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128-592: Several people came up with the idea for a hotline, including Harvard professor Thomas Schelling , who had worked on nuclear war policy for the Defense Department previously. Schelling credited the pop fiction novel Red Alert (the basis of the film Dr. Strangelove ) with making governments more aware of the benefit of direct communication between the superpowers. In addition, Parade editor Jess Gorkin personally badgered 1960 presidential candidates John F. Kennedy and Richard Nixon , and buttonholed

256-520: A star network topology, this is less of a problem. The key material must be securely disposed of after use, to ensure the key material is never reused and to protect the messages sent. Because the key material must be transported from one endpoint to another, and persist until the message is sent or received, it can be more vulnerable to forensic recovery than the transient plaintext it protects (because of possible data remanence). As traditionally used, one-time pads provide no message authentication ,

384-704: A 21-acre (8.5 ha) campus in the Longwood Medical and Academic Area in Boston , about 3.3 miles (5.3 km) south of the Cambridge campus. Several Harvard-affiliated hospitals and research institutes are also in Longwood, including Beth Israel Deaconess Medical Center , Boston Children's Hospital , Brigham and Women's Hospital , Dana–Farber Cancer Institute , Joslin Diabetes Center , and

512-763: A 358-acre (145 ha) campus in the Allston section of Boston across the John W. Weeks Bridge , which crosses the Charles River and connects the Allston and Cambridge campuses. The university is actively expanding into Allston, where it now owns more land than in Cambridge. Plans include new construction and renovation for the Business School, a hotel and conference center, graduate student housing, Harvard Stadium, and other athletics facilities. In 2021,

640-554: A Free Society , was published by Harvard faculty, which remains one of the most important works in curriculum studies , and women were first admitted to the medical school . Between 1945 and 1960, admissions were standardized to open the university to a more diverse group of students. Following the end of World War II , for example, special exams were developed so veterans could be considered for admission. No longer drawing mostly from prestigious prep schools in New England ,

768-638: A commercial one-time tape system. Each country prepared the keying tapes used to encode its messages and delivered them via their embassy in the other country. A unique advantage of the OTP in this case was that neither country had to reveal more sensitive encryption methods to the other. U.S. Army Special Forces used one-time pads in Vietnam. By using Morse code with one-time pads and continuous wave radio transmission (the carrier for Morse code), they achieved both secrecy and reliable communications. Starting in 1988,

896-432: A computationally unbounded attacker's likelihood of successful forgery is less than p ), but this uses additional random data from the pad, and some of these techniques remove the possibility of implementing the system without a computer. Due to its relative simplicity of implementation, and due to its promise of perfect secrecy, one-time-pad enjoys high popularity among students learning about cryptography, especially as it

1024-486: A dangerously long time. By the time Washington had drafted a reply, a tougher message from Moscow had been received, demanding that U.S. missiles be removed from Turkey . White House advisers thought faster communications could have averted the crisis, and resolved it quickly. The two countries signed the Hot Line Agreement on June 20, 1963 – the first time they formally took action to cut the risk of starting

1152-403: A key read from a punched tape . In its original form, Vernam's system was vulnerable because the key tape was a loop, which was reused whenever the loop made a full cycle. One-time use came later, when Joseph Mauborgne recognized that if the key tape were totally random, then cryptanalysis would be impossible. The "pad" part of the name comes from early implementations where the key material

1280-671: A nuclear war unintentionally. It was used for the first time by U.S. President John F. Kennedy on August 30, 1963. The "hotline", as it would come to be known, was established after the signing of a "Memorandum of Understanding Regarding the Establishment of a Direct Communications Line" on June 20, 1963, in Geneva, Switzerland, by representatives of the Soviet Union and the United States. The Republican Party criticized

1408-514: A one-time pad of letters to encode plaintext directly as in the example below. Leo Marks describes inventing such a system for the British Special Operations Executive during World War II , though he suspected at the time that it was already known in the highly compartmentalized world of cryptography, as for instance at Bletchley Park . The final discovery was made by information theorist Claude Shannon in

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1536-428: A powerful enough quantum computer. One-time pads, however, would remain secure, as perfect secrecy does not depend on assumptions about the computational resources of an attacker. Despite Shannon's proof of its security, the one-time pad has serious drawbacks in practice because it requires: One-time pads solve few current practical problems in cryptography. High-quality ciphers are widely available and their security

1664-444: A priority. During the standoff, official diplomatic messages typically took six hours to deliver; unofficial channels, such as via television network correspondents, had to be used too as they were quicker. The experience of the crisis convinced both sides of the need for better communications. During the crisis, the United States took nearly twelve hours to receive and decode Nikita Khrushchev 's 3,000-word-initial settlement message –

1792-544: A quantum analogue of the one time pad, which can be used to exchange quantum states along a one-way quantum channel with perfect secrecy, which is sometimes used in quantum computing. It can be shown that a shared secret of at least 2n classical bits is required to exchange an n-qubit quantum state along a one-way quantum channel (by analogue with the result that a key of n bits is required to exchange an n bit message with perfect secrecy). A scheme proposed in 2000 achieves this bound. One way to implement this quantum one-time pad

1920-416: A quantum setting. Suppose Alice wishes to send the message hello to Bob . Assume two pads of paper containing identical random sequences of letters were somehow previously produced and securely issued to both. Alice chooses the appropriate unused page from the pad. The way to do this is normally arranged for in advance, as for instance "use the 12th sheet on 1 May", or "use the next available sheet for

2048-399: A serial number and eight lines. Each line had six 5-digit numbers. A page would be used as a work sheet to encode a message and then destroyed. The serial number of the page would be sent with the encoded message. The recipient would reverse the procedure and then destroy his copy of the page. The German foreign office put this system into operation by 1923. A separate notion was the use of

