data. There have been many methods which have evolved over the years to address the need for security. Many of the methods are focused at the higher layers of the OSI protocol stack, thus compensating the IPs lack in resolving security issues. These solutions can be implemented in certain situations, but they cannot be generalized because they are particularly too many applications. For example, Secure Sockets Layer (SSL) can be used for certain applications like World Wide Web access or FTP, but there are many other applications which cannot be resolved with this type of security. A solution is required to allow security at the IP level was very necessary so that all higher-layer protocols in TCP/IP could take advantage of it. When the decision was made to develop a new version of IP (IPv6), this was the golden opportunity to resolve not just the addressing problems in the older IPv4, but also resolve lack of security issues as well. Later a new security technology was developed with IPv6 in mind, but since IPv6 has taken long time to develop, and thus a solution was designed to be usable for both IPv4 and IPv6. The technology which brings a secure communications to the Internet Protocol is known as IP Security, commonly abbreviated as IPSec. IPSec services allow users to build secure tunnels through certain networks. All the data that passes through the entrusted net is encrypted by the IPSEC gateway machine and decrypted by the gateway at the other end. The result obtained is a Virtual Private Network or VPN. This network is effectively private even though it includes machines at several different sites which are connected by the insecure Internet. Cryptography technique is used to secure the data while they are in transactions. Encryption and Decryption are two techniques which are used under cryptography technology. Data cryptography is the art of securing the resource that is shared among the applications. The Encryption and Decryption are termed as two powerful security technologies that are widely implemented to protect the data from loss and deliberate compromise. In this project the networking allows the company to share files or data without using certain external devices. Some unauthorized users may get access over the network and perform some illegal functions in certain cases like deleting files while the transaction is still on at that time encryption and then decryption techniques are implemented to secure the data. Many other attacks in cryptography are considered which lead me to research on different types of IPSec implementation methodologies in order to design the best model such that it may be suitable for the present trend of networking systems also form a platform to enable communication to the outside world. Thus in orders to implement IPSec, certain modifications are required to the systems communications routines and certain new systems processes conduct secret key negotiations. What is IPSec? An extension to the IP protocol is considered as IPSec which provides high level security to the IP and to the upper-layer protocols. This was initially developed for the new IPv6 standard and then was back ported to IPv4. IPSec provides the following security services: data origin authentication, connectionless integrity, replay protection, data confidentiality, limited traffic flow confidentiality, and key negotiation and management. It has been made mandatory by the IETF for the use of IPSec wherever feasible; the standards documents are close to completion, and there are numerous implementations. Overview of IPSec Architecture: The IPSec suite defined as a framework of open standards. The following protocols are used by IPSec to perform various functions. [2][3] IPSec provides three main facilities which are explained below: Internet key exchange(IKE and IKEv2) : This is used to set up a security association (SA) which can be done by handling negotiation of protocols and algorithms and generating the encryption and authentication keys which can be used by IPSec.[4][5] Authentication Header (AH): This is used to provide connectionless integrity and data origin authentication for IP datagrams and also provides protection against replay attacks.[6][7] Encapsulating Security Payload (ESP): This is used to provide confidentiality, data origin authentication, connectionless integrity, anti-replay service, and limited traffic flow confidentiality. [9] Both authentication and encryption are generally desired in this mechanism. Assure that unauthorized users do not penetrate the virtual private network Assure that eavesdroppers on the Internet cannot read messages sent over the virtual private network. Since both the above features are generally desirable, most implementations are likely to use ESP rather than AH. Security Association: The security Association mechanism is used for authentication (AH) and confidentiality (ESP) A one way relationship between a sender and a receiver that affords security services to the traffic carried on it. Security services are afforded to an SA for the use of AH or ESP but not both. SA identified by three parameters: Security Parameter Index (SPI) IP destination address Security protocol identifier Overview of IPSec Services and Functions: IPSec is not only assumed as a single protocol, but is rather considered as a set of services and protocols which provide a complete security solution to the IP network. These services and protocols are combined to provide various types of protection. Since IPSec usually works at the IP layer, it