Prevention of Mother-to-Child Transmission of HIV Infection Essay

Prevention of Mother-to-Child Transmission of HIV Infection - Essay Example This method of prevention involves education about HIV in the society, safe-sex practices, avoiding sharing of contaminated needles for intravenous drugs. Proper moral behavior is necessary to follow these norms (Kapoor, p.248). 3. Prevention of transmission of HIV infection from infected mothers to their babies by anti-retroviral therapy. This therapy is instituted both to the pregnant mother and also to the baby after delivery. Transmission of infection is also prevented by avoiding breast feeding (Kapoor, p.248). All pregnant women attending antenatal clinics during pregnancy should be counseled about HIV infection. They should be educated about the disease and the modes of transmission. The women should be encouraged to take up HIV test voluntarily. They should be informed about the importance and implications of the test and also the course of management if found positive. Women with high-risk behavior should be advised about window period and repetition of the test after 3-6 months if the HIV test is negative (Kapoor, p.248). Any woman who is found to be HIV positive should be taken into confidentiality and counseled appropriately. She should be motivated, be taught 'positive thinking' and informed that 'HIV is not AIDS'. She should also be warned against transmission of the disease to others and how to prevent it by following simple steps like using condoms. The option of termination or continuation of pregnancy should be left to her, but she must be advised about antiretroviral therapy for the baby if she decides to continue the pregnancy (Kapoor, p.248). Anti-Retroviral Therapy (ARV) Administration of ARV to the HIV positive pregnant mother decreases the risk of MTCT by reducing the viral load in the mother and also by preventing fixing of the virus in the baby (Kapoor, p.248). Monotherapy with zidovudine causes only suboptimal suppression. Hence it is recommended to use optimal combination of anti-retroviral drugs as is used in non-pregnant women (Chen, p.1616). The treatment currently used in the treatment of adults with HIV infection is 'highly active antiretroviral therapy' (HAART) (Chen, p.1616). It consists of a protease inhibitor or a nonnucleoside reverse-transcriptase inhibitor (NNRTI) such as efavirenz and two nucleoside reverse-transcriptase inhibitors (NRTIs). However, this treatment should be instituted only after 10-12 weeks of gestation to prevent teratogenic effects. All infants born to HIV positive mothers and having received ARV should be followed up long-term irrespective of their HIV status (Chen, p.1616). Nevirapine (NVP) for Prevention of MTCT NVP is a NNRTI. It directly binds to the HIV-1 reverse transcriptase, inhibits the synthesis of viral DNA and thus inhibits the viral replication. After a single dose of 200 mg to the mother, it crosses the placenta efficiently. Added to this advantage, it has a long half-life of 40 hours (Kapoor, p.249). In neonates and infants, the dose is 2mg/kg (Kapoor, p.249). The advantage of NVP therapy is that the administration is a simple two-dose regimen to be taken by mouth. Also, it is inexpensive, easier to maintain confidentiality, does not

California natives Essay Example | Topics and Well Written Essays - 750 words

California natives - Essay Example the degradation of the environment (massive clearing of forests, siltation of river systems, loss of wildlife game and draining of marshlands) that adversely affected the natives. The native population of California just a few centuries ago was so diverse that about 500 independent different tribal groups were identified by anthropologists (ibid. 3) in the area. However, the tragedy was that much of this local culture was lost forever with very few items and artifacts left to record their way of life due to the forced assimilation adopted by settlers. As a result, although the native population had risen after 1900, that population had lost much of its ethnic purity with most of natives half-breed (mixed marriages and broken traditions). Linguistic diversity was also lost with many unable to speak their native tongues. This essay tries to look back at those times and examine the effects of two groups of settlers – the Spaniards and the Russians. Each group had a different purpose of going to the area and therefore had a different impact on the lives of the natives. This paper also looks at a specific aspect of native life during that bygone era and gives brief contrast with the Western way of life and the valuable lessons that could have been learned by everyone. The recorded history of California (as viewed from Western eyes) begun with Spanish religious missions together with settlers and soldiers. The missions and the presidios usually were built near other in case of attacks from the coast or from the native Indians and later on grew into pueblos (small towns). The presidios were actually small forts where soldiers were posted so they can aid the mission in case they were under threat. These structures survived to this day and are among the most visited tourist sites. These relics and monuments of Spanish colonization form a chain of 21 missions built along El Camino Rey (The Royal Highway) and considered as the refuge of religion and serenity while

Significant Health Care Event Paper Essay Example for Free

