Cryptography or cryptology is the practice and study of techniques for secure communication in the presence of third parties called adversaries. More cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, electrical engineering, communication science, physics. Applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, military communications. Cryptography prior to the modern age was synonymous with encryption, the conversion of information from a readable state to apparent nonsense; the originator of an encrypted message shares the decoding technique only with intended recipients to preclude access from adversaries. The cryptography literature uses the names Alice for the sender, Bob for the intended recipient, Eve for the adversary. Since the development of rotor cipher machines in World War I and the advent of computers in World War II, the methods used to carry out cryptology have become complex and its application more widespread.
Modern cryptography is based on mathematical theory and computer science practice. It is theoretically possible to break such a system, but it is infeasible to do so by any known practical means; these schemes are therefore termed computationally secure. There exist information-theoretically secure schemes that provably cannot be broken with unlimited computing power—an example is the one-time pad—but these schemes are more difficult to use in practice than the best theoretically breakable but computationally secure mechanisms; the growth of cryptographic technology has raised a number of legal issues in the information age. Cryptography's potential for use as a tool for espionage and sedition has led many governments to classify it as a weapon and to limit or prohibit its use and export. In some jurisdictions where the use of cryptography is legal, laws permit investigators to compel the disclosure of encryption keys for documents relevant to an investigation. Cryptography plays a major role in digital rights management and copyright infringement of digital media.
The first use of the term cryptograph dates back to the 19th century—originating from The Gold-Bug, a novel by Edgar Allan Poe. Until modern times, cryptography referred exclusively to encryption, the process of converting ordinary information into unintelligible form. Decryption is the reverse, in other words, moving from the unintelligible ciphertext back to plaintext. A cipher is a pair of algorithms that create the reversing decryption; the detailed operation of a cipher is controlled both by the algorithm and in each instance by a "key". The key is a secret a short string of characters, needed to decrypt the ciphertext. Formally, a "cryptosystem" is the ordered list of elements of finite possible plaintexts, finite possible cyphertexts, finite possible keys, the encryption and decryption algorithms which correspond to each key. Keys are important both formally and in actual practice, as ciphers without variable keys can be trivially broken with only the knowledge of the cipher used and are therefore useless for most purposes.
Ciphers were used directly for encryption or decryption without additional procedures such as authentication or integrity checks. There are two kinds of cryptosystems: asymmetric. In symmetric systems the same key is used to decrypt a message. Data manipulation in symmetric systems is faster than asymmetric systems as they use shorter key lengths. Asymmetric systems use a public key to encrypt a private key to decrypt it. Use of asymmetric systems enhances the security of communication. Examples of asymmetric systems include RSA, ECC. Symmetric models include the used AES which replaced the older DES. In colloquial use, the term "code" is used to mean any method of encryption or concealment of meaning. However, in cryptography, code has a more specific meaning, it means the replacement of a unit of plaintext with a code word. Cryptanalysis is the term used for the study of methods for obtaining the meaning of encrypted information without access to the key required to do so; some use the terms cryptography and cryptology interchangeably in English, while others use cryptography to refer to the use and practice of cryptographic techniques and cryptology to refer to the combined study of cryptography and cryptanalysis.
English is more flexible than several other languages in which crypto
Bailey Whitfield'Whit' Diffie, ForMemRS, is an American cryptographer and one of the pioneers of public-key cryptography along with Martin Hellman and Ralph Merkle. Diffie and Hellman's 1976 paper New Directions in Cryptography introduced a radically new method of distributing cryptographic keys, that helped solve key distribution—a fundamental problem in cryptography, their technique became. The article stimulated the immediate public development of a new class of encryption algorithms, the asymmetric key algorithms. After a long career at Sun Microsystems, where he became a Sun Fellow, Diffie served for two and a half years as Vice President for Information Security and Cryptography at the Internet Corporation for Assigned Names and Numbers, he has served as a visiting scholar and affiliate at the Freeman Spogli Institute's Center for International Security and Cooperation at Stanford University, where he is a consulting scholar. Diffie was born in Washington, D. C. the son of Justine Louise, a writer and scholar, Bailey Wallys Diffie, who taught Iberian history and culture at City College of New York.
