BAN - A Logic of Authentication Essay Example | Topics and Well Written Essays - 2250 words

BAN - A Logic of Authentication - Essay Example As a result, Borrows, Abadi and Needham formulated a logic of belief and action, to address these errors. The logic allows people to formally describe the beliefs of trustworthy parties involved in these authentication protocols, thus uncovering subtleties, redundancies and flaws through an analysis of the protocols’ syntax and semantics. Borrows, Abadi and Needham take four published protocols into account, in order to show how they illustrate the appropriateness of this logical method of analysis. But how sound is the logic that they are proposing? How far can a vague and ambiguous logic take us? This paper aims to introduce the famous BAN (Borrows, Abadi and Needham) logic and it’s use on one of the published protocols (i.e. Kerberos), to discuss the logic’s success, its successors, and to review the critiques made on the logic. This paper is based on the article †A Logic of Authentication† published in 1989 by the authors Michael Burrows, Martin A badi and Roger Needham, University of Cambridge. The paper was nominated for publication in TOCS by the Program Committee for the ACM SIGOPS Symposium on Operating Systems Principles, December 1989. The three authors completed part of this work at Digital Equipment Corporation and part at the University of Cambridge. 2 Chapter 2 Introduction In this chapter a brief introduction to the basic principles of the BAN logic is discussed as well as a short section about security protocols. 2.1 An Introduction to Borrows, Abadi, Need- ham (BAN) Logic The BAN Logic is named after Borrows, Abadi and Needham. The logic is, as they stated, a logic of belief and action. It contains no logical inversions; therefore it cannot be used to prove that a protocol is flawed. But when proof, that a protocol is correct, cannot be obtained, that protocol deserves to be treated with suspicion [?]. In other words BAN logic does not aim to prove the security of a protocol; it can only catch certain kinds of s ubtle errors, help us to reason about the protocol, and help us identify and formalize our assumptions and analysis. Details of the BAN logic such as the idealization of protocol transactions, along with the various inference rules, will be discussed on the later sections. The authors of †A Logic of Authentication† introduce the BAN logic to protocol designers whom they believe are inappropriately copying available techniques; thus coming up with protocols containing many security flows. The authors explain the basic notation of the logic and five rules that are applied to analyze protocols. Afterwards, they move on to actually idealize different existing protocols to conclude that such a simple logic can capture subtle differences between protocols. If there is one thing that the authors forgot to mention, that would be the basic definitions of frequently used terms. So in this paper I will try my best to define those terms. 3 CHAPTER 2. INTRODUCTION 4 2.1.1 Security Pr otocols A security protocol usually uses cryptography to distribute messages, authenticate the communicating parties and protects data over an insecure network. It can be defined as a set of transactions or traces. Each transaction consists of a series of communication events, some of which are perhaps interleaved protocol runs. Every desirable