Significant Health Care Event Paper Essay Abstract This paper will attempt to discuss events that has changed or affected health care of today. Over the years health care has been influenced by numerous events throughout the United States history. Some events have contributed to the shaping and improvement of the American people’s health care needs. This influence includes society, culture, finance, religion, politics, technology, health trends, the environment, and population (Shi Singh, 2012, p. 9). These influences has contribute to the United States health care evolution that has and continues to impact and access the health care of the American people long with his or her personal values and beliefs. Significant Event’s In the recent years there has been more and more litigation over health care. In today’s society advertisements a springing up all over the place for litigations against health care professionals, health care facilities and pharmacuetal companies. These advertisements are being placed on the television, on the radio, over the internet, on billboards and public transportation. Lawyers are now specializing in significant health care conditions or diseases. This in itself has placed a huge burden on the health care profession and facilities. Some health care facilities have ended up shutting its doors because of the financial burdens of payments, malpractice premiums, and other financial burdens associated with additional procedures to avoid litigation (Satiani, 2004). Health care facilities and  professionals are spending billions of dollars on defensive medicine (Satiani, 2004). These health care dollars are needed elsewhere to improve health care practices such as implementing preventative care, research, and insuring the uninsured. Another effect on the health care is the Patient Protected and Affordable Care Act. The protection and affordable Care act was established to ensure that all Americans have access the quality and affordable health care. The Patient Protected and Affordable Act will help create a healthier health system by contain cost. President Obama has placed a limit of $900 billion to cover the cost of the Patient Protected and Affordable Care Act. This $900 billion will cover 94 percent of Americans according to The Congressional Budget Office making the Patient Protection and Affordable Act completely funded. During the next ten years and beyond the Patient Protection and Affordable act will help to curve the high cost of health care and reduce our state deficit (Responsible Reform for the Middle Class, n.d). Impact on the Historical of Health Care These two events have both a negative and positive impact on health care. The litigations can distract the ability of the American people to receive the adequate health care when needed. Financial facilities and professional are unable to give his or her consumers the consistent level of quality and be cost-effective (Shi Singh, 2012, p. 5). The Patient Protection and Affordable Act give the patient guarantee passage way to quality affordable health care, Improving the quality and efficiency of health care, prevention of chronic disease and improving public health, and improving access to innovative medical therapies (Responsible Reform for the Middle Class, n.d). Excessive litigations lead to the limitation of services that are provided by the health care facilities and professionals. Litigations increase the cost of services, it reduces accessible to facilities, and decreases trained staff. Out of fear health care providers and facilities either increases or decreases unnecessary and necessary procedures because of the high risk for litigation which takes the primary focus off the patient (Catino, 2009). The result of excessive litigation may be stagnation; the system is unable to grow because of the high costs for provision on care and the inability of everyone to receive consistent care. The positive effect of health care litigation occurs because it places a value or consequence on the effect of malpractice. Health care facilities and professional work to develop policies and practices that reduce the harm done to the patient partially because of the cost associated with neglecting to do so. Health care litigation can be a source of help for families who are affected by malpractice, especially if needed to provide further care for those affected. The problem with health care litigation lies, not with those with genuine cases, but with those who attempt to use the system to file false claims for profit. People do not realize that the cost of legal fees is offset by passing the cost to the patient. Unfortunately, most of the money gained during the litigation process does not always go toward the patient/s filing the litigation; according to Satiani (2004), an estimated 57% goes to the attorney and 43% to the patient. Personal Belief on Event’s Significance I believe that excessive litigation is a significant event in health care. It affects many aspects of care and reduces the ability of patients to access the care needed. If people continue to abuse the legal system by filing false claims we will continue to see a rise in the cost of health care. The United States health care system and the citizens must create a culture of honesty. The health care system must provide adequate, timely care to citizens, and citizens avoid false prosecution for personal gain. Conclusion Excessive litigation is an emerging trend in health care. Litigation was intended as a route for citizens to receive compensation for injuries related to malpractice, but is becoming a way of life for the legal system. Lawyers and law offices specialize in health care litigation and most Americans see or hear at least one advertisement for litigation per day. The cost of litigation on the health care system is high and unfortunately the people who pay the cost are the citizens because health care facilities, private practitioners, and insurance companies offset the cost by redirecting it on the patients. The cost of excessive litigation may be too high for citizens to pay. References Catino, M. (2009). Blame culture and defensive medicine. Cognition, Technology, Work, 11(4), 245-253. doi: http://dx.doi.org/10.1007/s10111-009-0130-y Catino, M. (2009). Blame Culture and Defensive Medicine. Cognition, Technology, Work, 11(4). 245-253. doi: http://dx.doi.org/10.1007/s10111-009-0130-y Satiani, B. (2004). The economics of health care litigation. Vascular and Endovascular Surgery.38(3).287-90. doi: 15385744 Shi, L., Singh, D.A. (2012). Delivering Health Care in America: A systems approach (5th ed.).Boston, MA: Jones Barlet. Responsible Reform for the Middle Class. (n.d). Retrieved from http://www.dpc.senate.gov/healthreformbill/healthbill04.pdf

Development of Cryptography Studies