His interest in cryptography began at "age 10 when his father, a professor, brought home the entire crypto shelf of the City College Library in New York."At Jamaica High School in Queens, New York, Diffie "performed competently" but "never did apply himself to the degree his father hoped." Although he graduated with a local diploma, he did not take the statewide Regents examinations that would have awarded him an academic diploma because he had secured admission to Massachusetts Institute of Technology on the basis of "stratospheric scores on standardized tests." While he received a B. S. in mathematics from the institution in 1965, he remained unengaged and considered transferring to the University of California, Berkeley during the first two years of his undergraduate studies. At MIT, he began to program computers while continuing to perceive the devices "as low class... I thought of myself as a pure mathematician and was interested in partial differential equations and topology and things like that."
From 1965 to 1969, he remained in Greater Boston as a research assistant for the MITRE Corporation in Bedford, Massachusetts. As MITRE was a defense contractor, this position enabled Diffie to avoid the draft. During this period, he helped to develop other non-military applications. In November 1969, Diffie became a research programmer at the Stanford Artificial Intelligence Laboratory, where he worked on LISP 1.6 and correctness problems while cultivating interests in cryptography and computer security under the aegis of John McCarthy. Diffie left SAIL to pursue independent research in cryptography in May 1973; as the most current research in the field during the epoch fell under the classified oversight of the National Security Agency, Diffie "went around doing one of the things I am good at, digging up rare manuscripts in libraries, driving around, visiting friends at universities." He was assisted by Mary Fischer. In the summer of 1974, Diffie and Fischer met with a friend at the Thomas J. Watson Research Center in Yorktown Heights, New York, which housed one of the only nongovernmental cryptographic research groups in the United States.
While group director Alan Konheim "couldn't tell much because of a secrecy order," he advised him to meet with Martin Hellman, a young electrical engineering professor at Stanford University, pursuing a cryptographic research program. A planned half-hour meeting between Diffie and Hellman extended over many hours as they shared ideas and information. Hellman hired Diffie as a grant-funded part-time research programmer for the 1975 spring term. Under his sponsorship, he enrolled as a doctoral student in electrical engineering at Stanford in June 1975. Although it is unclear when he dropped out, Diffie remained employed in Hellman's lab as a research assistant through June 1978. In 1975–76, Diffie and Hellman criticized the NBS proposed Data Encryption Standard because its 56-bit key length was too short to prevent brute-force attack. An audio recording survives of their review of DES at Stanford in 1976 with Dennis Branstad of NBS and representatives of the National Security Agency, their concern was well-founded: subsequent history has shown not only that NSA intervened with IBM and NBS to shorten the key size, but that the short key size enabled the kind of massively parallel key crackers that Hellman and Diffie sketched out.
When these were built outside the classified world, they made it clear that DES was insecure and obsolete. In 2012, a $10,000 commercially available machine could recover a DES key in days. From 1978 to 1991, Diffie was Manager of Secure Systems Research for Northern Telecom in Mountain View, where he designed the key management architecture for the PDSO security system for X.25 networks. In 1991 he joined Sun Microsystems Laboratories in Menlo Park, California as a Distinguished Engineer, working on public policy aspects of cryptogra
DNA computing is a branch of computing which uses DNA, molecular biology hardware, instead of the traditional silicon-based computer technologies. Research and development in this area concerns theory and applications of DNA computing; the term "molectronics" has sometimes been used, but this term has been used for an earlier technology, a then-unsuccessful rival of the first integrated circuits. This field was developed by Leonard Adleman of the University of Southern California, in 1994. Adleman demonstrated a proof-of-concept use of DNA as a form of computation which solved the seven-point Hamiltonian path problem. Since the initial Adleman experiments, advances have been made and various Turing machines have been proven to be constructible. While the initial interest was in using this novel approach to tackle NP-hard problems, it was soon realized that they may not be best suited for this type of computation, several proposals have been made to find a "killer application" for this approach.