2176-439: A shared secret key to be agreed upon with relatively few messages exchanged and relatively low computational overhead. At a high level, the schemes work by taking advantage of the destructive way quantum states are measured to exchange a secret and detect tampering. In the original BB84 paper, it was proven that the one-time pad, with keys distributed via QKD, is a perfectly secure encryption scheme. However, this result depends on

2304-402: A sharp pencil, and some mental arithmetic . The method can be implemented now as a software program, using data files as input (plaintext), output (ciphertext) and key material (the required random sequence). The exclusive or (XOR) operation is often used to combine the plaintext and the key elements, and is especially attractive on computers since it is usually a native machine instruction and

2432-420: A technique for generating pure randomness is measuring radioactive emissions . In particular, one-time use is absolutely necessary. For example, if p 1 {\displaystyle p_{1}} and p 2 {\displaystyle p_{2}} represent two distinct plaintext messages and they are each encrypted by a common key k {\displaystyle k} , then

2560-587: A union. Bacow retired in June 2023, and on July 1 Claudine Gay , a Harvard professor in the Government and African American Studies departments and Dean of the Faculty of Arts and Sciences , became Harvard's 30th president. In January 2024, just six months into her presidency, Gay resigned following allegations of antisemitism and plagiarism . Gay was succeeded by Alan Garber , the university's provost, who

2688-497: A very large one-time-pad from place to place in a non-suspicious way, but the need to transport the pad physically is a burden compared to the key negotiation protocols of a modern public-key cryptosystem. Such media cannot reliably be erased securely by any means short of physical destruction (e.g., incineration). A 4.7 GB DVD-R full of one-time-pad data, if shredded into particles 1 mm (0.0016 sq in) in size, leaves over 4 megabits of data on each particle. In addition,

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2816-522: Is a private Ivy League research university in Cambridge, Massachusetts , United States. Founded October 28, 1636, and named for its first benefactor, the Puritan clergyman John Harvard , it is the oldest institution of higher learning in the United States. Its influence, wealth, and rankings have made it one of the most prestigious universities in the world. Harvard was founded and authorized by

2944-427: Is an example of post-quantum cryptography, because perfect secrecy is a definition of security that does not depend on the computational resources of the adversary. Consequently, an adversary with a quantum computer would still not be able to gain any more information about a message encrypted with a one time pad than an adversary with just a classical computer. One-time pads have been used in special circumstances since

3072-435: Is by dividing the 2n bit key into n pairs of bits. To encrypt the state, for each pair of bits i in the key, one would apply an X gate to qubit i of the state if and only if the first bit of the pair is 1, and apply a Z gate to qubit i of the state if and only if the second bit of the pair is 1. Decryption involves applying this transformation again, since X and Z are their own inverses. This can be shown to be perfectly secret in

3200-561: Is cancelled, stay home". The attacker's knowledge of the one-time pad is limited to this byte length, which must be maintained for any other content of the message to remain valid. This is different from malleability where the plaintext is not necessarily known. Without knowing the message, the attacker can also flip bits in a message sent with a one-time pad, without the recipient being able to detect it. Because of their similarities, attacks on one-time pads are similar to attacks on stream ciphers . Standard techniques to prevent this, such as

3328-727: Is not currently considered a major worry. Such ciphers are almost always easier to employ than one-time pads because the amount of key material that must be properly and securely generated, distributed and stored is far smaller. Additionally, public key cryptography overcomes the problem of key distribution. High-quality random numbers are difficult to generate. The random number generation functions in most programming language libraries are not suitable for cryptographic use. Even those generators that are suitable for normal cryptographic use, including /dev/random and many hardware random number generators , may make some use of cryptographic functions whose security has not been proven. An example of

3456-514: Is often the first algorithm to be presented and implemented during a course. Such "first" implementations often break the requirements for information theoretical security in one or more ways: Despite its problems, the one-time-pad retains some practical interest. In some hypothetical espionage situations, the one-time pad might be useful because encryption and decryption can be computed by hand with only pencil and paper. Nearly all other high quality ciphers are entirely impractical without computers. In

3584-420: Is some ambiguity to the term "Vernam cipher" because some sources use "Vernam cipher" and "one-time pad" synonymously, while others refer to any additive stream cipher as a "Vernam cipher", including those based on a cryptographically secure pseudorandom number generator (CSPRNG). Frank Miller in 1882 was the first to describe the one-time pad system for securing telegraphy. The next one-time pad system

3712-421: Is the same as the a posteriori probability of a plaintext message M given the corresponding ciphertext. Conventional symmetric encryption algorithms use complex patterns of substitution and transpositions . For the best of these currently in use, it is not known whether there can be a cryptanalytic procedure that can efficiently reverse (or even partially reverse ) these transformations without knowing

3840-526: Is therefore very fast. It is, however, difficult to ensure that the key material is actually random, is used only once, never becomes known to the opposition, and is completely destroyed after use. The auxiliary parts of a software one-time pad implementation present real challenges: secure handling/transmission of plaintext, truly random keys, and one-time-only use of the key. To continue the example from above, suppose Eve intercepts Alice's ciphertext: EQNVZ . If Eve tried every possible key, she would find that

3968-484: Is typically associated with the one-time pad because it provides a way of distributing a long shared secret key securely and efficiently (assuming the existence of practical quantum networking hardware). A QKD algorithm uses properties of quantum mechanical systems to let two parties agree on a shared, uniformly random string. Algorithms for QKD, such as BB84 , are also able to determine whether an adversarial party has been attempting to intercept key material, and allow for

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4096-454: Is used as the hotline. A more realistic depiction of the Hotline was Tom Clancy 's novel The Sum of All Fears from 1991 and its 2002 film adaptation , in which a text-based computer communications system was depicted, resembling the actual Hotline equipment from the 1980s and 1990s. In the novel the isolated and unprepared President and National Security Advisor consistently misinterpret