provides protection for any higher layer TCP/IP application or protocol without using any additional security methods, which is considered as a major strength for its implementation. General types of protection services offered by IPSec include: Encryption of user data to achieve privacy. Authentication and message integrity has to be achieved to ensure that it is not changed on route. Protection against certain types of security attacks, such as replay attacks. The ability of the devices to negotiate the security algorithms and keys required in order to meet their security needs. wo security modes called tunnel and transport are implemented to meet the various network needs. Features Benefits: IPSec is observed to be transparent by the end users. The users on the security mechanisms need not be trained. IPSec assures security measures for individuals. There is no requirement to change the software on a user or a server system. Strong security measures are applied to the entire traffic crossing the perimeter. 2. Objective: IPSec is mostly designed in order to encrypt the data between the two systems without any spoofing attacks. It is a key force of defence against internal and external attacks. However, other than these, there are many other security strategies which have prevented the security attacks. The main idea in my research is to provide a better approach to the implementation of IP Security by analyzing the present methodologies. In the implementation of this design, I am also considering different operating systems to provide a better approach towards security which can prove to be good in ideal ways. The design of such an approach is helpful in restricting any unauthorised access to the network and also helps in providing a secure and authenticated access. The main idea behind the design is to provide a secured communication between the networks independent of the operating system which can ensure the security, authenticity by considering, analyzing and testing any two best available methodologies. In my overview of RFCs available in the Internet such as Cryptography the receiver end of a particular communication channel is not aware of the sender unless the sender transmits some information with private and public keys with cipher text which can prove his authenticity. Now the receiver sends the same package with his signature and then the receiver is also authenticated mutually. Attacks may occur in different ways. There are also many ways where in such communications can be detected and using techniques like eavesdropping or sniffing or man in the middle attack. These are the three major problems for secure communications. In my research, I will attempt to design a procedure which can be easily followed in order to overcome such problems. There are many techniques available now which are better than normal communication. The major problem in such techniques is the implementation of man in the middle attack. There have been many advances to try and rectify the problems but there has always been a flaw in the design. My research is to design a system using the current technologies used to encrypt and authenticate. These techniques play a major role in the implementation of IP Security. The major interest would be in areas like encryption, decryption and authentication. Additions will be done to this research as it is implemented. The goal is to use research existing systems and to suggest a system which makes it even hard to break. It is not 100% immune to attacks but the attack may take longer to break the system than the present rate. This system will also be very safe and will be easy to use in daily life rather than something with a dozen processing steps to be followed. 2.2 SCOPE With the rapid development of Multimedia data management technologies over the internet there is need to concern about the internet there is need to concern about the security and privacy of information. In multimedia document, dissipation and sharing of data is becoming a common practice for internet based application and enterprises. As the internet forms the open source the present for all users security Forms the critical issue. Hence the transfer of information over the internet forms the critical issue. At the present situations the cryptographic techniques are used for providing ‘SECURITY. 2.3 PROJECT PERSPECTIVE The project â€Å"Network system for Secure Communication† is totally enhanced with the features that enable us to feel the real-time environment. Todays world is mostly employing the latest networking techniques instead of using stand-alone PCs. IPSec tunnelling or Encryption, information scrambling technology is an important security tool. By properly applying, it can provide a secure communication channel even when the underlying system and network infrastructure is not secure. This is particularly important when data passes through the shared systems or network segments where multiple people may have access to the information. In these situations, sensitive data and especially passwords should be encrypted in order to protect it from unintended disclosure or modification. 