Online examination system Essay Example for Free

Online examination system Essay The cellular concept, cellular frequency planning, link control, handoffs, power control, traffic capacity, propagation modelling, digital transmission techniques, fading mitigation, multiple access techniques, wireless networking, examples of current and future wireless standards. Introduction and overview (1 Lecture) Introduction to Cryptography: (2 lectures) Terminology steganography, substitution and transformation ciphers, XOR,  one-time pads, Protocol Building Blocks: (3 Lectures) Communications using symmetric cryptography, one-way hash functions, communications using public-key cryptography, digital signatures,  Basic Protocols: (2 lectures) Key exchange, authentication, secret splitting, secret sharing, cryptographic protection of databases, Intermediate  Protocols: (2 lectures) Time stamping services, subliminal channel, undeniable digital signatures, Key Length: (2 lecture) Symmetric key length, public-key key length, comparing symmetric and public-key key length, Key Management: (3 Lectures) Generating keys, transferring keys, verifying keys, using keys, updating keys, storing keys, compromised keys, lifetime of keys, destroying keys, public key management,  Algorithm Types and Modes: (10 Lecture) Electronic codebook mode, block replay, cipher block chaining mode, stream ciphers, cipher-feedback mode, output feedback mode, choosing a cipher mode, block ciphers vs. stream ciphers, Choosing an Algorithm, Choosing an algorithm, public-key vs. symmetric cryptography, encrypting communication channels, encrypting data for storage, Security Models, Windows, Linux, Web, Cookies, Biometrics (gummy fingers), Tempest, Viruses, Firewalls, System/Comprehensive Security Analysis Text Book/s Stallings, W and Brown, L., Computer Security: principles and practice, 2nd edition, 2011 Reference Material William Stallings, Cryptography and Network Security, 4th Edition, 2005, ISBN-13: 978-0131873162 Kaufman, Perlman, Speciner, Network Security: Private Communication in a Public World, 2nd Edition, Prentice Hall, 2002, ISBN-13: 978-0130460196 Other books will be used in the course if necessary. Department Of Computer Science Information Technology, HIC Jauharabad Campus Instructional Aids/Resources Assessment Criteria Class Assessment 35% Quizzes and Test 15 Assignment and Presentations 10 Attendance and Class Participations 5 Assignments + Quizzes Mid 25% If Required: Final 40% If Required: Total 100%