Aboriginal People In Canadian History And Culture History Essay

Aboriginal People In Canadian History And Culture History Essay Canada has provided a home for settlers ever since the first inhabitants arrived on the continent. Each of these groups of settlers had contributed to the rise of the country in several ways. Among the many inhabitants throughout the history of Canada, Canadian Indians had one of the greatest influence on the countrys economy and provided a very rich cultural heritage. Many experts think that the first Indian settlers had migrated to Canada during the last Ice Age, leaving their previous homeland, Siberia. After the ice had melted, only people could cross to Canada through the Bering Strait, while land animals had to stay behind.  [1]  Therefore, Canadian Indians had to establish their villages and society without the help of the most common European domestic animals such as donkeys, horses or oxen. Despite the fact that their domestic animal resources were limited, early Canadian Indians were very successful farmers. During the period between 500 BC and 1000 AD, each of the numerous Indian tribes had their own developed culture, customs and beliefs. Their food sources varied according to the geographical features of their living areas. In the northern areas of the country, fishing and hunting were the most popular means of acquiring food. The tribes living there, for example the Inuits, hunted for whales, thus they introduced a sea-hunting culture to the area. Moreover, among the Inuits, there were several fishermen who fished for salmon in the cold rivers surrounding their villages. The weather around the Arctic was quite harsh, especially during winter when the seas froze and snow covered everything, which made it necessary for the Inuits to develop new objects, such as the dog sleds, or the snow houses  [2]  , which are in use even in present day. The arrival of the European conquerors brought a huge change into the lives of the native people of Canada. As the members of the First Nations were skilled hunters and fishermen, they had resources and useful goods to offer to the Europeans. Among these goods, the most important one was animal fur (first the fur of beavers). Europeans and the native people made contact with each other with the help of trading goods. Europeans traded metal tools (which were very much needed by the Indians) for highly expensive animal fur. The limited cultural background of the North American hunting peoples provided an insatiable demand for the products of the more elaborate cultural development of Europeans. The supply of European goods, the product of a more advanced and specialized technology, enabled the Indians to gain a livelihood more easily to obtain their supply of food, as in the case of moose, more quickly, and to hunt the beaver more effectively.  [3]   As a result, several trading posts had been set up, which later evolved into towns, thus helping the development of Canadian settlements. The most active fur trading tribes, such as the Algonquians and the Hurons had an enermous role in the establishment of the very first trading stations and colonies. They hunted for food which they provided for the colonists, even if they had to carry these goods several hundreds of kilometers to be able to sell them. With the help of these tribes, the French colonists managed to establish the colony of Quebec, the first colony of Canada, in 1608. If it had not been for the help of the Algonquian and the Huron tribes, the French may have not been able to hold their stand on the continent. Due to the fact that the aboriginal inhabitants of Canada had been living in the country for a long time, several geographical areas were named by them, and many of these names are still in use in the present day. Actually, the name Canada originates from an Iroquoian word that means village or settlement  [4]  , which was later adopted by French settlers like Jacques Cartier. Other provinces and territories whose official names are aboriginal in origin are Yukon, Saskatchewan, Manitoba, Ontario, Quebec and Nunavut.  [5]  Also, there are thousands of towns or cities with their names originating from aboroginal names, which indicates the huge impact of the aboriginal culture on present day Canada. The art of the indigenous people of Canada also largely contributed to the countrys cultural heritage. The most important art had been created before the European settlers arrived, and these artifacts have very unique characteristics. The most popular artifacts produced in that time were the totem poles, which had animals, such as eagles, bears, ravens or legendary creatures depicted on them. Many of the aboriginal people were skilled sculptors or painters, and after the Europeans arrival some of them started to make art for a commercial purpose. As a result, more and more aboriginal art had reached a wide variety of audience, and the Indian art became more and more popular. The culture of the aboriginal people had a huge effect on the contemporary theatre, too. Many stories featured in plays or dramas were based on aboriginal stories told by Indian storytellers. Each tribe had its own creation story or myth that was told orally to the members of the tribe for hundreds of years, and especially during ceremonial occasions. These stories preserved the spoken language of the tribes, and added them to the cultural heritage of Canada. Today, there are several languages still spoken by indigenous people, and the most widespread ones include Anishinaabe and Cree, with several hundred thousand speakers; also Inuktitut, Nunavut, Nunavik, Nunatsiavut, and Mikmaq.  [6]   One of the most important contribution of the native people to the economy of Canada was the use of the canoe throughout the trading period of the 17th and 18th century. As the European colonists could not navigate the area, they often hired aboriginal guides to help them find their way, and to mediate between trading tribes. The canoe (usually made from birch bark) was the fastest means of transport through the rivers of the country, and due to its design and structure, it could carry a huge amount of goods, such as fur, food, or the metal and iron tools that the native people were given in return. There had been several examples of a single native person carrying goods on his canoe from the eastern part of the country to the west. This journey consisted of several thousand kilometers, and the importance of keeping the trade routes active was recognised both by the colonists and the Indians. The native people of Canada contributed to the military successes first against the British, then later against the United States. During the war between the French colonists and the British, the Iroquis had trained the French soldiers in guerilla warfare, which was a great advantage. New France (the French colony in Canada) also had allies among the Algonquians, and they proved to be a great asset. The French had very close trading (hence military) ties with the Abenakis from Maine, many of whom had sought refuge in Canada and with the Micmacs and Malecites in the Maritimes. France also had loose alliances with the Great Lakes Algonquians: the Ojibwa, Ottawa, Potawatomi, Miami, and Illionis. Moreover, the Canadian fur traders and fort commanders, unlike the land-hungry English settlers, cultivated a friendship of the Algonquians by giving the Indians gifts and presents.  [7]   One of the most important Indian war heros was named Tecumseh, leader of the Shawnee tribe, and a large contributor to the success of the war against the Americans. He was later considered a folk legend, and many Canadians remember him as a hero for the defense he did to their country, even today. Apart from cultural and military contributions, the aboriginal people in Canada invented several of the now everyday items and activities, such as maple syrup, tug of war, lacrosse, the toboggan, snowshoes. Lacrosse is now a very popular sport in Canada, while maple syrup is considered one of Canadas national products. The aboriginal people showed the settlers how to make maple syrup, or itsinzibuckwud, as the Alqonquians called it, which meant drawn from wood. In the early days of colonization, it was the Natives who showed French settlers how to tap the trunk of a tree at the outset of spring, harvest the sap and boil it to evaporate some of the water. This custom quickly became an integral part of colony life and during the 17th and 18th centuries, syrup was a major source of high quality pure sugar. Later, however, they would learn to bore holes in the trees and hang their buckets on home-made spouts.  [8]   In modern day Canada, Quebec produces the largest amount of maple syrup in the world, followed by the United States. In conclusion, the native peoples contribution to the economy and cultural heritage of Canada is very important. Not only did the aboriginals made it possible for the European settlers to establish a country in the continent, but they also introduced them to the typical food and tools of the native people, which made the life of the settlers easier. With the help of fur trade, the early Canadian economy was flourishing, and the alliances between the European settlers and the Indians helped Canada obtaining its independence.