4224-420: The 1984 Democratic primary and 1984 presidential election and the 2008 Democratic primary elections . In 1984, an advertisement made by Bob Beckel and Roy Spence on behalf of candidate Walter Mondale suggested that "The most awesome, powerful responsibility in the world lies in the hand that picks up this phone." The advertisement was intended to raise questions about candidate Gary Hart 's readiness for

4352-509: The African National Congress (ANC) used disk-based one-time pads as part of a secure communication system between ANC leaders outside South Africa and in-country operatives as part of Operation Vula, a successful effort to build a resistance network inside South Africa. Random numbers on the disk were erased after use. A Belgian flight attendant acted as courier to bring in the pad disks. A regular resupply of new disks

4480-803: The Allston neighborhood of Boston ; and the medical campus in Boston's Longwood Medical Area . Harvard's endowment , valued at $ 50.7 billion , makes it the wealthiest academic institution in the world. Harvard Library , with more than 20 million volumes, is the world's largest academic library . Harvard alumni, faculty, and researchers include 188 living billionaires , eight U.S. presidents , 24 heads of state and 31 heads of government , founders of notable companies, Nobel laureates , Fields Medalists , members of Congress , MacArthur Fellows , Rhodes Scholars , Marshall Scholars , Turing Award Recipients , Pulitzer Prize recipients, and Fulbright Scholars ; by most metrics, Harvard University ranks among

4608-602: The American Civil War , under Harvard president Charles William Eliot 's long tenure from 1869 to 1909, Harvard developed multiple professional schools, which transformed it into a modern research university . In 1900, Harvard co-founded the Association of American Universities . James B. Conant led the university through the Great Depression and World War II , and liberalized admissions after

4736-525: The American Revolution . In the 19th century, Harvard was influenced by Enlightenment Age ideas, including reason and free will, which were widespread among Congregational ministers and which placed these ministers and their congregations at odds with more traditionalist, Calvinist pastors and clergies. Following the death of Hollis Professor of Divinity David Tappan in 1803 and that of Joseph Willard , Harvard's eleventh president,

4864-533: The Carnegie Classification . The medical school consistently ranks first among medical schools for research, and biomedical research is an area of particular strength for the university. More than 11,000 faculty and 1,600 graduate students conduct research at the medical school and its 15 affiliated hospitals and research institutes. In 2019, the medical school and its affiliates attracted $ 1.65 billion in competitive research grants from

4992-494: The Darfur genocide , and tobacco , fossil fuel , and private prison industries. In the late 1980s, during the disinvestment from South Africa movement, student activists erected a symbolic shanty town on Harvard Yard and blockaded a speech by South African Vice Consul Duke Kent-Brown. The university eventually reduced its South African holdings by $ 230 million , out of a total of $ 400 million , in response to

5120-452: The Faculty of Arts and Sciences , including Sever Hall , Harvard Hall , and freshman dormitories . Upperclassmen live in the twelve residential houses , located south of Harvard Yard near the Charles River and on Radcliffe Quadrangle , which formerly housed Radcliffe College students. Each house is a community of undergraduates, faculty deans, and resident tutors, with its own dining hall, library, and recreational facilities. Also on

5248-614: The Graduate School of Arts and Sciences , the John A. Paulson School of Engineering and Applied Sciences (SEAS) , and the Division of Continuing Education , which includes Harvard Summer School and Harvard Extension School . There are nine other graduate and professional faculties and a faculty attacked to the Harvard Radcliffe Institute . There are four Harvard joint programs with MIT , which include

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5376-648: The Harvard John A. Paulson School of Engineering and Applied Sciences expanded into the new Allston-based Science and Engineering Complex (SEC), which is more than 500,000 square feet in size. SEC is adjacent to the Enterprise Research Campus, the Business School, and Harvard Innovation Labs, and designed to encourage technology- and life science-focused startups and collaborations with mature companies. The university's schools of Medicine , Dental Medicine , and Public Health are located on

5504-638: The Harvard–MIT Program in Health Sciences and Technology , the Broad Institute , The Observatory of Economic Complexity , and edX . The university maintains 12 schools, which include: Harvard is a founding member of the Association of American Universities and a preeminent research university with "very high" research activity (R1) and comprehensive doctoral programs across the arts, sciences, engineering, and medicine, according to

5632-566: The Kremlin in the wake of a global Soviet invasion. In "World War Three" , a 2005 episode of the British sci-fi television series Doctor Who , the Slitheen await a phone call to plunge the planet into a nuclear holocaust on an actual red telephone, directly pastiching the cold war fears related to the hotline. The "red phone" was the centerpiece of television commercials used in

5760-503: The Massachusetts General Court , the governing legislature of colonial -era Massachusetts Bay Colony . While never formally affiliated with any denomination , Harvard trained Congregational clergy until its curriculum and student body were gradually secularized in the 18th century. By the 19th century, Harvard emerged as the most prominent academic and cultural institution among the Boston elite . Following

5888-672: The National Institutes of Health , more than twice that of any other university. Harvard Library , the largest academic library in the world with 20.4 million holdings, is centered in Widener Library in Harvard Yard . It includes 25 individual Harvard libraries around the world with a combined staff of more than 800 librarians and personnel. Houghton Library , the Arthur and Elizabeth Schlesinger Library on

6016-524: The Venona project . Because the pad, like all shared secrets , must be passed and kept secure, and the pad has to be at least as long as the message, there is often no point in using a one-time pad, as one can simply send the plain text instead of the pad (as both can be the same size and have to be sent securely). However, once a very long pad has been securely sent (e.g., a computer disk full of random data), it can be used for numerous future messages, until

6144-458: The Vigenère cipher . The numerical values of corresponding message and key letters are added together, modulo 26. So, if key material begins with XMCKL and the message is hello , then the coding would be done as follows: If a number is larger than 25, then the remainder after subtraction of 26 is taken in modular arithmetic fashion. This simply means that if the computations "go past" Z,