Development of Cryptography Studies 0.1 Abstract This report is an overview of some structures that have heavily influence the course and study of Cryptography the last decades. Initially, we will analyse the structure of some important ciphers such as DES, 3DES and AES by underlying some dark and complicated points and emphasizing the critical  functions called S-boxes. We will then expand of some basic attributes of these block ciphers, for example the running time of them and their hardware and software performance. Finally, we will focus on a highly important aspect of these cryptosystems, security by exploring some of the most significant attacks that have been discovered against them. The paper is concluded with a presentation of the most important results of our investigation. 1 Introduction Cryptography has a very rich history, rooted back in the ancient years. Even Greeks of classical times have demonstrated understanding of ciphers, with the example of Herodotus to be the most well known, who tattooed a message to his slave head on a slaves shaved head and hide it under his regrown hair. Before the modern era, cryptography had an absolute target the achievement of confidentiality of a message. The most crucial years for cryptography were undoubtedly the last century. The decisive step was an investigation of Claude Shannon, the father of information security. In his seminar at 1949, Shannon analysed and illustrated block ciphers and suggest that, if they are combined with some operations that can provide the whole cipher with permutation and substitution, they should be a reasonable option. A block cipher, is an encryption scheme that belongs in the branch of Cryptography that is called symmetric-key Cryptography. This name is justified by the fact that the parties th at are involved in the communication through the cipher use the same secret key. Later designed as iterated product ciphers, block ciphers are deterministic algorithms that operate on fixed length groups of bits, called blocks. The major attribute for a block cipher is that the length of the input, called plaintext, and the length of the output, called ciphertext, is always the same. They take as an input a key of k-bits length and the this key is expanded to many different keys following a sequence of operations, the so called round keys. Typically, a block cipher is built by iteration, using a function called round function. In every round, the round function takes as an input the corresponding message and the round key and produces a new outcome which is oriented to be used in the next round. The final round will produce the ciphertext. Block ciphers have been widely used and dramatically influence the new era of humanity, and more importantly for commercial reasons in industry a nd banking. There is a remarkable variety of examples from block ciphers, although for the rest of this paper we will focus on the most famous examples that dominated the whole area of symmetric-key Cryptography in the new era. These are called DES, 3DES, AES. Blowfish has also attracted the attention since there isnt still any known vulnerability but it will remain outside of the scope of this report. 2 Analysis and Description 2.1 Data Encryption Standard (DES) Nowadays, DES is considered to be insecure, but it had a huge impact in the development of the symmetric-key cryptography for many decades after its invention. It has been designed back in 1976, when the government of the United States realized the overwhelming necessity of an algorithm that could effectively protect government data and safely used for buying products from the international markets. The most interesting difference of DES with its predecessor, Lucifer, which has been designed by Horst Fiestel, is that the key length and the block length has been reduced significantly. Nevertheless, the key length, especially, was from the time that DES was published, under heavy criticism and was actually badly broken in 1997 with the so-called exhaustive search attack. That means that a machine was able to search all the possible keys and find the correct one. DES has a very rich history of attacks and we will examine some of these attacks in more detail later in this paper. The core idea behind DES is the so-called Feistel Network, where a block cipher can built up with the use of some arbitrary functions f0,f1,fd : {0,1}n → {0,1}n. There is a wide variety of block ciphers that have a similar construction, although AES has a completely different construction. The critical point in these kinds of constructions is the structure of these functions, which can vary significantly. Abstractly speaking, the main target is to construct an invertible function F : {0,1}2n → {0,1}2n in order to able to decrypt the ciphertext. DES is basically a 16-round Fiestel network. More specifically, the input is exactly 64 bits, so R0 and L0 are 32 bits each. Obviously, from the diagram above, in every the half of the bits remains unchanged. The other half comes with a sequence of operations. Initially, as specified by the protocol, a permutation of the whole input takes place, followed by a 16-round Fiestel Network. Each function f0,f1,f16 : {0,1}16 → {0 ,1}16 that is used at each round is computed by using the corresponding subkey, fi(x) = F(ki,x) ,in order to make the decryption circuit feasible and manageable from a hardware perspective of view. This subkey is produced by the main key, in the following way: 56 bits are selected from the 64 bits that contains the key, the 56 bits are divided into two 28 bit halves and each half is treated afterwards separately. In every round, both halves are rotated form the left to the right by one or two bits and then 48 bits are selected, 24 from the left and 24 from the right to build the corresponding subkey. After these 16 rounds of the Fiestel network, there is one more permutation before the final output is computed. The following image describes the construction of the fi function. Initially, the input of 32-bits replicates 48-bits with some simple calculations and then the result is XOR with the 48-bits subkey. The 48-bits are splitted to 8 blocks of 6 bits and passed to the S-boxes. This is the most critical point of a block cipher and bad implementation of S-boxes can easily compromise security. A S-box is a function {0,1}6 → {0,1}4 and acts like a look-up table. The selection of these tables is of vital importance and has been a controversial matter for many years. It has been proved that linear S-boxes is definitely not an option. Even a partly linear S-box can run under some kind of attacks. After the implementation of all the S-boxes, a last permutation that maps the 32-bits around, takes place. The decryption circuit follows exactly the inverse procedure. Obviously, the encryption and decryption circuit are almost identical as the only actual difference is the order that the f1,f2,,fd functions are applied. This fact made DES very attractive to hardware developers because they had to implement just one algorithm for both procedures. 