2.4 PROPOSED SYSTEM In this system ‘security is the term that comes into picture when some important or sensitive information must be protected from an unauthorized access. Hence there must be some way to protect the data from them and even if he hacks the information, The proposed system provides the ‘security and it does not allow unauthorized users to access the secret files. As per the ISO standards the security parameters are: Confidentiality Authentication Integrity Key distribution Access control CONFIDENTIALITY: Confidentiality is the protection of transmitted data from passive attacks. It can protect the data from unauthorized disclosure. AUTHENTICATION: A process used to verify the integrity of the transmitted data, especially a message. It is the process of proving ones identity to someone else. INTEGRITY: The sender and the receiver want to ensure that the content of their communication is not altered during transmission. KEY DISTRIBUTION: Key distribution can be defined as a term that refers to means of delivering a key to the communicating parties, without allowing others to see the key. ACCESS CONTROL: It is a ability to limit and control the access to host systems and applications via communication links. 3.Literature Review This project emphasis design and evaluates a computer-based system using appropriate process and tools. Most of the industry wide routers in the network implement their functionality in hardware and therefore we believe that hardware based routers are more efficient than a software-based router implementation besides that most of the work is in the research community which will be performed, using software-based routers utilizing off-the-shelf PCs. Various works have to be attempted which evaluates different protocol stack, however none of them use hardware-based routers, has such a wide range of metrics, and none investigated mechanisms. My research methodology emphasis surveys, forums from the internet and articles from IEEE (Institute of Electrical and Electronics EngineersorIEEE) a quantitative approach in advance technology. I also consider various other thesis and books which are best suitable for my project. Here following are the network related definitions, and few protocols from application layer, network and internet layer also discussed which actually gives clear idea of understanding the concepts. 3.1 IPSec Standards: IPSec is actually a collection of techniques and protocols; it is not defined in a single Internet standard. Instead, a collection of RFCs defines the architecture, services and specific protocols used in IPSec. Some of the most important of these are shown below: [RFC 2401] Security Architecture for the Internet Protocol (IPSec overview) The main IPSec document describes the architecture and general operation of the technology, and showing how the different components fit together. [RFC 2402] IP Authentication Header It defines the IPSec Authentication Header (AH) protocol used for ensuring data integrity and origin verification. [RFC 2403] The Use of HMAC-MD5-96 within ESP and AH Describes a particular encryption algorithm for use by AH and ESP called Message Digest 5 (MD5), HMAC variant. [RFC 2404] The Use of HMAC-SHA-1-96 within ESP and AH Describes a particular encryption algorithm for use by AH and ESP called Secure Hash Algorithm 1 (SHA-1), HMAC variant. [RFC 2406] IP Encapsulating and Security payload (ESP) It describes the IPSec Encapsulation Security Payload (ESP) protocol that provides data encryption for confidentiality. [RFC 2408] Internet Security Association and Key Management Protocol (ISAKMP) It defines methods for exchanging keys and negotiating security associations. [RFC 2409] The Internet Key Exchange (IKE) Describes the Internet Key Exchange (IKE) protocol used to negotiate security associations and exchange keys between devices for secure communications. It is based on ISAKMP and OAKLEY. [RFC 2412] The OAKLEY Key Determination Protocol It describes a generic protocol for key exchange. [RFC 2131] Dynamic Host Configuration Protocol (DHCP) DHCP allows a host to obtain an IP address automatically, as well as to learn additional information about subnet mask, the address of its first-hop router, and the address of its local DNS server. [RFC 2131; RFC 3022] Network Address Translation (NAT)- In an attempt to provide transparent routing to hosts, NAT devices are used to connect an isolated address realm with private unregistered addresses to an external realm with globally unique registered addresses. Domain Name System (DNS): It is a hierarchical naming system for computers, services, or any resource connected to the Internet or a private network. It associates various other information with domain names assigned to each of the participants. Most importantly, it translates domain names meaningful to humans into the numerical (binary) identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide. For example, www.example.com translates to 208.77.188.166. Windows Internet Name Service (WINS): It is Microsofts implementation of NetBIOS Name Service (NBNS), a name server and service for NetBIOS computer names. Effectively WINS is to NetBIOS names, like DNS is to domain names in fact its a central mapping of host names to network addresses. Like DNS it is broken into two parts, a Server Service (that manages the encoded Jet Database, server to server replication, service requests, and conflicts) and a TCP/IP Client component which manages the clients registration and renewal of names, and takes care of queries. VPN (Virtual Private Network) : It is a virtual computer network that exists over the top of an existing network. The purpose of a VPN is to allow communications between systems connected to the VPN using an existing shared network infrastructure as the transport, without the VPN network being aware of the existence of the underlying network backbone or without the VPN interfering with other