6272-658: The White House Situation Room equipment that receives the (translated) hotline message, apparently relayed by the Pentagon-NMCC MOLINK team, is depicted as a teleprinter (and not as a fax machine, the technology already in use at the NMCC itself by that year). A telephone is used in the intro cinematic of the video game Command & Conquer: Red Alert 2 . The call is placed by the US president to

6400-826: The Wyss Institute for Biologically Inspired Engineering . Additional affiliates, including Massachusetts General Hospital , are located throughout Greater Boston . Harvard owns Dumbarton Oaks , a research library in Washington, D.C., Harvard Forest in Petersham, Massachusetts , Concord Field Station in Estabrook Woods in Concord, Massachusetts , the Villa I Tatti research center in Florence , Italy, and

6528-450: The XOR of the two plaintexts p 1 ⊕ p 2 {\displaystyle p_{1}\oplus p_{2}} . (This is because taking the XOR of the common key k {\displaystyle k} with itself yields a constant bitstream of zeros.) p 1 ⊕ p 2 {\displaystyle p_{1}\oplus p_{2}} is then

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6656-432: The one-time pad ( OTP ) is an encryption technique that cannot be cracked , but requires the use of a single-use pre-shared key that is larger than or equal to the size of the message being sent. In this technique, a plaintext is paired with a random secret key (also referred to as a one-time pad ). Then, each bit or character of the plaintext is encrypted by combining it with the corresponding bit or character from

6784-429: The 1940s who recognized and proved the theoretical significance of the one-time pad system. Shannon delivered his results in a classified report in 1945 and published them openly in 1949. At the same time, Soviet information theorist Vladimir Kotelnikov had independently proved the absolute security of the one-time pad; his results were delivered in 1941 in a report that apparently remains classified. There also exists

6912-413: The 20th century, as its endowment burgeoned and prominent intellectuals and professors affiliated with it, Harvard University's reputation as one of the world's most prestigious universities grew notably. The university's enrollment also underwent substantial growth, a product of both the founding of new graduate academic programs and an expansion of the undergraduate college . Radcliffe College emerged as

7040-974: The Center for Hellenic Studies in Greece. https://greece.chs.harvard.edu the Harvard Shanghai Center in Shanghai , China, and Arnold Arboretum in the Jamaica Plain neighborhood of Boston. Harvard is governed by a combination of its Board of Overseers and the President and Fellows of Harvard College , which is also known as the Harvard Corporation. These two bodies, in turn, appoint the President of Harvard University . There are 16,000 staff and faculty, including 2,400 professors, lecturers, and instructors. Harvard has

7168-733: The Harvard Library system include Baker Library/Bloomberg Center at Harvard Business School , Cabot Science Library at Harvard Science Center , Dumbarton Oaks in Washington, D.C. , Gutman Library at the Harvard Graduate School of Education , Harvard Film Archive at the Carpenter Center for the Visual Arts , Houghton Library , and Lamont Library . One-time pad In cryptography ,

7296-732: The History of Women in America, and the Harvard University Archives consist principally of rare and unique materials. The nation's oldest collection of maps, gazetteers, and atlases is stored in Pusey Library on Harvard Yard , which is open to the public. The largest collection of East-Asian language material outside of East Asia is held in Harvard-Yenching Library . Other major libraries in

7424-520: The Pooh , given that a bear is considered the national symbol of Russia . The Soviets also asked, during the Carter administration , that Washington not send routine communications through the hotline. Upon receipt of the message at the NMCC, the message was translated into English, and both the original Russian and the translated English texts are transmitted to the White House Situation Room . However, if

7552-457: The QKD scheme being implemented correctly in practice. Attacks on real-world QKD systems exist. For instance, many systems do not send a single photon (or other object in the desired quantum state) per bit of the key because of practical limitations, and an attacker could intercept and measure some of the photons associated with a message, gaining information about the key (i.e. leaking information about

7680-731: The Russian messages, prompting the Vice President aboard the National Emergency Airborne Command Post to remark "These damned messages over the Hot Line are making things worse instead of better." The protagonist Jack Ryan then communicates information over the Hotline from the Pentagon's NMCC to both country's leaders that defuses the crisis. In the 1990 HBO film By Dawn's Early Light ,

7808-614: The Soviet premier Nikita Khrushchev during a U.S. visit to adopt the idea. During this period Gerard C. Smith , as head of the State Department Policy Planning Staff, proposed direct communication links between Moscow and Washington. Objections from others in the State Department , the U.S. military , and the Kremlin delayed introduction. The 1962 Cuban Missile Crisis made the hotline

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7936-716: The US Nuclear Risk Reduction Center and Russian National Nuclear Risk Reduction Center , which were initiated by Ronald Reagan and Mikhail Gorbachev in 1985 following the Reykjavik Summit to reduce the risk of nuclear war. The negotiations began in May 1986, and the sides agreed in 1987. The sides established NRRCs in Washington and in Moscow, exchanging arms control and confidence building measures notifications, initially including those required by

8064-569: The agreement on Measures to Reduce the Risk of Outbreak of Nuclear War and the 1972 Agreement on the Prevention of Incidents on and over the High Seas, with their duties expanding over the decades to include notifications covering more than 16 treaties and agreements. In 2012, it was announced that a proposal was being negotiated with Moscow to add cyber warfare to the topics to be discussed on

8192-585: The churches when our present ministers shall lie in the dust." In its early years, the college trained many Puritan ministers and offered a classical curriculum based on the English university model many colonial-era Massachusetts leaders experienced at the University of Cambridge , where many of them studied prior to immigrating to British America . Harvard never formally affiliated with any particular Protestant denomination, but its curriculum conformed to