Variable Length Hash Algorithm Using RC6

Variable Length Hash Algorithm Using RC6 Hash_RC6 Variable Length Hash Algorithm using RC6 Kirti Aggarwal Dr. Harsh K. Verma ABSTRACT In this paper, we present a hash algorithm using RC6 that can generate hash value of variable length. Hash algorithms play major part in cryptographic security as these algorithms are used to check the integrity of the received message. It is possible to generate hash algorithm using symmetric block cipher. The main idea behind this is that if the symmetric block algorithm is secure then the generated hash function will also be secure [1]. As RC6 is secure against various linear and differential attacks algorithm presented here will also be secure against these attack. The algorithm presented here can have variable number of rounds to generate hash value. It can also have variable block size. Keywords:  Cryptography, Symmetric Encryption, Asymmetric Encryption, Data Integrity, Authentication, Confidentiality, Non-Repudiation, Access Control, Hash, RC6 INTRODUCTION Cryptography is the ability of keeping message secure form others while sending information between participants (Confidentiality). There are many cryptographic algorithms categorized as symmetric encryption algorithm and asymmetric encryption algorithm. Symmetric encryption algorithm is the one that use same shared key from encryption and decryption, while asymmetric algorithm is the one that use different keys from encryption and decryption. With the Confidentiality cryptography also provide other services known as data integrity, authentication, non-repudiation, access control etc. Data Integrity is assuring that data received is same as sent by the sender. Authentication is the ability to assure that communicating party is who that it claims to be. Non-Repudiation is the prevention against the denial by entities involved in the communication. Access Control is the prevention against the unauthorized use of resources [2]. Figure 1. Fundamental of Cryptography Hash Function A cryptographic hash function is any algorithm or subroutine that maps large data sets of variable length to smaller data sets of a fixed length. The values returned by a hash function are called hash values, hash codes, hash sums, checksums or simply hashes. Where h has fixed length. An (accidental or intentional) change to the data will (with very high probability) change the hash value. For a hash function to be considered secure, it must be computationally infeasible to find has a predefined hash value and similarly it must be computationally infeasible to find two messages having same hash value. RC6 RC6 is a symmetric block cipher based on RC5 and designed by Rivest, Sydney, and Yin for RSA security [3]. Like RC5, RC6 is a parameterized algorithm where the block size, the key size, and the number of rounds are variable; again, the upper limit on the key size is 2040 bits [4]. RC6 was designed to meet the requirements of the Advanced Encryption Standard (AES)competition. RC6 proper has ablock sizeof 128 bits and supportskey sizesof 128, 192 and 256 bits, but, like RC5. RC6 can be viewed as interweaving two parallel RC5 encryption processes. It uses an extra multiplication operation not present in RC5 in order to make the rotation dependent on every bit in a word. SHA-256 SHA-256 operates on eight 32-bit words. The message to be hashed is first padded with its length in such a way that the result is a multiple of 512 bits long, and then parsed into 512-bit message blocks M(1);M(2); : : :;M(N). The message blocks are processed one at a time: Beginning with a fixed initial hash value H(0), sequentially compute Where C is the SHA-256 compression function and + means word-wise mod 264 addition. H(N) is the hash of M [5]. SHA-512 SHA-512 is a variant of SHA-256 which operates on eight 64-bit words and block size of 1024 bits. It uses different shift amounts and additive constants, but its structure is otherwise virtually identical, differing only in the number of rounds, which are 80 for SHA-512[15]. HASH FUNCTION A cryptographic hash function is a mathematical transformation that takes a message of arbitrary length and computes a fixed length value also known as hash value, message digest, hash code, hash sum, checksum, etc. Where H is Hash Function, M is variable length message; H is fixed size hash value. Creating hash function is accomplished by iteration. Instead of using a hash function with variable-size input, a function with fixed size input is created and is used a necessary number of times. This fixed size input function is known as compression function. It compresses an n-bit string to create a m-bit string where n is normally greater than m. This scheme is referred to as an iterated cryptographic hash function [6]. These compression function fall into two categories: a function specially designed for the hash function or a symmetric block cipher [2]. Figure 2. Iterated Cryptographic hash Function Characteristics of one way Hash Function: Given M, it is easy to compute h. Given h, it is hard to compute M such that. Given M, it is hard to find another message, M’, such that The whole point of one way hash function is to provide a finger print of M that is unique. In some application one wayness is insufficient; we need an additional requirement called collision-resistance (It is hard to find two random messages, M and M’, such that [1]). Figure 