Dealing with Clinical Depression: A Rough Idea :: Biology Essays Research Papers

Dealing with Clinical Depression: A Rough Idea Life is full of ups and downs. Every individual experiences mood changes, which are mere reaction to everyday experiences. The loss of a loved one might produce sadness while graduating from school might elicit happiness. Likewise a sunny day might make you smile while; a gray day in the winter might produce the â€Å"blues.† And yet, these reactions are normal, although by no means experienced by all whose lives are touched by the events. The blues are usually short-lived, hours to a few days in duration. They rarely disrupt ability to work and are rarely seen by outside observers as a marked shift in behavior ((2)). Yet the occasional blues is very different from the persistent â€Å"down,† that people with depression experience. It is estimated that in the United States about 19 million people or one in ten adults experience depression each year. Nearly two-thirds do not get help for the disease and or receive the treatment they need. They might be too embarrassed or ashamed to get help or they may not realize that they are depressed and need help. Others think that depression is just part of life and their feelings of sadness will pass in time. While most people experience depression at some time during their lives, depression that last more than a few weeks requires treatment (2). That is the odd thing about depression. Few of us think twice about going to the hospital to set a broken limb, because we know a health-care professional can help us. It is the same for depression. There is a long-running controversy about the cause of depression, which means no one, knows for sure: some say our personal history or experiences (psychology) cause depression, others say brain chemistry causes depression. Yet others say that depression is caused by genetic predisposition (4). Though all theories are valid and supported by various scientific findings, defining the cause of depression is complicated. Obviously, no two individuals become depressed in the same way. For example, one might become depressed from stress while another person might have a genetic predisposition to the disease. To add to the complication of depression, there are various types of the illness. Furthermore, various combinations and severity of symptoms can cause depression and many people su ffer only some traits associated with depression ((2)). Dealing with Clinical Depression: A Rough Idea :: Biology Essays Research Papers Dealing with Clinical Depression: A Rough Idea Life is full of ups and downs. Every individual experiences mood changes, which are mere reaction to everyday experiences. The loss of a loved one might produce sadness while graduating from school might elicit happiness. Likewise a sunny day might make you smile while; a gray day in the winter might produce the â€Å"blues.† And yet, these reactions are normal, although by no means experienced by all whose lives are touched by the events. The blues are usually short-lived, hours to a few days in duration. They rarely disrupt ability to work and are rarely seen by outside observers as a marked shift in behavior ((2)). Yet the occasional blues is very different from the persistent â€Å"down,† that people with depression experience. It is estimated that in the United States about 19 million people or one in ten adults experience depression each year. Nearly two-thirds do not get help for the disease and or receive the treatment they need. They might be too embarrassed or ashamed to get help or they may not realize that they are depressed and need help. Others think that depression is just part of life and their feelings of sadness will pass in time. While most people experience depression at some time during their lives, depression that last more than a few weeks requires treatment (2). That is the odd thing about depression. Few of us think twice about going to the hospital to set a broken limb, because we know a health-care professional can help us. It is the same for depression. There is a long-running controversy about the cause of depression, which means no one, knows for sure: some say our personal history or experiences (psychology) cause depression, others say brain chemistry causes depression. Yet others say that depression is caused by genetic predisposition (4). Though all theories are valid and supported by various scientific findings, defining the cause of depression is complicated. Obviously, no two individuals become depressed in the same way. For example, one might become depressed from stress while another person might have a genetic predisposition to the disease. To add to the complication of depression, there are various types of the illness. Furthermore, various combinations and severity of symptoms can cause depression and many people su ffer only some traits associated with depression ((2)).