In 1997, computer scientist Mitsunori Ogihara working with biologist Animesh Ray suggested one to be the evaluation of Boolean circuits and described an implementation. In 2002, researchers from the Weizmann Institute of Science in Rehovot, unveiled a programmable molecular computing machine composed of enzymes and DNA molecules instead of silicon microchips. On April 28, 2004, Ehud Shapiro, Yaakov Benenson, Binyamin Gil, Uri Ben-Dor, Rivka Adar at the Weizmann Institute announced in the journal Nature that they had constructed a DNA computer coupled with an input and output module which would theoretically be capable of diagnosing cancerous activity within a cell, releasing an anti-cancer drug upon diagnosis. In January 2013, researchers were able to store a JPEG photograph, a set of Shakespearean sonnets, an audio file of Martin Luther King, Jr.'s speech I Have a Dream on DNA digital data storage. In March 2013, researchers created a transcriptor. In August 2016, researchers used the CRISPR gene-editing system to insert a GIF of a galloping horse and rider into the DNA of living bacteria.
Latest research on DNA computing can perform reversible DNA computing bringing it one step closer to the silicon-based computing used in PC. In particular, John Reif and his group at Duke University proposed two different techniques to reuse the computing DNA complexes; the first design uses dsDNA gates. While both the designs face some issues such as reaction leaks, this is a significant breakthrough in the field of DNA computing; the organisation and complexity of all living beings is based on a coding system functioning with four key components of the DNA-molecule. Because of this, the DNA is suited as a medium for data processing. According to different calculations a DNA-computer with one liter of fluid containing six grams of DNA could have a memory capacity of 3072 exabytes; the theoretical maximum data transfer speed would be enormous due to the massive parallelism of the calculations. Therefore, about 1000 petaFLOPS could be reached, while today's most powerful computers do not go above a few dozen.
The slow processing speed of a DNA-computer is compensated by its potential to make a high amount of multiple parallel computations. This allows the system to take a similar amount of time for a complex calculation as for a simple one; this is achieved by the fact that millions or billions of molecules interact with each other simultaneously. However, it is much harder to analyze the answers given by a DNA-Computer than by a digital one. In 1994 Leonard Adleman presented the first prototype of a DNA-Computer; the TT-100 was a test tube filled with 100 microliters of a DNA-solution. He managed to solve an instance of the directed Hamiltonian path problem. In Aldeman's experiment the Hamiltonian Path Problem was implemented notationally as “travelling salesman problem”. For this purpose, different DNA-fragments were created, each one of them representing a city that had to be visited; every one of these fragments is capable of a linkage with the other fragments created. These DNA-fragments were mixed in a test tube.
Within seconds, the small fragments form bigger ones. Through a chemical reaction, the DNA-fragments representing the longer routes were eliminated; the remains are the solution to the problem. However, current technical limitations prevent evaluation of the results. Therefore, the experiment isn’t suitable for application, but it is a proof of concept. First results to these problems were obtained by Leonard Adleman In 1994: Solving a Hamiltonian path in a graph with 7 summits. In 2002: Solving a NP-complete problem as well as a 3-SAT problem with 20 variables. In 2002, J. Macdonald, D. Stefanovic and Mr. Stojanovic created a DNA computer able to play tic-tac-toe against a human player; the calculator consists of nine bins corresponding to the nine squares of the game. Each bin contains various combinations of DNA enzymes; the substrate itself is composed of a DNA strand onto, grafted a fluorescent chemical group at one end, the other end, a repressor group. Fluorescence is only active; the DNA enzymes simulate logical functions.
For example, such a DNA will unfold if two specific types of DNA strand are introduced to reproduce the logic function AND. By default, the computer is considered to have played first in the central square; the human pla
University of Southern California
The University of Southern California is a private research university in Los Angeles, California. Founded in 1880, it is the oldest private research university in California. For the 2018–19 academic year, there were 20,000 students enrolled in four-year undergraduate programs. USC has 27,500 graduate and professional students in a number of different programs, including business, engineering, social work, occupational therapy and medicine, it is the largest private employer in the city of Los Angeles, generates $8 billion in economic impact on Los Angeles and California. USC is the birthplace of the Domain Name System. Other technologies invented at USC include DNA computing, dynamic programming, image compression, VoIP, antivirus software. USC's alumni include a total of 11 Rhodes Scholars and 12 Marshall Scholars; as of October 2018, nine Nobel laureates, six MacArthur Fellows, one Turing Award winner have been affiliated with the university. USC sponsors a variety of intercollegiate sports and competes in the National Collegiate Athletic Association as a member of the Pac-12 Conference.