2.2 Triple Data Encryption Standard (3DES) As already mentioned, DES has been proved to be vulnerable under certain types of attacks so significant has been made in order to improve the security of DES. For this reason, DES has been replaced by 3DES, which was published in 1998 To begin with, let E : KXM → M be a block cipher and lets define the function 3E : K3 → M as 3E((k1,k2,k3),m) = E(k1,D(k2,E(k3,m))), where D denotes the decryption algorithm. Actually, there are three encryption steps. The main question that arises here is why the middle one is a decryption algorithm and not and encryption algorithm. The answer is simple; this would have lead to the implementation of a single DES, beacause the first and the second DES operations cancel out. will cancel the other. Obviously, the key-size, as it was intended, has been increased to 168-bits, as each of the keys is 56-bits. There are three options for keys; in the first key options all the keys are independent, in the second option k1andk2 are independent and k3 = k1 and in the third all three key are identical, k1 = k2 = k3. The third option is no longer recommended by the NIST( National Institute of Standards and Technology), the first key option is the strongest with a total number of 168 key bits as mentioned above, and the second option is stronger that simply implementing DES twice. 2.3 Why not double DES? 3DES is considered to be a secure block cipher. Nevertheless, a normal question is why 2DES in not an option, as it may not seem easy to beak by brute force with a key-length space 2112. A 2DES can be defined in the following way; 2E(k1,k2),m) = E(k1,E(k2,m)) with a key length 112 bits. This construction turns out to be completely insecure and the reason for this is the meet-in-the-middle attack. Basically, if an attacker has at his disposal an actual message and the corresponding ciphertext, which will be of the same length, he will try to find a pair of key (k1,k2) that E(k1,E(k2,M)) = C. If we apply at both parts of this equation the decryption algorithm, then we get the get E(k2,M) = D(k1,C). So, the attacker will try to figure out which is the appropriate pair of key in order to map the message M and ciphertext C at the same point this also justifies the name of the attack meet-in-themiddle. The attack is structured in two steps: Firstly, the attacker has to build up a table wi th all the 2112 keys and the corresponding encryptions and then sort this list, and secondly, for all possible key that belongs to {0,1}56, he calculates D(k,C) and he looks for a match at the previous table. Whenever he finds the first match, his goal has been achieved. The running time of this attack is 256log(256) + 256log(256) < 263, time that is much smaller than the time that is necessary for brute force attack. 2.4 Advanced Encryption Standard(AES) It is widely acceptable AES has been adopted by the U.S. government and nowadays is used worldwide. As DES was proved insecure and 3DES quite slow, the demand for a more effective encryption scheme grew rapidly and at 1997 NIST requested a new proposal. After some investigation, NIST chose Rijndael as AES at 2000, a cipher that was designed in Belgium. AES, unlikely to its predecessor, its not a Feistel Network. In contrast, it is called a substitution-permutation network because both actions of permutation and substitution take place. AES has a fixed block size of 128-bits, although the key length can vary, 128,192 or 256 bits. Additionally, in every round of AES all bits change while in every round of DES half of the bits remain unchanged. Generally, a substitution permutation networks initial input is operated with an XOR with the corresponding round subkey, then goes through a substitution layer where there are some blocks, configured depending on what the substitution table says and finally a permutation layer follows where all bits are permuted. This procedure is repeated many times until the final outcome is produced. All steps of a substitution permutation network must be reversible in order to be able to decrypt. Specifically for AES, the 128-bits, which are equal to 16-bytes, are handled with the help of a 4X4 matrix with ten repeated rounds to follow. Each element of this matrix is one byte. Each byte comes under the XOR operation with the corresponding round subkey, and then a function is applied in every round that consists of three steps: (1) The Sub-Bytes step, according to which all bytes are replaced with other coming from a look-up table, named Rijndael S-box. This S-box is associated with the Galois Field(28) which is considered to have goo properties. This is a critical operation for the overall structure, as it provides AES with non-linearity. (2) The Shift-Rows step, where the last three rows of the current state are moved some certain positions to the left while the first row remains stable and (3) the Mix-Columns step, where all the bytes of each column of the current state are combined under a linear transformation. The last two steps provide AES with diffusion, a vital property for a secure cipher according to which if we change one bit of the plaintext then almost half of the bits o f the ciphertext will change. It is also considerable that the step Mix-Columns is omitted at the last round of AES. Each subkey is produced by the main key with some kind of expansion similar to the DES. The key expansion is introduced with a number of operations named rotate, Rcon, and S-box and then follows an inner loop in key schedule before the final subkey is produced. 