8320-575: The early 1900s. In 1923, they were employed for diplomatic communications by the German diplomatic establishment. The Weimar Republic Diplomatic Service began using the method in about 1920. The breaking of poor Soviet cryptography by the British , with messages made public for political reasons in two instances in the 1920s ( ARCOS case ), appear to have caused the Soviet Union to adopt one-time pads for some purposes by around 1930. KGB spies are also known to have used pencil and paper one-time pads more recently. Examples include Colonel Rudolf Abel , who

8448-616: The encrypted message (i.e., the ciphertext ) provides no information about the original message to a cryptanalyst (except the maximum possible length of the message). This is a very strong notion of security first developed during WWII by Claude Shannon and proved, mathematically, to be true for the one-time pad by Shannon at about the same time. His result was published in the Bell System Technical Journal in 1949. If properly used, one-time pads are secure in this sense even against adversaries with infinite computational power. Shannon proved, using information theoretic considerations, that

8576-445: The equivalent of a running key cipher. If both plaintexts are in a natural language (e.g., English or Russian), each stands a very high chance of being recovered by heuristic cryptanalysis, with possibly a few ambiguities. Of course, a longer message can only be broken for the portion that overlaps a shorter message, plus perhaps a little more by completing a word or phrase. The most famous exploit of this vulnerability occurred with

8704-440: The event of an accidental, unauthorized or unexplained incident involving a nuclear weapon that could increase the risk of nuclear war. Two new satellite communication lines supplemented the terrestrial circuits using two U.S. Intelsat satellites, and two Soviet Molniya II satellites. This arrangement lasted from 1971 to 1978; it made the radio link via Tangier redundant. In May 1983, President Ronald Reagan proposed to upgrade

8832-418: The fax links to be reliable. The Soviets transferred the hotline link to the newer, geostationary Gorizont -class satellites of the Stationar system. In 1988, the US side of the hotline system was located at the National Military Command Center in the Pentagon. Each MOLINK (Moscow Link) team worked an eight-hour shift: a non-commissioned officer looked after the equipment, and a commissioned officer who

8960-409: The female counterpart of Harvard College, becoming one of the most prominent schools in the nation for women. In 1923, a year after the percentage of Jewish students at Harvard reached 20%, A. Lawrence Lowell , the university's 22nd president, unsuccessfully proposed capping the admission of Jewish students to 15% of the undergraduate population. Lowell also refused to mandate forced desegregation in

9088-407: The film Fail-Safe as the "Red 1 / Ultimate 1 Touch phone", and also in Stanley Kubrick's film Dr. Strangelove , both from 1964 and both loosely based on Peter George 's Cold War thriller novel Red Alert from 1958. The 1970 science fiction film Colossus: The Forbin Project depicts the hotline as a sophisticated video conference link. In the 1979 film Meteor a direct telephone link

9216-455: The following year, a struggle broke out over their replacements. In 1805, Henry Ware was elected to replace Tappan as Hollis chair. Two years later, in 1807, liberal Samuel Webber was appointed as Harvard's 13th president, representing a shift from traditional ideas at Harvard to more liberal and Arminian ideas. In 1816, Harvard University launched new language programs in the study of French and Spanish , and appointed George Ticknor

9344-507: The following year. In 1638, the university acquired British North America 's first known printing press . The same year, on his deathbed, John Harvard , a Puritan clergyman who emigrated to the colony from England, bequeathed the emerging college £780 and his library of some 320 volumes; the following year, it was named Harvard College . In 1643, a Harvard publication defined the college's purpose: "advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to

9472-427: The hotline by the addition of high-speed facsimile capability. The Soviet Union and the United States agreed formally to do this on July 17, 1984. According to the agreement, upgrades were to take place through use of Intelsat satellites and modems, facsimile machines, and computers. The facsimile terminals were operational by 1986. The teletype circuits were cut in 1988 after several years of testing and use proved

9600-476: The hotline in its 1964 national platform; it said the Kennedy administration had "sought accommodations with Communism without adequate safeguards and compensating gains for freedom. It has alienated proven allies by opening a 'hot line' first with a sworn enemy rather than with a proven friend, and in general pursued a risky path such as began at Munich a quarter of a century ago." The Moscow–Washington hotline

9728-456: The hotline. Since 2007 there has been a hotline between Beijing and Washington and also Beijing and Moscow. At the beginning of the Russian invasion of Ukraine , the United States and Russia created a deconfliction line to prevent miscalculations or escalation. In November 2022, an anonymous U.S. official told Reuters that the line had only been used once in the war. The official said that

9856-407: The key XMCKL would produce the plaintext hello , but she would also find that the key TQURI would produce the plaintext later , an equally plausible message: In fact, it is possible to "decrypt" out of the ciphertext any message whatsoever with the same number of characters, simply by using a different key, and there is no information in the ciphertext that will allow Eve to choose among

9984-555: The key tape could be completely random and that, if so, cryptanalysis would be more difficult. Together they invented the first one-time tape system. The next development was the paper pad system. Diplomats had long used codes and ciphers for confidentiality and to minimize telegraph costs. For the codes, words and phrases were converted to groups of numbers (typically 4 or 5 digits) using a dictionary-like codebook . For added security, secret numbers could be combined with (usually modular addition) each code group before transmission, with

10112-417: The key used during encryption. Asymmetric encryption algorithms depend on mathematical problems that are thought to be difficult to solve, such as integer factorization or the discrete logarithm . However, there is no proof that these problems are hard, and a mathematical breakthrough could make existing systems vulnerable to attack. Given perfect secrecy, in contrast to conventional symmetric encryption,

10240-420: The lack of which can pose a security threat in real-world systems. For example, an attacker who knows that the message contains "meet jane and me tomorrow at three thirty pm" can derive the corresponding codes of the pad directly from the two known elements (the encrypted text and the known plaintext). The attacker can then replace that text by any other text of exactly the same length, such as "three thirty meeting