3. Basic Hash Algorithm at sender and receiver Hash Function takes message and an initial value as an input and produces the hash value. The hash value is appended to the message at a time when the message is assumed or known to be correct. The receiver authenticates the message by generating the hash value with the same procedure and compares it with the hash value send by the sender. If both the value matches then the received message is same as it is send by the sender otherwise message has been tampered with. RC6 RC6 [7] is a fully parameterized family of encryption algorithms. A version of RC6 is more accurately specified as RC6-w r bwhere the word size is wbits, encryption consists of a nonnegative number of roundsr, andbdenotes the length of the encryption key in bytes. Since the AES submission is targeted atw= 32 andr= 20, we shall use RC6 as shorthand to refer to such versions. When any other value ofworris intended in the text, the parameter values will be specified as RC6-w r. Of particular relevance to the AES effort will be the versions of RC6 with 16-, 24-, and 32-byte keys [4]. Figure 4. RC6 Encryption For all variants, RC6-w r boperates on units of fourw-bit words using the following six basic operations. integer addition modulo integer subtraction modulo bitwise exclusive-or of w-bit words integer multiplication modulo Rotate to the left by the amount given by the least significant bits of Rotate A to the right, similarly parallel assignment Key Expansion Use two magic constants:- Where:- †¦Ã¢â‚¬ ¦.(base of natural logarithm) †¦Ã¢â‚¬ ¦..() is the odd integer nearest to . INPUT byte key that is preloaded into word array denotes the no of rounds. OUTPUT w-bit round keys . ALGORITHM For do Encryption Four w-bit registers A, B, C, D contain the initial input plain-text as well as the output ciphertext at the end of encryption. The first byte of plaintext is placed in the least significant byte of A; the last byte of plaintext is placed into the most significant byte of D [6]. INPUT Plaintext stored in four w-bit input registers Number r of rounds w-bit round keys OUTPUT Ciphertext stored in ALGORITHM C = C + S[2r + 3] Decryption For decryption of cipher-text load these cipher text into registers A, B, C, D Algorithm uses integer subtraction modulo 2w and right rotation on registers for getting plain text. INPUT Ciphertext stored in four w-bit input registers Number r of rounds w-bit round keys OUTPUT Plaintext stored in ALGORITHM HASH FUNCTION USING RC6 RC6 is a uses 44 words of key material making it more complex to break. RC6 parameterized cipher; the block size can be grown in a straightforward manner to 256 bits and beyond.RC6 has maximum key size of 2040 bits, making the corresponding hash function very fast.20 rounds using RC6 will have all these features which make the hash more efficient and secure. It is possible to use a symmetric block cipher algorithm as a hash function. If the block algorithm is secure, then the one-way hash function will also be secure. One approach is to encrypt the message with the algorithm in CBC mode, a fixed key and an initial vector (IV), the last cipher text block is the hash value. Another more better approach uses the message block as the key, the previous hash value as the output. Here we will use second approach. Algorithm presented here has variable parameters i.e. different parameter value can be taken according to the need. Block size (b), Number of rounds (r), length of hash value (l) are the different variable parameters that are the inputs of the algorithm. The length of hash value (l) should be multiple of 256. First of all padding is done. Message is padded with zeros in a way such that the padded message length is multiple of the block size (b). Then initial vector is needed to generate the hash value. Initial Vector is a piece of data is needed to begin running an algorithm, and is not secret. There are two initial vectors in this algorithm which are used to generate initial hash value. To generate the initial hash value combination of v (size of hash value divided by 256) 256 bits values calculated as follows: After generating initial hash value from initial vectors the message (M) is divided into number of small chunks (n). The size of message chunks should be equal to block size b, after that RC6 key generation is applied on each message block to generate keys that will be used to encrypt the previous hash value to generate next hash value. Initial 256 bits v hash values are encrypted via RC6 using RC6 keys generated from first message block (M1). This is then encrypted again from the keys generated from second message block (M2) and so on until all the message blocks (n) are used. At last all the v final hash values of length 256 bit each are concatenated to generate the final hash value of length l. Number of rounds (r) is divided in to two parts, 3r/4 rounds are used to generate the RC6 keys from the message block and r/4 rounds are used to encrypt the previous hash value to generate next hash value. Figure 5 shows the procedure for hash value of size 512 bits. Figure 5. Hash Value Generation using RC6 PSEUDO CODE INPUT Message M, Number of rounds r, Block size b, Length of hash value l; OUTPUT Final hash value h; ALGORITHM Pad 0s (zeros) at the end of the message so the message length is multiple of b; Divide message into chunks of size b; Repeat step 7 to 21 Load Repeat step 10 