3 Comparison and Attacks 3.1 Running time A real concern about which algorithm is appropriate, especially for commercial use, is the effectiveness and its running time. In general, the larger the block size is, the faster is the algorithm, obviously because larger amount of data is encrypted in one round of operations. Similarly, the smaller the key size is, the faster is the encryption algorithm, because the less key bits are involved in the operations and thus the complexity of them is reduced. A series of experiments have taken place to verify which of the famous encryption algorithms, AES,DES,3DES. Most of these experiments implement these encryption algorithms in Java, although there are some others that used C, most of them at a machine of Pentium 2 or Pentium 4. At most of these experiments, the fastest of these algorithms has been proved to be DES, followed by AES and finally from the 3DES, as it is three times slower than DES. It obviously doesnt make sense to examine the running time of these block ciphers in compl ete isolation with the security that they provide although it is definitely a factor that must be taken into consideration. 3.2 Software and Hardware Implementation Another important aspect that must be examined is the performance of these block ciphers in combination with the available hardware. Again, a lot of study has been carried out and provide us with some clear evidence. In compact architecture, 3DES, DES and AES have displayed very similar performance. In contrast, in high-speed architecture, AES is considered to be almost 4-times than the 3DES and DES. This is happening due to a variety of reasons, amongst them there is no hardware support for DES in modern CPUs, when from the other side there is for AES in increasingly many CPUs, including most targeting servers; hence hardware DES is oà ¯Ã‚ ¬Ã¢â‚¬Å¾oaded to a distant IC, when AES is often in-core. Additionally, DES is often used in CBC mode which makes parallelization inevitable and processed in advance during encryption when AES is mainly used in CTR mode where the possibility of parallelization is available. Finally, DES, and its expansion 3DES is much slower in software than AES, obviously because it was designed back at 1976 before the 8086 processor was designed and uses a lot of bit operations that are not implemented suà ¯Ã‚ ¬Ã†â€™ciently in a processor with a word oriented instruction set. 3.3 Attacks on DES and 3DES As already mentioned earlier at this paper, 2DES has been collapsed from the meet-in-the-middle-attack. Simultaneously, DES, despite its contribution to the overall development of cryptography, has also been defeated by a quite popular attack named exhaustive search. Exhaustive search means that the attacker will search the whole key space and he will find the appropriate, which is unique, in suà ¯Ã‚ ¬Ã†â€™cient amount of time. There are some cases, even in the real world where the attacker can obtain some pairs (mi,ci), where m denotes a message and c the corresponding ciphertext. Under this small requirement, DES was badly broken. To be specific, a company named RSA, back at 1997 announced a problem with the name DES challenge. The company announced six ciphertexts and in parallel announced the first three actual messages and asked for the scientific community to search for the key and use it to obtain the other messages. The same year of the request the challenge had been solved. To go further, the rapid hardware  development was able to create a machine that find the key and solve the problem, equivalently crack DES, within less than one day at the year 1999 with exhaustive search, leading to the assumption that 56-bits length block ciphers should not be used any more. As DES is one of the most famous and controversial block ciphers, it is not entirely surprising that there is a variety of attacks developed against DES, some of them even faster than exhaustive search. Back at 1998, Kocher and Jun demonstrated a very innovative idea by making a side channel attack, introducing a new era for cryptography. Side channels attacks extract information from the physical implementation of the cipher. This type of attack was specifically against smart cards, and is based in power measurement. They actually measured precisely the running time of the smart cards and analysed the diagrams that they obtain from this measurement. In this way, they were able to learn wa s much time was consumed by in each operation from the smart card and find exactly the key. Nowadays, even smart cards are equipped with mechanisms that dont reveal any information of the power consumption there is an attack called differential power analysis, which can steal the secret key after running a lot of time the smart card. It should me mentioned that these attacks are quite general and not for smart cards. In addition, there is another type of a quite highly surprising class of attacks called fault attacks. In this occasion, the attacker can cause a malfunction to a mechanism, lets say to a smart card, for example by warming it up. If he manage to cause and recognise an error at the last round of DES he will be able to discover the secret key. The last attack that we would like to point out is the so called linear cryptanalysis. This is a generic attack and was introduced by Matsui at 1993 and is one of the most realistic, sophisticated and quick attacks on the DES. His a ttacks, and generally in linear cryptanalysis, one tries to find probalistic linear relations between the plaintext, the ciphertext and the secret key. He starts by examining linear relations at the S-boxes of one round and if he succeeds, he will use the to find out linear relations in one-round and then finally them iteratively to find multi-round relations. These relations from round to round are not independent. By combining all these linear relations, the attacker should be able to retrive the secret key. Matsui attack