10368-562: The largest university endowment in the world, valued at about $ 50.7 billion as of 2023. During the recession of 2007–2009 , it suffered significant losses that forced large budget cuts, in particular temporarily halting construction on the Allston Science Complex. The endowment has since recovered. About $ 2 billion of investment income is annually distributed to fund operations. Harvard's ability to fund its degree and financial aid programs depends on

10496-511: The late 19th century, Harvard University's graduate schools began admitting women in small numbers. In 1900, Harvard became a founding member of the Association of American Universities . For the first few decades of the 20th century, the Harvard student body was predominantly "old-stock, high-status Protestants , especially Episcopalians , Congregationalists , and Presbyterians ," according to sociologist and author Jerome Karabel . Over

10624-410: The line was used to communicate concerns about Russian military operations near Ukrainian infrastructure, but did not elaborate. The official said it was not used when a missile hit Poland . In numerous books, movies, video games, etc., the hotline between Washington and Moscow is represented by a red phone, although the real hotline has never been a telephone line. A hotline telephone was depicted in

10752-553: The main campus in Cambridge are the Law , Divinity (theology), Engineering and Applied Science , Design (architecture), Education , Kennedy (public policy), and Extension schools, and Harvard Radcliffe Institute in Radcliffe Yard. Harvard also has commercial real estate holdings in Cambridge. Harvard Business School , Harvard Innovation Labs , and many athletics facilities, including Harvard Stadium , are located on

10880-425: The message hello . Both Alice and Bob destroy the key sheet immediately after use, thus preventing reuse and an attack against the cipher. The KGB often issued its agents one-time pads printed on tiny sheets of flash paper, paper chemically converted to nitrocellulose , which burns almost instantly and leaves no ash. The classical one-time pad of espionage used actual pads of minuscule, easily concealed paper,

11008-621: The message were to indicate "an imminent disaster, such as an accidental nuclear strike", the MOLINK team would telephone the gist of the message to the Situation Room duty officer who would brief the president before a formal translation was complete. In 2007, the Moscow–Washington hotline was upgraded; a dedicated computer network links Moscow and Washington. The new system started operations on January 1, 2008. It continues to use

11136-411: The modern world, however, computers (such as those embedded in mobile phones ) are so ubiquitous that possessing a computer suitable for performing conventional encryption (for example, a phone that can run concealed cryptographic software) will usually not attract suspicion. A common use of the one-time pad in quantum cryptography is being used in association with quantum key distribution (QKD). QKD

11264-409: The next message". The material on the selected sheet is the key for this message. Each letter from the pad will be combined in a predetermined way with one letter of the message. (It is common, but not required, to assign each letter a numerical value , e.g., a is 0, b is 1, and so on.) In this example, the technique is to combine the key and the message using modular addition , not unlike

11392-408: The one-time pad has a property he termed perfect secrecy ; that is, the ciphertext C gives absolutely no additional information about the plaintext . This is because (intuitively), given a truly uniformly random key that is used only once, a ciphertext can be translated into any plaintext of the same length, and all are equally likely. Thus, the a priori probability of a plaintext message M

11520-405: The one-time pad is immune even to brute-force attacks. Trying all keys simply yields all plaintexts, all equally likely to be the actual plaintext. Even with a partially known plaintext, brute-force attacks cannot be used, since an attacker is unable to gain any information about the parts of the key needed to decrypt the rest of the message. The parts of the plaintext that are known will reveal only

11648-434: The pad using modular addition . The resulting ciphertext will be impossible to decrypt or break if the following four conditions are met: It has also been mathematically proven that any cipher with the property of perfect secrecy must use keys with effectively the same requirements as OTP keys. Digital versions of one-time pad ciphers have been used by nations for critical diplomatic and military communication , but

11776-401: The pad), while passing along unmeasured photons corresponding to the same bit of the key. Combining QKD with a one-time pad can also loosen the requirements for key reuse. In 1982, Bennett and Brassard showed that if a QKD protocol does not detect that an adversary was trying to intercept an exchanged key, then the key can safely be reused while preserving perfect secrecy. The one-time pad

11904-570: The parts of the key corresponding to them, and they correspond on a strictly one-to-one basis ; a uniformly random key's bits will be independent . Quantum cryptography and post-quantum cryptography involve studying the impact of quantum computers on information security . Quantum computers have been shown by Peter Shor and others to be much faster at solving some problems that the security of traditional asymmetric encryption algorithms depends on. The cryptographic algorithms that depend on these problems' difficulty would be rendered obsolete with

12032-536: The performance of its endowment; a poor performance in fiscal year 2016 forced a 4.4% cut in the number of graduate students funded by the Faculty of Arts and Sciences . Endowment income is critical, as only 22% of revenue is from students' tuition, fees, room, and board. Since the 1970s, several student-led campaigns have advocated divesting Harvard's endowment from controversial holdings, including investments in South Africa during apartheid , Sudan during

12160-462: The presidency. The red phone was also featured prominently in an advertisement from that year targeting President Ronald Reagan 's Strategic Defense Initiative . In the second ad, the ringing phone goes unanswered while the narrator says, "there will be no time to wake a president – computers will take control." Roy Spence revived the "red phone" idea in 2008 in an advertisement for candidate Hillary Clinton . Harvard Harvard University

12288-432: The pressure. Harvard is a large, highly residential research university offering 50 undergraduate majors, 134 graduate degrees, and 32 professional degrees. During the 2018–2019 academic year, Harvard granted 1,665 baccalaureate degrees, 1,013 graduate degrees, and 5,695 professional degrees. Harvard College , the four-year, full-time undergraduate program, has a liberal arts and sciences focus. To graduate in

12416-490: The primary and backup links took place daily. During the even hours, the US sent test messages to the Soviet Union. In the odd hours, the Soviet Union sent test messages to the US. The line was used during: On October 31, 2016, the Moscow–Washington hotline was used to reinforce Barack Obama's September warning that the U.S. would consider any interference on Election Day a grave matter. Another hotline-type mechanism for formal communications between Washington and Moscow are