to 12 Repeat step 13 to 16 Repeat step 20 Repeat step 22 to 33 Load Repeat step 26 to 30 for do Load Concatenate to get final hash value h PERFORMANCE AND ANALYSIS This algorithm was implemented using java in NetBeans IDE 7.0.1. Following results were obtained on Intel(R) Core(TM) i3 CPU M 370 @ 2.40 GHz 2.39 GHz 32 bit system with 4 GB of RAM running Windows 7 Ultimate. Algorithm presented in this paper is compared with SHA-256 and SHA-512 respectively. Comparison between algorithm presented here and SHA are done on the basis of throughput of the algorithms and time to produce hash value for files of different sizes. To be more accurate the program is executed ten times for each input file and the average of those results are reported here. Results in Figure 6 to Figure 9 and Table 1 for Hash using RC6 are obtained for r=64, b=512, l=256 and these results are compared with SHA-256 which has same value for these parameters. Figure 6. Throughput of RC6_HASH and SHA-256. Figure 7. Bar Graph of Hash value generation time of RC6_HASH and SHA-512 Figure 8. Line Graph of Hash generation time of HASH_RC6 (256) and SHA-256 Figure 9. Execution time saving caused by Hash_RC6 Table 1. Comparison of Hash_RC6 (256) SHA-256 on the basis of Execution Time of different type of Files. Figure 6 shows the throughput of RC6_HASH and SHA-256 the algorithms in KB/sec. Figure 7 shows the Bar Graph hash value generation time (in millisec) of both the algorithms for the file of different sizes (in KB). Figure 8 shows the Line-Graph of execution time according to their file size for each file using algorithms Hash_RC6 (256) and SHA-256. Line graph is more convenient to show that Hash_RC6 (256) performs faster than SHA-256. This Graph also shows that for the file of small size both the algorithms performs approximately same i.e. there is not much of the difference but when the file size increases Hash_RC6 (256) performs much better than the SHA-256. Bar chart in Figure 9 shows the execution time saving caused by Hash_RC6 in percentage in comparison with SHA-256 for different file sizes. It’s greater than 30% for almost all the file sizes and for some of the file sizes its approx 50% that is greater advancement. The average percent execution time saving by Hash_RC6 for hash value of 256 bits over SHA-256 is 40.26. We compare the execution time of each algorithm on different file types like text file, audio file video files, for this purpose we mainly used 10 files and recorded their hash value generation time in milliseconds for these algorithms. List of Input files and their size are given in Table 1. Results in Figure 10 to Figure 13 and Table 2 for Hash using RC6 are obtained for r=80,b=1024,l=512 and these results are compared with SHA-512 which has same value for these parameters. Figure 10. Throughput of RC6_HASH and SHA-512. Figure 11. Bar Graph of Hash value generation time of RC6_HASH and SHA-512 Figure 12. Line Graph of Hash Generation Time of HASH_RC6 (512) and SHA-512 Figure 13. Execution Time saving caused by Hash_RC6 Table 2. Comparison of Hash_RC6 (512) SHA-512 on the basis of Execution Time of different type of Files. Figure 10 shows the throughput of RC6_HASH and SHA-512 the algorithms in KB/sec. Figure 11 shows the Bar Graph of hash value generation time (in millisec) of both the algorithms for the file of different sizes (in KB). Figure 12 shows the Line-Graph of execution time according to their file size for each file using algorithms Hash_RC6 (512) and SHA-512. Line graph is more convenient to show that Hash_RC6 (512) performs faster than SHA-512. This Graph also shows that the difference is not so much for file of small size but when it comes to file of larger size Hash_RC6 (512) is much better than the SHA-512. Bar chart in Figure 13 shows the execution time saving caused by Hash_RC6 (512) in percentage in comparison with SHA-512 for different file sizes. It’s greater than 15% for almost all the file sizes and for some of the file sizes its approx 35% that is greater advancement. The average percent execution time saving by Hash_RC6 for hash value of 512 bits over SHA-512 is 24.625. We compare the execution time of each algorithm on different file types like text file, audio file video files, for this purpose we mainly used 10 files and recorded their hash value generation time in milliseconds for these algorithms. List of Input files and their size are given in Table 2. CONCLUSION In this research paper a new algorithm for generating hash value is presented. This algorithm is generated on a symmetric block cipher known as RC6 and can generate hash value of different sizes. The algorithm can also operate on different block size and different number of rounds. The implementation of algorithm is done using JAVA in NetBeans IDE 7.0.1. on Intel(R) Core(TM) i3 CPU M 370 @ 2.40 GHz 2.39 GHz 32 bit system with 4 GB of RAM running Windows 7 Ultimate. Hash value generated using algorithm presented here are secure against many attack because when a hash algorithm is generated using symmetric block cipher it inherit the properties of underlying cipher. The idea behind this is that if the symmetric block algorithm is secure then the generated hash function will also be secure [1]. Then the algorithm is compared with SHA-256 and SHA-512 for same parameter and on the same environment. The results of comparison conclude that the algorithm present here has better throughput

