Blowfish Algorithm Advantages and Disadvantages

Blowfish Algorithm Advantages and Disadvantages Blowfish is a keyed (piece of information that determines the functional output of a cryptographic algorithm or cipher), symmetric cryptographic block cipher. It was designed by Bruce Schneier in 1993. Since then it has been analyzed considerably, and it is slowly gaining acceptance as a strong encryption algorithm. Blowfish is license-free and is available free for all uses. It is also a symmetric block cipher that can be used as a drop-in replacement for DES or IDEA. It takes a variable-length key, from 32 bits to 448 bits, making it ideal for both domestic and exportable use. Blowfish is also one of the fastest block ciphers in public use, making it ideal for a product that functions on a wide variety of processors found in mobile phones as well as in notebook and desktop computers. The first implementation of the Blowfish Algorithm in LabVIEW. With this set of subvi’s one can encrypt data in LabVIEW without the need of external software. This can be used to send data secu rely over Data socket as well as TCP and UDP communications along with protect remote control systems from unauthorized access, by encrypting the control communications. .( B. Schneier, Applied Cryptography, John Wiley & Sons, New York, 1994.) 3.2 Strategies and Mechanisms Blowfish has a 64-bit block size and a key length of somewhere from 32 bits to 448 bits. The algorithm consists of two parts. One is a key-expansion part and one more is a data- encryption part. Key expansion converts a key of at most 448 bits into several subkey arrays totaling 4168 bytes. It is a 16-round Feistel cipher and uses large key-dependent S-boxes (basic component of symmetric key algorithms which performs substitution). Each round consists of a keydependent permutation, and a keydependent substitution. It is also similar in structure to CAST-128, which uses fixed S-boxes. Blowfish is suitable for application where the key does not change frequently, like a communication link or an automatic file encryp tor. It is significantly faster than most encryption algorithm when on 32-bit microprocessor with large data caches. (Fast Software Encryption, Cambridge Security Workshop Proceedings December 1993) 3.3 The Feistel structure of Blowfish A Fiestel network is a general method of transforming any function (generally called F- function) into a permutation. It was inented by Horst Fiestel and has been used in many block chiper designed. The diagram below shows the action of Blowfish. Each line represents 32 bits. The algorithm keeps two subkey arrays: the 18-entry P-array and four 256-entry S-boxes. The S-boxes accept 8-bit input and produce 32-bit output. One entry of the P-array is used every round, and after the final round, each half of the data block is XORed with one of the two remaining unused P-entries. The diagram to the right shows Blowfish’s F-function. The function splits the 32-bit input into four eight-bit quarters, and uses the quarters as input to the S-boxes. The outputs are added modulo 232 and XORed to produce the final 32-bit output. Since Blowfish is a Feistel network, it can be inverted simply by XO7Ring P17 and P18 to the cipher text block, then using the P-entries in reverse order. Blowfish’s algorithm initialize with the P-array and S-boxes. The secret key is then XORed with the P-entries in order and then use the same method to encrypt all the zero string. The consequential ciphertext replaces P1 and P2 then encrypt the new P1 and P2 with the modified subkeys. Now the output is P3 and P4. Altogether Blowfish algorithm will repeat 521 times in order to calculate new subkeys for the P-array and the four S-boxes. It is about 4KB data is processed.

Health information system Essay Example | Topics and Well Written Essays - 1250 words

Health information system - Essay Example Furthermore, distribution and access to to healthcare is determined by income and standards of living. These features form a social pattern in health that tends to shape health dynamics with respect to certain social requirements. It is important to note with complete patient data, avoidable hospital visits are reduced. Some hospitals use other forms of communication such as email and telephone to reach and support patients from home by checking their health records. For instance, physicians use EHR to determine a patients' health concern. An integrated and comprehensive health record transfers the trend of health care to an efficient approach while maintaining the quality of health care. This results in minimal wastage on financial implications to the hospital, patient and government. Importance of aligned financial incentives. Health outcomes for the population are seen as being influenced by the operation of the capitalist economic system at two levels. Within the capitalist socie ties, health matters have progressed with refined technology in drug production. Poor societies are more likely to fall ill compared to richer societies. Poor disease prevention measures, minimal awareness initiatives by stakeholders, poorly funded research and costly treatment procedures are likely to affect access to health by poor clusters of people. These are some of results of inadequate health data (Gruber, Cummings, LeBlanc, & Smith, 2009). For instance, patients in the least developed areas have been subjected to low quality medication and clinical care. As a result, many people die out of preventable diseases due to early detection or lack of treatment fees. With health records on such scenarios, it would be easy for health providers make adequate arrangements for such people. Meadows Ginny (2002) asserts that, â€Å"Utilizing clinical information systems, an informatics nurse can help other nurses explore and understand the informational and cognitive foundations of their profession. The ability to electronically record, integrate, and analyze data and information enables nurses to quickly move to the synthesis of nursing knowledge and the development of nursing wisdom, which they can then apply to affect patient care.† (Meadows, 2002). It is important to note that the rich controls the health organizations, health research institutions and drug distribution, thus making it difficult for the poor people to make any significant decision or policy on health matters. This has been achieved in some areas through creating enforcement departments within institutions to monitor progress and recommend necessary changes. EHS is important in generating information on how to tackle socioeconomic differences in health care and health policies in any nation are important for equal access to health facilities (Kaufman, Roberts, Merrill, Lai, & Bakken, 2006). This should address areas such as health information technology to shape a coordinated and focused n ational policy in support of patient care. A socially supportive atmosphere prompts the adoption of healthy behaviors. This can be realized when all people have equal and unlimited access to health facilities irrespective of class. Electronic health record (EHS) helps in adopting a patient-centerdness approach that involves shared decisions, outcome

Black people in south africa in the 90 s Essay Example | Topics and Well Written Essays - 1500 words

Black people in south africa in the 90 s - Essay Example Though the transfer and sharing of political power is long a matter of the past, the leveling of economic disparities among the non-White peoples of South Africa remains an elusive and as yet unrealized goal. Africa in general, though South Africa in particular, has in the last twenty years been a testing ground for a variety of programs and initiatives to heal racial divisions and remedy racial and social inequities. â€Å"At a more general level, there is Africa’s role in the broad redefinition of international morality and law. Africa, perhaps more than any other continent, has helped to make domestic racism in a particular society an issue of international relevance† (Mazrui 304). The paradox is such that though South Africa led the way in redressing the political wrongs left by colonialism, it has largely faltered in fixing the socio-economic ones. It is that disparity which stands before us here. The Union of South Africa was formed into a dominion of the British Empire in 1910, whereupon racial segregation and economic isolation became an institutionalized policy of the white-dominated government (South Africa 1998). Looking back, this was by far the decision which would have the greatest consequences upon the future of the country. Even if the ways and means whereby race-based economic disparities continued to plague South Africa’s black population throughout the 1990’s were as widespread as the disparities themselves, one area for which the country should receive praise is in the realm of literacy rates and infant mortality. By 2000 literacy rates had risen from their pre-1991 level of some 77% to approximately 88% of the population, a marked increase. This successfully solved the lack of basic reading skills in those members of the population who had until then been ignored or denied basic access to education. As well, infant mortality levels have dropped f rom 49% in 1990 to 46% in 2007, a change which can be directly attributed