used 244 known plaintexts to find 13 bits of the secret key with a high probability . A similar method was applied to find another 13 bits and then for the remaining 30-bits he applied exhaustive search, he applied exhaustive search, reducing significantly the time that the initial exhaustive search demands. Today, linear cryptanalysis is considered to be, with some improvements, one of the most powerful attacks on DES. Although DES is considered to be faultless and no specific technical vulnerabilities has been found, a high level of linearity at the fifth box of DES has created the possibility for someone to generate this type of attack. Most of the previously referred attacks can also be implemented against 3DES, as the two block ciphers are obviously, highly related. To begin with, an exhaustive search is not suà ¯Ã‚ ¬Ã†â€™cient any more as the key space, if we use three totally independent keys, is huge, especially if we take into consideration the computational power that a strong mahine can demonstrate nowadays. The meet-in-the middle-attack can be applied in a very similar mode, as the attacker can still create a sorted table with the first implementation of DES between one element of the table and the implementation of twice the DES at the opposite direction. The time needed for this attack is 2112, which is considered to be a high level of security, as nowadays a satisfactory level of security against a certain attack is approximately 290, although is still faster in comparison with exhaustive search. Lately, a new attack against block ciphers has been displayed, mainly intended against 3DES and Blowfish and exploits well known kind of vulnerabilities like collision and birthday attacks. Since this is currently under examination and was published only this year, we are not going to expand more. Overall, till today there is not a known and widely acceptable attack that cracks 3DES in a reasonable amount of time. 3.4 Attacks on AES Rijndael has outplayed all other candidates suggested for the AES and so has been analysed quite a bit the last decade. A lot of attacks have been introduced although none of them has hurt AESs security significantly. To begin with, there is a lot of analysis around the meet-in-the-middle attack and some possible improvements of it over the last five years. Gilbert and Minier have proved a very interesting distinguishing property for the first four rounds of AES with the following proposition; lets consider a set of 256 plaintexts where the entry a11 takes all byte values between 0 and 255 exactly once over a given set of plaintexts and all other entries are equal to a constant. If we encrypt this set with three rounds of AES then the function that maps a11 to C11 is determind by 9 fixed 1-byte parameters. C11 denotes the byte values at row i, column j. This proposition was used by them to implement the same idea of the meet-in-the-middle attack. Some further investigation have shown that the number of the parameters, and specifically for 13 or 14 bytes, and this is able to be reduced so the number of the required plaintexts will be minimized. Another famous class of attacks are called cache attacks. Cache is a small part of high speed memory and it aims to keep the CPU as much busy as possible. The catch parameters influence the running time of an algorithm. Specifically, when an element of a data array is called, then we have two possible outcomes. Id the element lies n the cache memory,then the access is instant. In a different situation, the element must be accessed from the main memory. This operation will be executed in significantly different running times and reveal valuable information. We can separate this class of attacks into three families; cold start misses, which arise for the first reference of the data, capacity misses which the magnitude of the element is bigger than the size o the cache and the conflict misses, which may happen in the case of accessing recently accessed data. 4 Conclusion In this paper we examined the structure of popular block ciphers that heavily influenced the development of Cryptography, like DES,3DES and AES and we have compared them in means of running time and software and hardware implementation. We have also considered some basic attacks that have been applied on these cryptosystems. We come to the conclusion that AES is the most safe and practical block ciphers, and this is justified by the fact that is has been chosen for encryption at a series of important applications nowadays. IS it estimated that AES will fully replace 3DES until 2030. There is not any doubt that AES is the most practical and convenient cipher from a hardware and running time perspective. Nevertheless, further investigation must definitely be carried out to ensure the the safety of AES, especially under the increasing enhancement of the technological means, is guaranteed. Finally, the attack Sweet32 is a newly invented attack and must carefully be examined, mainly becau se it is really compromise 3DES security, countermeasures must be taken DES will fully replaced by AES. 5 References [1] Dan Boneh and Victor Shoup, A Graduate Course of Cryptography, August 2015. [2] Diaa Salama Abd Elminaam,Hatem Mohamed Abdual Kader and Mohiy Mohamed Hadhoud, Evaluating The Performance of Symmetric Encryption Algorithms, Higher Technological Institute 10th of Ramadan City, Egypt, (Received Feb. 16, 2009; revised and accepted May 12, 2009) [3] Aamer Nadeem, Dr M. Younus Javed, A Performance Comparison of Data Encryption Algorithms, Department of Computer Engineering, College of Electrical and Mechanical Engineering, National University of Sciences and Technology, Rawalpindi, Pakistan. [4] Akashi Satoh and Sumio Morioka, Hardware-Focused Performance Comparison for the Standard Block Ciphers AES, Camellia, and Triple-DES, Tokyo Research Laboratory IBM Japan Ltd. [5] Huseyin Demirci, Ihsan TaskÄ ±n, Mustafa Coban, and Adnan Baysal, Improved Meet-in-the-Middle Attacks on AES, 2011. [6] Daniel J. Bernstein, Cache-timing attacks on AES, Department of Mathematics, Statistics, and Computer Science (M/C 249) The University of Illinois at Chicago, 