Helena Maria Viramontes’ The Moths Essay -- Moths Viramontes Essays

Helena Maria Viramontes’ â€Å"The Moths† I was initially drawn to Helena Maria Viramontes’ story â€Å"The Moths† due to the striking similarities between the narrator’s experience and my own experience with being thrust into the role of caretaker for a dying loved one. By tracking a young girl’s transformation through dealings with subjugation (by her culture), freedom (through her grandmother), death (of her grandmother) and grief, Viramontes successfully paints an endearing tale of change. â€Å"The Moths† emphasizes the narrator’s oppression by her household’s religion and by the social structures associated with it, juxtaposed by the freedom for development available within the native curandera custom taught by her grandmother. Through vivid yet subtle symbols, the author weaves a complex web with which to showcase the narrator's oppressive upbringing. Two literary critics whose methods/theories allow us to better comprehend Viramontes message are Jonathan Culler and Stephen Greenblatt. Culler points out that we read literature differently than we read anything else. According to the intertextual theory of how people read literature, readers make assumptions (based on details) that they would not make in real life. During these leaps within which we transform facts into values/themes, the reader creates â€Å"supplementary meaning† to the text by unconsciously setting up tension, also called binary opposition. Culler describes this process in his statement â€Å"The process of thematic interpretation requires us to move from facts towards values, so we can develop each thematic complex, retaining the opposition between them† (294). Though supplementary meaning created within the text can take many forms, within V... ...eedom was found and cultural boundaries were not shattered, simply battered, the narrator’s path was much preferable to that of her sisters (those who conformed to cultural boundaries). Through this story we can see how oppression in certain cultures changes individuals differently, creates tension between those who do not wish to be subjugated and those doing the subjugating, and we see the integral opposition between the path of Catholicism and that of curandismo. WORKS CITED: Contexts for Criticism. Ed. Donald Keesey. New York: McGraw Hill, 2003. ________________. Jonathan Culler. â€Å"Structuralism and Literature. 288-297 ________________. Stephen Greenblatt. â€Å"Culture.† 436-441 The Norton Anthology of Short Fiction. Ed. Cassel & Bausch. New York: W.W. Norton and Company, 2000. Helena Maria Viramontes. â€Å"The Moth’s† 870-874

The Benefits of Participating in Team Sports Essay -- women athletes,

Literature Review "There can be little doubt that intercollegiate athletics is one of the significant filters through which the public looks at American post-secondary education" said Lapchick, Sperber, Telander, and thelin (p. 1). This leads to multiple future college student-athletes being recruited by college coaches. In addition, Mixon, Toma and Cross stated, "The public's image of an institution as well as it’s attractiveness to prospective students are often influenced by the performance of its athletic teams" (p. 1). There are very few individuals who desire not to experience failure, but they rather experience the personal desires accomplishments and success. According to Greendorfer & Kleiber, "men and women may differ in their reasons for athletic participation" (p. 164). This creates a view of intercollegiate athletics being looked upon from two different perspectives. This creates opportunities for different individuals. A person’s development occurs within the classroom, just as well as it does during extracurricular activities. A combination of providing settings for teamwork, motivational goal seeking, and fair play, athletics can build character. A key characteristic for student-athletes is commitment when dealing with these certain activities. The research mainly expresses that participation in college athletics will create positive characteristics towards the academics of student-athletes. Gender In the past, the issue of gender was a highly discussed topic amongst the athletic world. Blinde (1989) initiated "some female athletes have experienced greater difficulties in meeting the simultaneous demands of student and athlete roles" (p. 36). Majority of the terms used by recent female athletic organizat... ...c Psychology, 147, 7-18 Brown, C. & Bohac, J. (1997). Beyound athletic participation: Career development interventions with student-athletes. Journal of College Student Development, 38, 671-673 Chartrand, J.M. & Lent, R.W. (1987). Sports Counseling: Enhancing the development of the student-athlete. Journal of Counseling and development, 40, 151-162. Covington, M., Simons, H., & Van Rheenen, D. (1999). Academic motivation and the student. Journal of College Student Development, 40, 151-162. Hanson, S & Kraus, R. (1998). Women, sports, and science: Do female athletes have an advantage? 71, 93-110. Kuh, G. D. (1995). The other curriculum. Journal of Higher Education, 66, 123-155. Pascarella, E. T., Bohr, L., Nora, A. & Terenzini, P. T. (1995). Intercollegiate athletic participation and freshman-year cognitive outcomes. Journal of Higher Education, 66, 369-387