12544-401: The problems of secure key distribution make them impractical for most applications. First described by Frank Miller in 1882, the one-time pad was re-invented in 1917. On July 22, 1919, U.S. Patent 1,310,719 was issued to Gilbert Vernam for the XOR operation used for the encryption of a one-time pad. Derived from his Vernam cipher , the system was a cipher that combined a message with

12672-466: The respective ciphertexts are given by: where ⊕ {\displaystyle \oplus } means XOR . If an attacker were to have both ciphertexts c 1 {\displaystyle c_{1}} and c 2 {\displaystyle c_{2}} , then simply taking the XOR of c 1 {\displaystyle c_{1}} and c 2 {\displaystyle c_{2}} yields

12800-477: The risk of compromise during transit (for example, a pickpocket swiping, copying and replacing the pad) is likely to be much greater in practice than the likelihood of compromise for a cipher such as AES . Finally, the effort needed to manage one-time pad key material scales very badly for large networks of communicants—the number of pads required goes up as the square of the number of users freely exchanging messages. For communication between only two persons, or

12928-435: The secret numbers being changed periodically (this was called superencryption ). In the early 1920s, three German cryptographers (Werner Kunze, Rudolf Schauffler, and Erich Langlotz), who were involved in breaking such systems, realized that they could never be broken if a separate randomly chosen additive number was used for every code group. They had duplicate paper pads printed with lines of random number groups. Each page had

13056-403: The sequence starts again at A. The ciphertext to be sent to Bob is thus EQNVZ . Bob uses the matching key page and the same process, but in reverse, to obtain the plaintext . Here the key is subtracted from the ciphertext, again using modular arithmetic: Similar to the above, if a number is negative, then 26 is added to make the number zero or higher. Thus Bob recovers Alice's plaintext,

13184-537: The sum of the messages' sizes equals the size of the pad. Quantum key distribution also proposes a solution to this problem, assuming fault-tolerant quantum computers. Distributing very long one-time pad keys is inconvenient and usually poses a significant security risk. The pad is essentially the encryption key, but unlike keys for modern ciphers, it must be extremely long and is far too difficult for humans to remember. Storage media such as thumb drives , DVD-Rs or personal digital audio players can be used to carry

13312-423: The surrounding Harvard Square neighborhood. The Yard houses several Harvard buildings, including four of the university's libraries, Houghton , Lamont , Pusey , and Widener . Also on Harvard Yard are Massachusetts Hall , built between 1718 and 1720 and the university's oldest still standing building, Memorial Church , and University Hall Harvard Yard and adjacent areas include the main academic buildings of

13440-471: The teletype messages using a shared one-time pad . Each country delivered keying tapes used to encode its messages via its embassy abroad. An advantage of the one-time pad was that neither country had to reveal more sensitive encryption methods to the other. In September 1971, Moscow and Washington decided to upgrade the system. The countries also agreed for the first time when the line should be used. Specifically, they agreed to notify each other immediately in

13568-460: The tenets of Puritanism. In 1650, the charter for Harvard Corporation , the college's governing body, was granted. From 1681 to 1701, Increase Mather , a Puritan clergyman, served as Harvard's sixth president . In 1708, John Leverett became Harvard's seventh president and the first president who was not also a clergyman. Harvard faculty and students largely supported the Patriot cause during

13696-498: The top universities in the world in each of these categories. Harvard students and alumni have also collectively won 10 Academy Awards and 110 Olympic medals , including 46 gold. Harvard was founded in 1636 during the colonial , pre- Revolutionary era by vote of the Great and General Court of Massachusetts Bay Colony , one of the original Thirteen Colonies of British America . Its first headmaster, Nathaniel Eaton , took office

13824-420: The two satellite links but a fiber optic cable replaced the old back-up cable. Commercial software is used for both chat and email: chat to coordinate operations, and email for actual messages. Transmission is nearly instantaneous. The first message transmitted over the hotline was on August 30, 1963. Washington sent Moscow the text: " THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG'S BACK 1234567890". The message

13952-498: The undergraduate college became accessible to striving middle class students from public schools; many more Jews and Catholics were admitted, but still few Blacks, Hispanics, or Asians versus the representation of these groups in the general U.S. population. Over the second half of the 20th century, however, the university became incrementally more diverse. Between 1971 and 1999, Harvard controlled undergraduate admission, instruction, and housing for Radcliffe's women; in 1999, Radcliffe

14080-400: The university's freshman dormitories , writing that, "We owe to the colored man the same opportunities for education that we do to the white man, but we do not owe to him to force him and the white into social relations that are not, or may not be, mutually congenial." Between 1933 and 1953, Harvard University was led by James B. Conant , the university's 23rd president, who reinvigorated

14208-428: The university's creative scholarship in an effort to guarantee Harvard's preeminence among the nation and world's emerging research institutions. Conant viewed higher education as a vehicle of opportunity for the talented rather than an entitlement for the wealthy, and devised programs to identify, recruit, and support talented youth. In 1945, under Conant's leadership, an influential 268-page report, General Education in

14336-531: The university's first professor for these language programs. From 1869 to 1909, Charles William Eliot , Harvard University's 21st president, decreased the historically favored position of Christianity in the curriculum, opening it to student self-direction. Though Eliot was an influential figure in the secularization of U.S. higher education, he was motivated primarily by Transcendentalist and Unitarian convictions influenced by William Ellery Channing , Ralph Waldo Emerson , and others, rather than secularism. In

14464-417: The use of a message authentication code can be used along with a one-time pad system to prevent such attacks, as can classical methods such as variable length padding and Russian copulation , but they all lack the perfect security the OTP itself has. Universal hashing provides a way to authenticate messages up to an arbitrary security bound (i.e., for any p > 0 , a large enough hash ensures that even