Members of USC's sports teams, the Trojans, have won 104 NCAA team championships, ranking them third in the United States, 399 NCAA individual championships, ranking them second in the United States. Trojan athletes have won 288 medals at the Olympic Games, more than any other university in the United States. In 1969, it joined the Association of American Universities. USC has had a total of 521 football players drafted to the National Football League, the second-highest number of drafted players in the country; the University of Southern California was founded following the efforts of Judge Robert M. Widney, who helped secure donations from several key figures in early Los Angeles history: a Protestant nurseryman, Ozro Childs, an Irish Catholic former-Governor, John Gately Downey, a German Jewish banker, Isaias W. Hellman; the three donated 308 lots of land to establish the campus and provided the necessary seed money for the construction of the first buildings. Operated in affiliation with the Methodist Church, the school mandated from the start that "no student would be denied admission because of race."
The university is no longer affiliated with any church, having severed formal ties in 1952. When USC opened in 1880, tuition was $15.00 per term and students were not allowed to leave town without the knowledge and consent of the university president. The school had an enrollment of 53 students and a faculty of 10; the city lacked paved streets, electric lights, a reliable fire alarm system. Its first graduating class in 1884 was a class of three—two males and female valedictorian Minnie C. Miltimore; the colors of USC are cardinal and gold, which were approved by USC's third president, the Reverend George W. White, in 1896. In 1958, the shade of gold, more of an orange color, was changed to a more yellow shade; the letterman's awards were the first to make the change. USC students and athletes are known as Trojans, epitomized by the Trojan Shrine, nicknamed "Tommy Trojan", near the center of campus; until 1912, USC students were known as Fighting Methodists or Wesleyans, though neither name was approved by the university.
During a fateful track and field meet with Stanford University, the USC team was beaten early and conclusively. After only the first few events, it seemed implausible USC would win. After this contest, Los Angeles Times sportswriter Owen Bird reported the USC athletes "fought on like the Trojans of antiquity", the president of the university at the time, George F. Bovard, approved the name officially. During World War II, USC was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a Navy commission. USC is responsible for $8 billion in economic output in Los Angeles County. On May 1, 2014, USC was named as one of many higher education institutions under investigation by the Office of Civil Rights for potential Title IX violations by Barack Obama's White House Task Force to Protect Students from Sexual Assault. USC is under a concurrent Title IX investigation for potential anti-male bias in disciplinary proceedings, as well as denial of counseling resources to male students, as of 8 March 2016.
In 2017, the university came into the national spotlight when the Los Angeles Times published information about Carmen A. Puliafito, the dean of USC's medical school. After accusations of drug use, he resigned from his position as dean in 2016 and was fired from the school the following year after the news stories were published, his medical license was subsequently suspended pending a decision. The following year, the Los Angeles Times broke another story about USC focusing on George Tyndall, a gynecologist accused of abusing 52 patients at USC; the reports span from 1990 to 2016 and include using racist and sexual language, conducting exams without gloves and taking pictures of his patients' genitals. Inside Higher Ed noted that there have been "other incidents in which the university is perceived to have failed to act on misconduct by powerful officials" when it reported that the university's president, C. L. Max Nikias, is resigning. Tyndall was fired in 2017 after reaching a settlement with the university.
The school did not report him to state medical authorities or law enforcement at the time, though the LAPD is now investigatin
Ralph C. Merkle is a computer scientist, he is one of the inventors of public key cryptography, the inventor of cryptographic hashing, more a researcher and speaker of cryonics. While an undergraduate, Merkle devised Merkle's Puzzles, a scheme for communication over an insecure channel, as part of a class project; the scheme is now recognized to be an early example of public key cryptography. He co-invented the Merkle–Hellman knapsack cryptosystem, invented cryptographic hashing, invented Merkle trees. While at Xerox PARC, Merkle designed the Khufu and Khafre block ciphers, the Snefru hash function. Merkle was the manager of compiler development at Elxsi from 1980. In 1988, he became a research scientist at Xerox PARC. In 1999 he became a nanotechnology theorist for Zyvex. In 2003 he became a Distinguished Professor at Georgia Tech, where he led the Georgia Tech Information Security Center. In 2006 he returned to the San Francisco Bay Area, where he has been a senior research fellow at IMM, a faculty member at Singularity University, a board member of the Alcor Life Extension Foundation.