Astronomy Rules :: Essays Papers

Astronomy Rules Mars would make a lousy host for the Winter Olympics. Yes, there's the lack of air to consider. But more important, Martian snow turns out to be rock hard. Worse, it is melting away at an alarming rate. In fact, Mars may be in the midst of a period of profound climate change, according to a new study that shows dramatic year-to-year losses of snow at the south pole. It is not yet clear, though, if the evidence of a single year's change represents a trend. But the study provides a surprising new view of the nature of the southern ice cap, said Michael Caplinger of Malin Space Science Systems. "It's saying that the permanent cap isn't quite so permanent as we thought," Caplinger said in a telephone interview. A second study of both poles finds that Red Planet snow is more dense and hard than the euphemistic "packed powder" advertised by Eastern ski resorts, and nothing like the soft flakes expected in Utah for the 2002 Olympics. Instead, it's hard as ice. Though unrelated, the two studies were based on observations made by NASA's Mars Global Surveyor and both will be published in the Dec. 7 issue of the journal Science. The combined observations represent an exciting new way to look at Mars' atmosphere and how it interacts over time with the polar caps and even soil at mid-latitudes, said David A. Paige, a researcher at the University of California, Los Angeles. "The new data are showing what's going on on Mars seasonally as well as on interannual time scales in much more detail than we had with previous observations," Paige told SPACE.com. Where the snow is Both of Mars' polar regions are covered in permanent caps of ice. Scientists have known since the 1970s that some of the ice in the north is water ice. There may be water ice in the south, too, but there is no firm evidence. Both poles are covered in a veneer of carbon dioxide ice, popularly called "dry ice" here on Earth. Each cap grows during its winter and recedes in summer. The research into snow density, lead by David E. Smith of NASA's Goddard Space Flight Center, confirm that much of the Martian snow is in fact composed of carbon dioxide. The study involved more than 400 million elevation measurements spanning more than one Martian year, from February 1999 through May of 2001. The orbiting spacecraft bounced a beam of laser light to the surface and back, recording the round-trip time to determine elevations within 4 inches (10 centimeters).

Does Robert Louis Stevenson explore the duality of human nature in Dr. Jekyll and Mr Hyde Essay

Written between 1884 and 1887, Robert Louis Stevenson’s novel, â€Å"the strange case of Dr. Jekyll and Mr Hyde†, is about a well respected physician and his ‘other self’ Mr Hyde. Dr. Jekyll is described as a typical Victorian gentleman . [PD1] Dr Jekyll wanted to develop a potion because he believed he could create a perfectly righteous human being by destroying the evil of the mind and body. When he creates this potion, it doesn’t quite go according to plan. He takes the potion for the first time, but when he goes back to normal, he turns into Mr Hyde without taking the potion. Slowly, Mr Hyde starts to take over Dr Jekyll. When Dr Jekyll turns into Mr Hyde, it changes his appearance, because of this, no one wants to approach him or talk to him. During the time when the book was written, people who looked different or who had disabilities or deformities which are widely accepted today, were not liked and were usually shut away. This is why no one liked or talked to Hyde. There is proof of this in the lines â€Å"I had taken a loathing to the man at first sight† and â€Å"gave me a look so ugly, it brought out the sweat on me like running†. Dr Jekylls idea was that everyone had two sides to them, a good side and an evil side, a side of joy and a side of despair; there is a Mr Hyde in all of us. This was not the only novel of this time that hinted at duality, there were a few of other main plays. Two examples are Deacon Broodie, and Markheim, which is a short story. In the Victorian times, most people had very high morals, and so immoral things were rarely mentioned or talked about. Also, sex is rarely talked about in the book because everyone had such high morals, and so sex is something which would not be written and so was kept away from the public eye. [PD2] Throughout the novel, figurative language is used in various forms. One of the forms used is personification. Personification is used in many ways to try to help the reader to relate to the book, characters, and objects in the book. Another way figurative language is used is in the form of â€Å"similes† by saying things like â€Å"You start a question, and it’s like starting a stone. You sit quietly on the top of a hill; and away the stone goes, starting others; and presently some bland old bird (the last you would have thought of) is knocked on the head in his own back garden and the family have to change their name. No, sir, I make it a rule of mine: the more it looks like Queer Street, the less I ask.†[PD3] The novel was written when the world was not very advanced medically. In the world today, we know of illnesses such as schizophrenia. It is thought that the novel was written about someone who had schizophrenia which would be treated with medication nowadays. jekyll and hyde were indeed the same person and Dr Jekyll didn’t really have â€Å"an evil side† to him, it was just because he had a split personality disorder.