14592-507: The usual four years, undergraduates normally take four courses per semester. In most majors, an honors degree requires advanced coursework and a senior thesis. Though some introductory courses have large enrollments, the median class size is 12 students. The Faculty of Arts and Sciences , with an academic staff of 1,211 as of 2019, is the largest Harvard faculty, and has primary responsibility for instruction in Harvard College ,

14720-513: The various possible readings of the ciphertext. If the key is not truly random, it is possible to use statistical analysis to determine which of the plausible keys is the "least" random and therefore more likely to be the correct one. If a key is reused, it will noticeably be the only key that produces sensible plaintexts from both ciphertexts (the chances of some random incorrect key also producing two sensible plaintexts are very slim). One-time pads are " information-theoretically secure " in that

14848-472: The war. The university has ten academic faculties and a faculty attached to Harvard Radcliffe Institute . The Faculty of Arts and Sciences offers study in a wide range of undergraduate and graduate academic disciplines , and other faculties offer graduate degrees, including professional degrees. Harvard has three campuses: the main campus, a 209-acre (85 ha) in Cambridge centered on Harvard Yard ; an adjoining campus immediately across Charles River in

14976-473: The war. A few British one-time tape cipher machines include the Rockex and Noreen . The German Stasi Sprach Machine was also capable of using one time tape that East Germany, Russia, and even Cuba used to send encrypted messages to their agents. The World War II voice scrambler SIGSALY was also a form of one-time system. It added noise to the signal at one end and removed it at the other end. The noise

15104-464: Was appointed interim president. In August 2024, the university announced that Garber would be appointed Harvard's 31st president through the end of the 2026–27 academic year. The 209-acre (85 ha) main campus of Harvard University is centered on Harvard Yard , colloquially known as "the Yard," in Cambridge, Massachusetts , about 3 miles (5 km) west-northwest of downtown Boston , and extending to

15232-747: Was arrested and convicted in New York City in the 1950s, and the 'Krogers' (i.e., Morris and Lona Cohen ), who were arrested and convicted of espionage in the United Kingdom in the early 1960s. Both were found with physical one-time pads in their possession. A number of nations have used one-time pad systems for their sensitive traffic. Leo Marks reports that the British Special Operations Executive used one-time pads in World War II to encode traffic between its offices. One-time pads for use with its overseas agents were introduced late in

15360-477: Was distributed as a pad of paper, allowing the current top sheet to be torn off and destroyed after use. For concealment the pad was sometimes so small that a powerful magnifying glass was required to use it. The KGB used pads of such size that they could fit in the palm of a hand, or in a walnut shell. To increase security, one-time pads were sometimes printed onto sheets of highly flammable nitrocellulose , so that they could easily be burned after use. There

15488-404: Was distributed to the channel ends in the form of large shellac records that were manufactured in unique pairs. There were both starting synchronization and longer-term phase drift problems that arose and had to be solved before the system could be used. The hotline between Moscow and Washington D.C. , established in 1963 after the 1962 Cuban Missile Crisis , used teleprinters protected by

15616-479: Was electrical. In 1917, Gilbert Vernam (of AT&T Corporation ) invented and later patented in 1919 ( U.S. patent 1,310,719 ) a cipher based on teleprinter technology. Each character in a message was electrically combined with a character on a punched paper tape key. Joseph Mauborgne (then a captain in the U.S. Army and later chief of the Signal Corps ) recognized that the character sequence on

15744-427: Was fluent in Russian and well-briefed on world affairs was translator. The hotline was tested hourly. U.S. test messages included excerpts of William Shakespeare , Mark Twain , encyclopedias , and a first-aid manual ; Soviet tests included passages from the works of Anton Chekhov . MOLINK staffers took special care not to include innuendo or literary imagery that could be misinterpreted, such as passages from Winnie

15872-458: Was formally merged into Harvard University. On July 1, 2007, Drew Gilpin Faust , dean of Harvard Radcliffe Institute , was appointed Harvard's 28th and the university's first female president. On July 1, 2018, Faust retired and joined the board of Goldman Sachs , and Lawrence Bacow became Harvard's 29th president . In February 2023, approximately 6,000 Harvard workers attempted to organize

16000-578: Was intended for text only; speech might be misinterpreted. Leaders wrote in their native language and messages were translated at the receiving end. The first generation of the hotline used two full-time duplex telegraph circuits. The primary circuit was routed from Washington, D.C. via London , Copenhagen , Stockholm and Helsinki to Moscow . TAT-1 , the first submarine transatlantic telephone cable carried messages from Washington to London. A secondary radio line for back-up and service messages linked Washington and Moscow via Tangier . This network

16128-459: Was needed as they were used up fairly quickly. One problem with the system was that it could not be used for secure data storage. Later Vula added a stream cipher keyed by book codes to solve this problem. A related notion is the one-time code —a signal, used only once; e.g., "Alpha" for "mission completed", "Bravo" for "mission failed" or even "Torch" for " Allied invasion of French Northern Africa " cannot be "decrypted" in any reasonable sense of

16256-598: Was originally built by Harris Corporation . In July 1963 the United States sent four sets of teleprinters with the Latin alphabet to Moscow for the terminal there. A month later the Soviet equipment, four sets of East German teleprinters with the Cyrillic alphabet made by Siemens , arrived in Washington. The hotline started operations on August 30, 1963. A Japanese-built device called Electronic Teleprinter Cryptographic Regenerative Repeater Mixer II (ETCRRM II) encrypted

16384-458: Was sent in all capital letters, since the equipment did not support lowercase. Later, during testing, the Russian translators sent a message asking their American counterparts, "What does it mean when your people say 'The quick brown fox jumped over the lazy dog'?" The primary link was accidentally cut several times, for example near Copenhagen by a Danish bulldozer operator, and by a Finnish farmer who ploughed it up once. Regular testing of both

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