He was awarded the IEEE Richard W. Hamming Medal in 2010. Ralph Merkle is a grandnephew of baseball star Fred Merkle. Merkle is married to the video game designer best known for her game, River Raid. Merkle is on the Board of Directors of the cryonics organization Alcor Life Extension Foundation. Merkle appears in the science fiction novel The Diamond Age, involving nanotechnology. 1996 Paris Kanellakis Award for the Invention of Public Key Cryptography. 1998 Feynman Prize in Nanotechnology for computational modeling of molecular tools for atomically-precise chemical reactions 1999 IEEE Koji Kobayashi Computers and Communications Award 2000 RSA Award for Excellence in Mathematics for the invention of public key cryptography. 2008 International Association for Cryptographic Research fellow for the invention of public key cryptography. 2010 IEEE Hamming Medal for the invention of public key cryptography 2011 Computer History Museum Fellow "for his work, with Whitfield Diffie and Martin Hellman, on public key cryptography."
2011 National Inventors Hall of Fame, for the invention of public key cryptography 2012 National Cyber Security Hall of Fame inductee Other references: Ralph C. Merkle, Secrecy and public key systems, UMI Research Press, 1982, ISBN 0-8357-1384-9. Robert A. Freitas Jr. Ralph C. Merkle, Kinematic Self-Replicating Machines, Landes Bioscience, 2004, ISBN 1-57059-690-5. Paul Kantor, Gheorghe Mureşan, Fred Roberts, Daniel Zeng, Frei-Yue Wang, Hsinchun Chen, Ralph Merkle, "Intelligence and Security Informatics": IEEE International Conference on Intelligence and Security Informatics, ISI 2005, Atlanta, GA, US, May 19–20... Springer, 2005, ISBN 3-540-25999-6. Interview at Google Videos in the Death in the Deep Freeze documentary Nova Southeastern University, Nanotechnology Expert Ralph Merkle to Speak on "Life and Death" Ralph Merkle's personal website Oral history interview with Martin Hellman – from 2004, Palo Alto, California. Charles Babbage Institute, University of Minnesota, Minneapolis. Hellman describes his invention of public key cryptography with collaborators Whitfield Diffie and Ralph Merkle at Stanford University in the mid-1970s.
He relates his subsequent work in cryptography with Steve Pohlig and others
The ACM A. M. Turing Award is an annual prize given by the Association for Computing Machinery to an individual selected for contributions "of lasting and major technical importance to the computer field"; the Turing Award is recognized as the highest distinction in computer science and the "Nobel Prize of computing". The award is named after Alan Turing, a British mathematician and reader in mathematics at the University of Manchester. Turing is credited as being the key founder of theoretical computer science and artificial intelligence. From 2007 to 2013, the award was accompanied by an additional prize of US $250,000, with financial support provided by Intel and Google. Since 2014, the award has been accompanied by a prize of US $1 million, with financial support provided by Google; the first recipient, in 1966, was Alan Perlis, of Carnegie Mellon University. The first female recipient was Frances E. Allen of IBM in 2006. List of ACM Awards List of science and technology awards List of prizes named after people IEEE John von Neumann Medal List of Turing Award laureates by university affiliation Turing Lecture Nobel Prize Schock Prize Nevanlinna Prize Kanellakis Award Millennium Technology Prize ACM Chronological listing of Turing Laureates Visualizing Turing Award Laureates ACM A.