network traffic on the backbone. A VPN between two networks is often referred to as a VPN Tunnel. Most VPN technologies can be separated into two broad categories, Secure VPNs and Trusted VPNs. Internet Protocol version 6 (IPv6): It is the next-generation Internet Protocol version designated as the successor to IPv4. It is an Internet Layer protocol for packet-switched internetworks. The main driving force for the redesign of Internet Protocol was the foreseeable IPv4 address exhaustion. IPv6 was defined in December 1998 by the Internet Engineering Task Force (IETF) with the publication of an Internet standard specification, RFC 2460. IPv6 has a vastly larger address space than IPv4. This results from the use of a 128-bit address, whereas IPv4 uses only 32 bits. This expansion provides flexibility in allocating addresses and routing traffic and eliminates the primary need for network address translation (NAT), which gained widespread deployment as an effort to alleviate IPv4 address exhaustion. Due to its security and flexibility entire Internet will be deployed byIPv6 in 2012 as expected. Tunnelling: In computer networks tunnelling protocol (delivery protocol) encapsulates the different payload protocol i.e., It carries a payload over an incompatible delivery-network. It can also provide a secure path through an untrusted network without any data loss. Transport Layer Security (TLS): Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide security for communications over networks such as the Internet. TLS and SSL encrypt the segments of network connections at the Transport Layer end-to-end. Encryption: In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information (in cryptography, referred to as cipher text). In many contexts, the word encryption also implicitly refers to the reverse process, decryption. Internet Key Exchange: Internet Key Exchange (IKE or IKEv2) is the protocol used to set up a security association (SA) in the IPSec protocol suite. IKE uses a Diffie-Hellman key exchange to set up a shared session secret, from which cryptographic keys are derived. Public key techniques or, alternatively, a pre-shared key, are used to mutually authenticate the communicating parties. 4.IPSec System Architecture Authentication Header and Encapsulating Security Payload are commonly called â€Å"protocols†, though this is another case where the validity of this term is debatable. They are not really distinct protocols but are implemented as headers that are inserted into IP datagrams, as we will see. They thus do the â€Å"grunt work† of IPSec, and can be used together to provide both authentication and privacy. IPSec protocols: The IPSec protocol family consists of two protocols: Authentication Header (AH) and Encapsulated Security Payload (ESP). Both these protocols are independent IP. AH is the IP protocol 51 and ESP is the IP protocol 50 Authentication Header: This is a member of the IPSec protocol suite. Authentication Header provides connectionless data integrity and data origin authentication of IP packets. Further, it can also provide protection against the replay attacks by using the sliding window technique and by discarding the old packets. Authentication Header also gives protection for the IP payload and all the header fields of an IP datagram. AH generally operates on the stop of IP, by using the IP protocol number 51. An AH packet diagram is shown below which describes how an AH packet can be constructed and interpreted: Field meanings: Next header: This field is an 8-bit field that mainly identifies the type of the next payload obtained after the Authentication Header. The value of this field can be chosen from the set of defined IP Protocol Numbers. RESERVED These fields are usually reserved for the future use. Payload length This defines the size of Authentication Header packet. Sequence number This field represents a monotonically increasing number which is used to prevent certain replay attacks. Security parameters index (SPI) This field is used to identify the security parameters, in combination with the IP address, and then identify the security association techniques implemented with this packet. Authentication data This field contains the integrity check value (ICV) which is necessary to authenticate the packet. This field may also contain padding. Encapsulating Security Payload: ESP which can be expanded as Encapsulating Security Payload is a member belonging of the IPSec protocol suite. IPSec achieves integrity, origin authenticity, and confidentiality protection of packets. This protocol also supports encryption-only and authentication-only configurations. However usage of only encryption technique without authentication is not recommended because it is termed insecure. ESP does not protect the IP packet header like the Authentication Header (AH) does. The packet diagram below shows how an ESP packet is constructed and interpreted: Field meanings: Security paramete

The Scientific Revolution Essay -- essays research papers