Becoming a Police Officer Essay

Although being a police officer can be stressful, it can also be highly rewarding if public service is important to you. (Kara, 1999) When becoming a Police Officer, you are making a commitment to protect your community even if it means giving your life to do it. Despite what some people may think every police officer does their job they way they do it to make sure that your families are safe every night. Just like any job out there now a days you have to have an education. To be a police officer most places are now requiring a two degree. Going beyond a two year degree usually leaves you the opportunity to progress in your field of choice allowing for more job options. Being a Police Officer means that you have to first meet the requirements set forth by the department with which you are applying, have the unique set of skills to do your job efficiently, and you have to have the willingness to further your education to go further in your career. To be successful as a Police Officer there are some characteristics that you need. Some of these characteristics include having a level head, being able to think quickly on your feet, and have the ability to work well under pressure. You have to be able to work well with little to no supervision. This is a skill you need when working undercover and in the field. It is also important that you have self-confidence, and confidence in your ability to make decisions and take the lead in what could be a risky situation. Leadership skills are also important because the people of the community look to you to be able to solve issues and crime related issues. Having the capabilities to be a leader comes very important in the job as an officer. The whole community depends upon your ability to be a leader in their eyes. It’s highly important to have the ability to stay calm in highly stressful situations. If you are unable to stay calm in high pressure situations and emotional intense situations it will become hard for you to as an officer to function on a daily basis. Having patience (which can be difficult at times) and a good set of morals are also important skills an officer must have. An officer must be able to handle situations with patience and good communication skills. These come very handy while interviewing a suspect or even dealing with issues in the community. Having a good set of morals are important because as an officer of the law you must set the example and follow the laws yourself and not believe that you can get away with everything because you are above the law, because you are not. You are an enforcer of the law, so to enforce the law upon others you must also obey the laws yourself. You also should have a good sense of right and wrong to be able to encourage good behavi or to the public. The basic requirements to be a police officer are usually about the same, because most follow the civil service regulations when hiring officers. These requirements would include: Being a United States citizen, you have to be at least twenty-one years old, have a high school diploma or equivalent education, possess a valid driver’s license, and have no prior convictions. Now these are just the basics, most departments generally have more requirements, for example a lot of departments now require that you have at least an associate’s degree in criminal justice. Before you can begin working in a department as an officer you are generally required to attend a police academy which you must complete and pass to be qualified as a Police Officer. When you go through the police academy you are generally there from twelve to fourteen weeks, while there you must pass a physical fitness and written exam. While at the police academy educational wise, you will learn state ordinances and local laws, working with the public, constitutional laws, accident investigation, incident reporting, civil rights, mental preparation for hostility, and criminal psychology. Like most jobs you can learn all you want about a job but, you learn best by doing. Because police jobs are dangerous jobs they require specific training to succeed in the field. Work experience is done under the supervision of a training officer. The on the job training includes: using firearms, responding to emergencies, controlling traffic, CPR and first-aid, self-defense techniques, apprehension techniques, risk assessment, and role playing. All training is essential to be the best you can be at being an officer. All the training that is endured is important for you to be the person the community needs you to be. There are several opportunities for advancement in law enforcement. The police force ranking is clearly structured and goes as followed: Police constable, sergeant, inspector, chief inspector, superintendent, chief superintendent, assistant chief constable, deputy chief constable, and chief constable. Police constables have to complete a two year probationary period before they can be eligible for higher ranking. When the probationary period is over police constables are then able to apply for specialist units such as the fraud squad, fire arms, drug squad, child protection, criminal investigation department (CID) traffic, mounted branches, dog handlers, and underwater search units. Becoming a police officer is a process; you are tested physically and mentally. Being a police officer is an important job because those people are there for you, your family, and the community. Not only is education a requirement to being a police officer, but furthering that education will open up more opportunities in that field. To be a police officer it takes a number of skills to be the best you can be at your job. References AGCAS. (2012, January). Police officer career development. Retrieved from http://www.prospects.ac.uk/police_officer_career_development.htm Education Portal. (2003). Police officer: Educational requirements for police officers. Retrieved from http://education-portal.com/articles/Police_Officer_Educational_Requirements_for_Police_Officers.html What type of person can succeed in law enforcement. (n.d.). Retrieved from http://www.communitypolicing.org/law-enforcement-success