2005. [7] Eran Tromer, Dag Arne Osvik and Adi Shamir, Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, 32 Vassar Street, G682, Cambridge, MA 02139, USA and Laboratory for Cryptologic Algorithms, Station 14,  ´Ecole Polytechnique F ´ed ´erale de Lausanne, 1015 Lausanne, Switzerland Received 20 July 2007 and revised 25 June 2009. [8] Anne Canteaut, C ´edric Lauradoux and Andr ´e Seznec, Understanding cache attacks, April 2006. [9] Johannes Blomer and Volker Krummel, Analysis of countermeasures against access driven cache attacks on AES, Faculty of Computer Science, Electrical Engineering and Mathematics University of Paderborn, Germany 2009. [10] Hamdan.O.Alanazi, B.B.Zaidan, A.A.Zaidan, Hamid A.Jalab, M.Shabbir and Y. Al-Nabhani, New Comparative Study Between DES, 3DES and AES within Nine Factors, Journal of Computing, Volume 2, Issue 3, March 2010. [11] Henri Gi lbert and Thomas Peyrin, Super-Sbox Cryptanalysis:Improved Attacks for AES-like Permutations, Orange Labs, France [12] Elisabeth Oswald, Stefan Mangard, Norbert Pramstaller and Vincent Rijmen, Institute for Applied Information Processing and Communciations (IAIK), Austria, 2005. [13] Kai Schramm, Gregor Leander, Patrick Felke and Christof Paar, A Collision-Attack on AES Combining Side Channel and Differential Attack, Horst Gortz Institute for IT Security, Germany 2005. [14] Alex Biryukov and Dmitry Khovratovich, Related-Key Cryptanalysis of the Full AES-192 and AES-256, University of Luxembourg 2011. [15] A Chosen-Plaintext Linear Attack on DES, Lars R. Knudsen and John Erik Mathiassen Department of Informatics, University of Bergen, N5020 Bergen, Norway, 2000. [16] Jawahar Thakur and Nagesh Kumar, DES, AES and Blowfish: Symmetric Key Cryptography, Algorithms Simulation Based Performance Analysis, International Journal of Emerging Technology and Advanced Engineering Website: www.ije tae.com (ISSN 2250-2459, Volume 1, Issue 2, December 2011) [17] Stefan Tillich and Christoph Herbst, Attacking State-of-the-Art Software Countermeasures A Case Study for AES, Institute for Applied Information Processing and Communications, Inffeldgasse 16a, A-8010 Graz, Austria

A Comparison of John Stuart Mill and Immanuel Kants Ethical Theories :: Societal Order Universability

Compare Mill and Kant's ethical theories; which makes a better societal order? John Stuart Mill (1808-73) believed in an ethical theory known as utilitarianism. There are many formulation of this theory. One such is, "Everyone should act in such a way to bring the largest possibly balance of good over evil for everyone involved." However, good is a relative term. What is good? Utilitarians disagreed on this subject. Mill made a distinction between happiness and sheer sensual pleasure. He defines happiness in terms of higher order pleasure (i.e. social enjoyments, intellectual). In his Utilitarianism (1861), Mill described this principle as follows:According to the Greatest Happiness Principle †¦ The ultimate end, end, with reference to and for the sake of which all other things are desirable (whether we are considering our own good or that of other people), is an existence exempt as far as possible from pain, and as rich as possible enjoyments.Therefore, based on this statement, three ideas may be identified: (1) The goodness of an act may be determined by the consequences of that act. (2) Consequences are determined by the amount of happiness or unhappiness caused. (3) A "good" man is one who considers the other man's pleasure (or pain) as equally as his own. Each person's happiness is equally important.Mill believed that a free act is not an undetermined act. It is determined by the unconstrained choice of the person performing the act. Either external or internal forces compel an unfree act. Mill also determined that every situation depends on how you address the situation and that you are only responsible for your feelings and actions. You decide how you feel about what you think you saw.Immanuel Kant (1724-1804) had an interesting ethical system. It is based on a belief that the reason is the final authority for morality. Actions of any sort, he believed, must be undertaken from a sense of duty dictated by reason, and no action performed for expediency or solely in obedience to law or custom can be regarded as moral. A moral act is an act done for the "right" reasons. Kant would argue that to make a promise for the wrong reason is not moral - you might as well not make the promise. You must have a duty code inside of you or it will not come through in your actions otherwise. Our reasoning ability will always allow us to know what our duty is.

Cider House Rules Essay -- essays research papers

The Cider House Rules" is a movie based on John Irving's best selling book. It is a very wonderful, touching, and real 1943 ¡Ã‚ ¦s life story. The story centered on an orphanage child named Homer and a sick doctor, Dr Larch who will have an emotional bond with Homer. I watched the movie before, and my first impression on this movie, I think it is a very good, and relax movie, where you can watch it with your family, although some of the scene may be offended for children. The Cider House Rules, begins in the 1920s in St. Cloud's orphanage in Maine where Homer Wells is born and spends most of his teenage years. Three times he is adopted by good families, but later returned to the orphanage. Dr. Larch, who is in charge there, would just as well have him stay, for he later becomes a good assistant to the doctor in performing abortions and delivering babies. Wally Worthington, whose wealthy parents are in the apple and cider business gets to know Homer when Wally, takes his girlfriend Candy to the St. Cloud's orphanage for an abortion. These three become close friends and Homer accompanies them back to their hometown where he spends the next six months. It's a new life for Homer, and he realizes that his years at the orphanage are just the past and it is time for him to move on. Wally, who became a captain in the Air Force during WW II, crashes his bomber in Burma, and his both of his legs are paralyzed. Candy, who is not good of being left alone, had an affair with Homer, fe...