During the Scientific Revolution scientists such as Galileo, Copernicus, Descartes and Bacon wrestled with questions about God, human aptitude, and the possibilities of understanding the world. Eventually, the implications of the new scientific findings began to affect the way people thought and behaved throughout Europe. Society began to question the authority of traditional knowledge about the universe. This in turn, allowed them to question traditional views of the state and social order. No longer was the world constructed as the somewhat simple Ptolemaic Model suggested. The Earth for the first time became explicable and was no longer the center of the universe. Many beliefs that had been held for hundreds of years now proved to be false. In addition to this, the Roman Catholic Church, which had always clarified the movements of the universe with the divine power of God, was now questioned by many. The Roman Catholic Church was naturally set as an opponent of the Scientific Revo lution, not so much because of opposition to new ideas but instead because the new information contradicted the model of the world the church had created. Fortunately the revolution did not happen overnight but moderately over a 150-year period. Nicolaus Copernicus was one of the first astronomers to question the single worldview that the Christian faith supported. Though it was in the later years of his life that the he published On the Revolutions of Heavenly Spheres, the question was now raised as to the correctness of the mechanics of the world. In his writings, Copernicus was not able to accurately describe the revolutions of the Earth, Sun and Stars, but he was the first man to use mathematics and observation in order to create a more accurate picture of the universe. However, in order to conform to the Roman Catholic Church, Copernicus expressed himself carefully. Copernicus states,   Ã‚  Ã‚  Ã‚  Ã‚  I may well presume, most Holy Father, that certain people,   Ã‚  Ã‚  Ã‚  Ã‚  as soon as they hear that in this book about the Revolutions   Ã‚  Ã‚  Ã‚  Ã‚  of the Spheres of the Universe I ascribe movement to the earthly   Ã‚  Ã‚  Ã‚  Ã‚  globe, will cry out that, holding such views, I should at once be   Ã‚  Ã‚  Ã‚  Ã‚  hissed off the stage†¦ (Aspects of Western Civilization 41) Through this statement, Cop... ...leo had attempted to complete. With his information the model of the universe had been at last completed. The Bible and God were no longer needed to explain the mysterious connection of the planets and stars. Newton did not receive the same resistance from the church perhaps because his finding where towards the end of the Scientific Revolution. The Roman Catholic Church could no longer refute the finding of science and submitted. The advances in science over the 150-year period served to crush superstitions and magical believes that people had fathomed to explain the world. Copernicus began the revolution with his finding on the Earth, planets and stars. Galileo went further to connect the world. This came to him at great cost. Bacon and Newton meet less resistance from the Church, possibly due to their approach. In the end science proved to have the final say in the matter, not so much as to discredit the church but rather to dictate there place in the world of science. Religion is based on faith; it always has been, during the Scientific Revolution the church had extended their grip into science. In the end they remain separate, leaving each individual to decide on their own.

Cohesion for Writing Projects Essay

Cohesion, or coherence, is the intangible glue that holds paragraphs together. Having good coherence in a writing project means that your ideas stick together and flow smoothly from one sentence to the next, so that readers of your work can easily understand where you are taking them. Without cohesion, a written work can seem choppy and may not flow well; a lack of coherence challenges the reader and can hurt comprehension, thus rendering your attempt at communication ineffective at best. We will look at cohesion within paragraphs, but the basics below, along with organizational devices like headings, help to link sentences, paragraphs and sections coherently in longer, complex writing projects. Here are four main components of cohesion: relevance order linking words repetition of key words 1. RELEVANCE A simple way to build cohesion or flow between sentences is to look at the meaning of a sentence and compare it to the point of the next sentence. They should be related yet not the same. If the two sentences are not closely related, you will lose the readers‟ attention, because they will have to guess where you are going. If the two sentences are identical, you are not adding any new information to your work, and the reader will be annoyed. Example – Too different: relevance not clear Antigone‟s motivation is family duty, even if it means death. She must rebel which will cause an uproar – the consequences don‟t matter to her. This would also explain why she rejects Ismene‟s support later in the play. They both have different motivations – Ismene has nothing left to lose and wants to go out with a glorious bang. In this paragraph, two sentences are far too separate. The first two sentences talk about Antigone‟s motivations and how far they will drive her. The focus is then redirected to Ismene, and the paragraph focus is not clear. It lacks cohesion. When a sentence relates the Ismene information back to Antigone, we have cohesion: Antigone‟s motivation is family duty, even if it means death. She wants to rebel which will cause an uproar – the consequences don‟t matter to her. In  contrast, her sister, Ismene, has completely different motivations for her actions and wants glory, which explains why Antigone rejects her support later in the play. Example – Too similar Aristophanes exaggerates Socrates‟ intelligence in a humorous way. Aristophanes portrays Socrates‟ intelligence as a tool of humor. He makes Socrates use his intelligence to make a mockery of people. Aristophanes makes Socrates appear very brash in the use of his intelligence. The author conveys only two points with these four sentences – that Aristophanes uses Socrates‟ intelligence as a joke, and that he did so by having Socrates mock people. Cutting away the unnecessary repetitions strengthens cohesion: Aristophanes exaggerates Socrates‟ intelligence in a humorous way. The playwright makes Socrates use his intelligence to make a mockery of people, being very brash in the process. 