Characteristics of Just Laws And Views Essay

A just law has a number of widely recognized characteristics. A just law is characterized by the following: –treats all people equally The notion of equality is an important aspect of the law. Although a just law may be providing equality it doesn’t always occur that way. For example, a wealthy person may be able to afford legal representation, but those people who can’t afford legal representation will be disadvantaged and will not have an equal opportunity before the law. –is based on generally held religious or ethical precepts The common law legal system is the product of various historical influences, many of which were the religious and moral viewpoints of different times. In today’s society, ethics and how they coincide with the law are being replaced by the need for the law to protect society as a whole and consider economic interests. –is utilitarian Utilitarianism is the theory which suggests the law aims to ensure the greatest possible happiness for the greatest possible number of people. –stresses consensus and social cohesion above all Democracy helps create legal consensus. Democratic processes provide all citizens within the state with the opportunity to develop or create the law. Democratic processes will generally require a majority or consensus to bring a law into being. Democratic processes are designed to endure the survival and well being of the community through stressing consensus. –allows for general principles to be mitigated in individual cases Mitigation allows for fairness. The law attempts to treat everyone equally; that = everyone in similar situations is taxed the same, everyone who commits the same crime is given the same penalty. However the courts have discretion to reduce the penalty according to the circumstances. — aims to redress inequalities –It leaves people free To the extent that people do not break the law, a just law will leave people free. –It takes into account of limitations in material resources. –It can be invoked without undue delay. A just law should deal with a legal problem or dispute as soon as practicable after that problem or dispute arises. This is because people’s memories fade and so their evidence becomes less reliable as time passes. But this is not always the case, as currently the Australian legal system has lengthy delays and cases take long periods of time to reach the courts. Formal Equality – theory side of the actual practice. Here in theory everyone in Australia is treated equally and given the same opportunities Institutionalized equality- this is the practical side to it. Although it seems everyone in Australia is equal there are people in sub groups in society who are part of a minority and aren’t able to benefit from the opportunities. E.g. of formal equality: Everyone has to right to access the law. Everyone has the right to vote EQUALITY OF OPPORTUNITY-Equal treatment of people in access to employment and services. †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..So everyone has the right to apply for a job. They have equal rights to a safe working environment. (work cover). Everyone has the equal opportunity to access the minimum wage. EQUALITY BEFORE THE LAW-Everyone is treated equally in their dealings with the law. E.g. The rule of law. †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦So everyone has the implied right to legal representation. All Australian citizens are allowed to contest evidence put forward during court (natural justice – cross examination). EQUALITY OF OUTCOMES-A practice whereby the law, policy or precedent aims to ensure that, regardless of educational or socioeconomic background, or inequality of opportunity, the result of certain exercises will be equality†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..so legal aid, if people aren’t able to afford legal representation they are given the opportunity to apply for legal aid. Does formal equality before the law hides institutionalized inequality? This relates most to EQUALITY OF OUTCOMES because this area is where the law has its most flaws. Although everyone might have the same opportunity not everyone is able to understand that system. For example unskilled migrants who come to Australia looking for a better life think Australia has equal everything†¦true but its not equal if you don’t understand it and aren’t familiar with it. For example: if you come from a non – English speaking background to Australia and get into trouble with the law or are being framed or a victim of fraud and exploitation how are you going to access the law and legal representation if you cant speak the language and don’t understand the system. Therefore not an equal opportunity.