How evil is presented throughout the play Essay

Show how Shakespeare’s sense of theatre supports the presentation of evil in â€Å"Macbeth.† Shakespeare was born in 1564 at Stratford upon Avon, he was an English poet and playwright. He wrote 38 plays 154 sonnets. He began his successful career in London as an actor and a writer, and later became known as what many say to be the greatest writer in the English language. One of his most successful plays is ‘Macbeth’ it was written at the time king James I was on the throne at the time that the Gunpowder Plot that took place in 1605, and plotted against king James I and tried to blow up the houses of parliament. This is quite significant to the play as it links to people plotting against the king, as Macbeth does. In the end Guy Fawks is burnt, and at the end of the play Macbeth is also murdered. Shakespeare received patronage from the current monarchy if they were pleased with the play he had produced, so he made it appeal to the king or Queen he was writing it for. He did this when he wrote Macbeth, as he Put witches in the play and also based the play around witches and portrayed them as personifying evil this would have appealed to King James I as he wrote a book about witches called Demonology in this book he confirmed his conspiracy about witches being evil supernatural beings that made bad things happen. Shakespeare set the play in the 12th century when it was the17th century so that he could twist the facts of what happened to get across what he wanted to say, about the plot of the witches. Shakespeare tried to make things relevant in the play to King James I. He did this at the start of the play where he used Thunder and Lightening, before the three witches came on this would have appealed to King James I as he expressed very strongly that witches conjured up storms in the book he wrote. Another thing that portrayed evil at the start of the play is that the chant that the witches do ;†Fair is foul and foul is fair,† this shows that evil is about good being bad and bad being good. This links to Macbeth because when he first talks, he says â€Å"so fair and foul a day I have not seen†. He is echoing the words of the witches, and this alerts the audience and makes them think he is connected to them or of the same nature (also evil). Also when the witches say â€Å"when the hurlyburly’s done, when the battle’s lost and won† it makes you curious to think that they may know what is to happen in the future. It also gives you the feeling that the witches are peculiar and supernatural if they can make predictions with such certainty. Shakespeare is also trying to show the power the witches have to make evil happen, that their presence or their words can effect people make them think evil and then become evil, as Macbeth does throughout the play. Macbeth as a victim of supernatural conspiracy as it’s the witches who put the essence of treason in his mind.This is shown when Banquo asks Macbeth â€Å"Good sir, why do you start and seem to fear†. This shows Macbeth is not innately good because seeing the evil of the witches made him fear and a noble man was not to let evil get to him, like Banquo didn’t. This also shows he is susceptible to evil. He also started to have evil thoughts that even started to scare himself he says â€Å"I yield to that suggestion whose horrid image doth unfix my hair, and make my seated heart knock at my ribs†. Macbeth knows it is a sin against God to Murder or even hurt the Lords anointed King. At the start of the play he was honourable and favoured greatly by Duncan who gave him the titles Thane of Cawdor and Thane of Glamis for winning the battle and defeating the king of Norway, but Macbeth above all was a man of action and wanted to know how he could make the prediction of the witches come true and so he didn’t let his evil thoughts get in the way .He says in act 1 scene 4 â€Å"Stars hide your fires, let not light see my black and deep desires†, he wants the stars to stay dark so that he can hide his murderous thoughts. Also dark is associated with bad and evil and light with good and noble. He doesn’t want a starry night so that he can hide his evil thoughts in the darkness away from the light. Macbeth had lots of imagination but he lacked a strong will, when lady Macbeth allures him into Duncan’s murder he went along with the plans although deep down he knew it was morally the wrong thing to do., on the other hand lady Macbeth had a strong will persuading and brainwashing Macbeth, but has no imagination, she is the one who persuades him to commit the ghastly deed but is the one who goes mad. Another aspect of Macbeth’s imagination is when he sees daggers and apparitions before he goes to kill Duncan. Macbeth even Hallucinates when he sees the ghost of Banquo. When Macbeth goes to see the witches they make him feel invincible, they tell him â€Å"no man of woman born can touch him† hearing this he goes and kills all of MacDuffs family (his innocent wife and children) that is because he has descended to evil, he has reached the depths of evil and because evil never triumphs the audience knows he is going be caught, this is when he finds out that the witches tricked him but he does die a noble death because he is brave. Lady Macbeth is portrayed as an evil person in the play but also the source of all the evil from Macbeth. She personifies evil to Macbeth making him do wrong and she guides him into all that he does. This play is written to relate to the biblical story of Adam and Eve where God allows them to eat the fruit from all the trees except the tree of Knowledge of Good and Evil. A serpent persuades Eve to eat from that tree; she does so but also persuades Adam to eat from it. This relates to the story of Macbeth because Lady Macbeth persuades Macbeth to do evil. This is another thing that would have appealed to king James I as he was a religious man who strongly believed in what the bible said. When lady Macbeth reads the letter he has been sent by Macbeth she gets excited and starts having fantastical thoughts, yet she thinks her husband is too kind to do such a thing when she says â€Å"It is too full o ‘th ‘milk of human kindness to catch the nearest way.† She knows she will have to persuade him and she knows just how she will do this â€Å"that I may pour my spirits in thine ear, and chastise with the valour of my tongue.† She is saying she will use her language of persuasion and guide him into the evil to do what she wants him to do. She is the one who induces him and leads him to do it, at first he is reluctant but then she wins him over by saying that he should do it for the love of her, she also challenges his masculinity by doing this so in the end after arguing a won battle because lady Macbeth isn’t backing down, Macbeth finally goes to murder Duncan. Later she entices him by saying that the blame of the murder could be put on the king’s guards, so their crime won’t be discovered. Throughout the play Macbeth goes from noble and good with people referring to him as â€Å"noble Macbeth† and â€Å"valiant cousin† to evil led by the witches. Macbeth was a victim of an evil plot with the witches tricking him and leading him to evil and sin, but the blame can not be put entirely on the witches because although they lead him he was the one who choose to kill Duncan witch was the start of all the bad things that came from it. Macbeth comes to die a noble death, because of his bravery and of this and then the rightful order has been restored and the rightful king is on the throne. This makes stronger the belief that people have that the king is the lords anointed and nobody can do anything about it. The play justifies the position of James I as he is a noble and righteous king . Shakespeare ended the play this was to show that no good comes from witches and from evil and it is a lot better to be noble as you will get a better outcome, Banquo was noble and his son became the king in the end.