2. ORDER Writers should always ask themselves â€Å"Is this sentence relevant to the idea of this paragraph?† Every paragraph should have a main idea (typically stated in a topic sentence). To maintain cohesion, all sentences within a paragraph should relate to this main idea. For example, if you are writing a paragraph on why nuclear power plants are an efficient, clean way of generating energy, it may seem out of place to then reflect on why a duck‟s quack does not echo and the resulting societal implications. More often than  not, these sentences are important to your paper, but need to be moved elsewhere: in a separate paragraph or just relocated within the same paragraph so the sentences order is logical. Common ways to order sentences Chronological Cause and Effect Clarification (first sentence is broad, general statement, and the following sentences explain it with details) Compare/Contrast Example – Chronology is unclear Then there was another meeting with Satan, who said if Job‟s body was tested Job would sin against God. The three friends Eliphaz of Teman, Zophar of Naamah, and Bildad the Shuah came to try and console Job. The three saw then that Job was stricken with disease and his  suffering was very great. Chronological order and time signals improve cohesiveness: There was another meeting with Satan, who said if Job‟s body was tested Job would then sin against God. When Job was later stricken with disease and suffering greatly, his three friends, Eliphaz of Teman, Zophar of Naamah and Bildad the Shuah, tried to console him. Example – Cause and effect: These sentences start with an action that is the result of an earlier event. Flow is not smooth because without links or logic, the reader has to do a little bit of mental rearranging: The detective tried to gather more evidence by going to the store to ask Mr. McDougal what he knew about the murder. He did this because when he had asked the Davidson‟s maid what she saw at the scene of the crime, she mentioned McDougal. Ordering these sentences by cause and effect, i.e. chronologically, creates: The detective talked to the Davidson‟s maid and asked her what she saw at the scene of the crime. She mentioned the local store owner, Mr. McDougal, so the detective then visited McDougal to gather more evidence. 3. LINKING/TRANSITION WORDS Transition words can help a paragraph flow more smoothly. The following two sentences are far apart, in fact, opposites in content and unconnected in time. Example: As one can see, early in the history of the United States, most pollution was created without regard to the environment. Different private groups have taken steps towards preserving nature, including conservationists and environmentalists. A transition word, â€Å"however,† announces the contrasting relationship for the reader, avoiding the stop and start rollercoaster effect and creating cohesion. â€Å"Today† moves the reader from â€Å"early history.† As one can see, early in the history of the United States, most pollution was created without regard to the environment. However, different private groups today have taken steps towards preserving  nature, including conservationists and environmentalists. For cohesion within and between paragraphs – The transition words and phrases below are an abbreviated list of transition terms found at: http://www.studygs.net/wrtstr6.htm. Find more help at http://larae.net/write/transition.html Addition: also, again, besides, furthermore, in addition, likewise, moreover, as well as Result: thus, therefore, as a result, consequently, for this reason, hence, otherwise, subsequently Generalizations: typically, as usual, for the most part, generally, usually, in general Introducing Examples: for example, for instance, as an illustration, as an example, in this case Emphasis: above all, chiefly, especially, particularly, significantly, most importantly, primarily Similarity: comparatively, correspondingly, likewise, similar, together with, combined with Exception: aside from, barring, besides, except, excluding, exclusive of, other than, outside of Restatement: in essence, in other words, namely, that is, in short, to put it differently Contrast /Compare: in contrast, conversely, instead, on the other hand, on the contrary, rather, similarly, yet, but, however, still, nevertheless, in contrast, comparatively, likewise Order (time): at first, to begin with, at the same time, now, the next step, in turn, later on, meanwhile, next, then, soon, later, while, earlier, simultaneously, afterward, before, prior, last, meanwhile Summary: in brief, in conclusion, in short, in summary, in the final analysis, finally 4. REPETITION OF KEY WORDS Repeating key terms related to the main idea of the paragraph makes an invisible rope for readers to follow – a few hand holds. However, do not repeat words for the sake of repetition; the reader needs to occasionally be reminded of your focus, not beaten over the head with unnecessary repetitions. Example: The following paragraph focuses on the negative impact of the recession on restaurants. Follow the key words, variations of