M. Turing Award Centenary Celebration ACM A. M. Turing Award Laureate Interviews Celebration of 50 Years of the ACM A. M. Turing Award ACM A. M. Turing Award by SFBayACM
In mathematics and computer science, an algorithm is an unambiguous specification of how to solve a class of problems. Algorithms can perform calculation, data processing, automated reasoning, other tasks; as an effective method, an algorithm can be expressed within a finite amount of space and time and in a well-defined formal language for calculating a function. Starting from an initial state and initial input, the instructions describe a computation that, when executed, proceeds through a finite number of well-defined successive states producing "output" and terminating at a final ending state; the transition from one state to the next is not deterministic. The concept of algorithm has existed for centuries. Greek mathematicians used algorithms in the sieve of Eratosthenes for finding prime numbers, the Euclidean algorithm for finding the greatest common divisor of two numbers; the word algorithm itself is derived from the 9th century mathematician Muḥammad ibn Mūsā al-Khwārizmī, Latinized Algoritmi.
A partial formalization of what would become the modern concept of algorithm began with attempts to solve the Entscheidungsproblem posed by David Hilbert in 1928. Formalizations were framed as attempts to define "effective calculability" or "effective method"; those formalizations included the Gödel–Herbrand–Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's Formulation 1 of 1936, Alan Turing's Turing machines of 1936–37 and 1939. The word'algorithm' has its roots in Latinizing the name of Muhammad ibn Musa al-Khwarizmi in a first step to algorismus. Al-Khwārizmī was a Persian mathematician, astronomer and scholar in the House of Wisdom in Baghdad, whose name means'the native of Khwarazm', a region, part of Greater Iran and is now in Uzbekistan. About 825, al-Khwarizmi wrote an Arabic language treatise on the Hindu–Arabic numeral system, translated into Latin during the 12th century under the title Algoritmi de numero Indorum; this title means "Algoritmi on the numbers of the Indians", where "Algoritmi" was the translator's Latinization of Al-Khwarizmi's name.
Al-Khwarizmi was the most read mathematician in Europe in the late Middle Ages through another of his books, the Algebra. In late medieval Latin, English'algorism', the corruption of his name meant the "decimal number system". In the 15th century, under the influence of the Greek word ἀριθμός'number', the Latin word was altered to algorithmus, the corresponding English term'algorithm' is first attested in the 17th century. In English, it was first used in about 1230 and by Chaucer in 1391. English adopted the French term, but it wasn't until the late 19th century that "algorithm" took on the meaning that it has in modern English. Another early use of the word is from 1240, in a manual titled Carmen de Algorismo composed by Alexandre de Villedieu, it begins thus: Haec algorismus ars praesens dicitur, in qua / Talibus Indorum fruimur bis quinque figuris. Which translates as: Algorism is the art by which at present we use those Indian figures, which number two times five; the poem is a few hundred lines long and summarizes the art of calculating with the new style of Indian dice, or Talibus Indorum, or Hindu numerals.
An informal definition could be "a set of rules that defines a sequence of operations". Which would include all computer programs, including programs that do not perform numeric calculations. A program is only an algorithm if it stops eventually. A prototypical example of an algorithm is the Euclidean algorithm to determine the maximum common divisor of two integers. Boolos, Jeffrey & 1974, 1999 offer an informal meaning of the word in the following quotation: No human being can write fast enough, or long enough, or small enough† to list all members of an enumerably infinite set by writing out their names, one after another, in some notation, but humans can do something useful, in the case of certain enumerably infinite sets: They can give explicit instructions for determining the nth member of the set, for arbitrary finite n. Such instructions are to be given quite explicitly, in a form in which they could be followed by a computing machine, or by a human, capable of carrying out only elementary operations on symbols.
An "enumerably infinite set" is one whose elements can be put into one-to-one correspondence with the integers. Thus and Jeffrey are saying that an algorithm implies instructions for a process that "creates" output integers from an arbitrary "input" integer or integers that, in theory, can be arbitrarily large, thus an algorithm can be an algebraic equation such as y = m + n – two arbitrary "input variables" m and n that produce an output y. But various authors' attempts to define the notion indicate that the word implies much more than this, something on the order of: Precise instructions for a fast, efficient, "good" process that specifies the "moves" of "the computer" to find and process arbitrary input integers/symbols m and n, symbols + and =... and "effectively" produce, in a "reasonable" time, output-integer y at a specified place and in a specified format