In some countries such as MEDCs population is stabilizing due to low birth rates and low death rates

In some countries such as MEDCs population is stabilizing due to low birth rates and low death rates. However, other countries, mostly in LEDCs, the population isn't stabilizing and instead is increasing. Reasons for this are that people are now living longer due to better health care, while poor education and poor knowledge of birth control means that birth rates are increasing while death rates are decreasing leading to overpopulation. Governments have now begun to recognize the problems caused by population growth and have introduced anti-natalist policies aiming to reduce fertility. Countries suffering from overpopulation are India, Singapore, Nigeria, China and India. Here the governments have implied policies such as later marriages, birth spacing and inheritance laws. Also in India, if a man volunteers for a vasectomy he would receive a free transistor radio. However, perhaps the most famous policy of all is China's ‘one child policy'. China is the third largest country in terms of areas – 9596960 km2. In terms of population it is the biggest nation with 1.2 billion people, who make up 21.5% of the world's total population. The problems China faced were that only 7% of China is land area. While only 50% of this land is farmable and only 13% suitable for arable farming. This situation is then made worse by 94% of the Chinese population living in the badly overpopulated southeast of the country, which consists of 43% of land. While only 6% live in the northwest of the country, which consists of 57% of land. This has led to an imbalance between population and resources. Secondly in 1949, China was made a communist country. At this stage, China sought to maximise its population for military and strategic strength. By 1960 CBR had peaked at 45/1000. The sheer size of the Chinese population put increased demands on services such as food, housing, education and employment. In fact during the 1970s the government feared that further population increases would result in mass starvation by the end of the century. This triggered the government to enforce anti-natalist policies. Options were considered such as: Increase death rate – however not a legitimate government policy. Encourage out migration – too many Chinese for this to be successful. Import more resources – implications for the rest of the world, especially LEDCs. Therefore the only option was to reduce the birth rate, which led to the 1979 ‘one child policy'. This included: Compulsory abortion if a couple already had one child (if a couple managed to escape abortion and have more than one child then there were economic penalties). The introduction of ‘Granny police' – who were older women who went round checking younger women weren't pregnant. Compulsory sterilisation – the government would send in the army to gather men and sterilize them. Later marriages and the use of contraception were also encouraged. The one child policy found greatest success amongst the urban population – where it was more strictly enforced and accepted. Therefore in 1994 the government introduced the ‘new family plan'. This aimed to educate farmers, in rural areas, on the basis that they will naturally come to understand why fewer children means achieving prosperity sooner. The outcomes of the one child policy were that the Birth rate was reduced from 45/1000 to 22/1000. In this respect the policy has therefore been regarded as a success. Couples are wealthier due to economic improvements while they no longer fear the official penalties of increased housing, schooling and medical costs for larger families. However, there have also been a number of problems with the policy. Firstly, there is now an ageing population, which have a number of potential problems in itself. In the early 90s there were about 100 million Chinese people over 60 – which encountered for 9% of the population. By 2030 it is expected to have increased to 25% of the population. This is likely to lead to a limitation in the labour supply. While pensions and retirement benefits are few, and there has never been much state pension for the elderly. Other problems are that most Chinese families want a son. This has led to some female babies being allowed to die after birth through deliberate exposure, neglect or in some areas the feeding of poisonous berries. This leads to a gender imbalance. This could cause problems for China, as it is likely to lead to a considerable amount of unmarried men, causing social instability and a growing demand for prostitution. There is also the tendency for the child to become spoilt. This will be the only child a couple will ever have, therefore all their ambitions and money are channelled into the child's education, well-being and comfort. However, in the course of time such a spoilt child could become the sole support for up to six aged people. In conclusion, without the one child policy china would almost certainly be chaos and an economic mess. Therefore although there are serious problems with the policy, the success of dramatically reducing the population outweighs the potential consequences that China now faces. However, it is not only China who have introduced dramatic anti -natalist policies to reduce the population. Indonesia attempted to even out its differences in population density between its inner and outer islands through a transmigration scheme.