â€Å"economy,† â€Å"restaurant,† and â€Å"weak†; they tie sentences together as each negative effect is added to the paragraph: Many problems in the economy are impacting the restaurant industry. The factor responsible for most of these negative impacts is the economic recession. Due to weak economic conditions, the U.S. food service industry revenues will only rise 2.5% in 2008, compared to the 4.6% increase in 2007; the National Restaurant Association reports this to be among the poorest sales performances by the domestic restaurant industry in nearly four decades (Basham, 2008b). In response to the weak economic conditions, restaurants are increasing prices only enough to offset higher costs, rather than to expand profit margins (Basham, 2008b). Also, unemployment in the United States affects restaurants with rates reaching 5.3% in 2008 compared to 4.6% in 2007 (Basham, 2008b). The government has also made cost difficult for restaurants by increasing the federal minimum wage to $7.25 in 2009 (Basham, 2008b). Finally, consumers are traveling less which is lowering restaurant  sales; travelers and visitors accounted for a median of 15% of sales at quick service restaurants. At this time, the weak economic conditions have had a major impact on the food service industry. Repetition of the blue key words links the negative impacts on revenues, prices, employment, labor costs and customer traffic in the restaurant industry. Note also the transition words and phrases: â€Å"due to,‟ „in response,‟ â€Å"also,† â€Å"finally.† To avoid needless repetition: As you read each sentence, you naturally expect the next sentence to relate directly to the previous sentence. And this sentence does relate because I am still talking about your, the reader‟s, expectation. But what happens if I don‟t follow-up on the preceding one? I would break your reader attention. In a cohesive paragraph, every sentence builds on the information in the previous sentence, so that you avoid creating a bumpy wooden roller-coaster ride for your reader. If the subjects of two sentences are the same, typically a pronoun can be used to refer to the subject. Example: As you Like It was a universal play that, when set in modern times, still makes sense and can capture an audience. The play As you Like It uses modern costumes, props, and interactions with the audience to relate the story to our times. Note how the repetition of the full name of the play makes the beginning of the second sentence awkward. With a pronoun, it reads As you Like It was a universal play that, when set in modern times, still makes sense and can capture an audience. It uses modern costumes, props, and interactions with the audience to relate the story to our times. Warning: Be sure the reader will know what â€Å"it,† â€Å"he,† â€Å"that,† and other pronouns mean. See http://www.clarkson.edu/writingcenter/docs/vague_pronouns.pdf Finally†¦ 5. REREAD & REVISE! The best way to improve cohesion is to thoroughly reread your paragraphs. Many times, writers quickly put down all of their thoughts in a stream of  consciousness. While everything that they write makes sense at the time, it may seem like a garbled mess to a reader. Rereading your work (or having a friend, professor or tutor read it) allows you to add any missing links, fill gaps in logic and create cohesion. Additional Resources: http://www.ecu.edu/first_year_studio/workshops/printable_ws/Organization_and_Cohesion.doc http://leo.stcloudstate.edu/style/cohesion.html http://papyr.com/hypertextbooks/comp1/coherent.htm http://owl.english.purdue.edu/owl/resource/561/04/ http://leo.stcloudstate.edu/style/transitioncues.html

Lewis Structure Example Problem - Formaldehyde

Lewis Structure Example Problem - Formaldehyde Lewis dot structures are used to predict the geometry of a molecule. You will be able to draw a Lewis structure of the formaldehyde molecule after using this equation. Question Formaldehyde is a toxic organic molecule with molecular formula CH2O. Draw the Lewis structure of formaldehyde. Step 1 Find the total number of valence electrons. Carbon has 4 valence electronsHydrogen has 1 valence electronsOxygen has 6 valence electronsTotal valence electrons 1 carbon (4) 2 hydrogen (2 x 1) 1 oxygen (6)Total valence electrons 12 Step 2 Find the number of electrons needed to make the atoms happyCarbon needs 8 valence electronsHydrogen needs 2 valence electronsOxygen needs 8 valence electronsTotal valence electrons to be happy 1 carbon (8) 2 hydrogen (2 x 2) 1 oxygen (8)Total valence electrons to be happy 20 Step 3 Determine the number of bonds in the molecule.number of bonds (Step 2 - Step 1)/2number of bonds (20 - 12)/2number of bonds 8/2number of bonds 4 Step 4​ Choose a central atom.Hydrogen is the least electronegative of the elements, but hydrogen is rarely the central atom in a molecule. The next lowest electronegative atom is carbon.   Step 5: ​ Draw a skeletal structure. Connect the other three atoms to the central carbon atoms. Since there are 4 bonds in the molecule, one of the three atoms will bond with a double bond. Oxygen is the only choice in this case since hydrogen only has one electron to share. Step 6: ​ Place electrons around outside atoms.There are 12 valence atoms total. Eight of these electrons are tied up in bonds. The remaining four complete the octet around the oxygen atom.Each atom in the molecule has a complete outer shell full of electrons. There are no electrons left over and the structure is complete. The finished structure appears in the picture at the beginning of the example.