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John Pollard (mathematician)
John M. Pollard (born 1941) is a British mathematician who has invented algorithms for the factorization of large numbers and for the calculation of discrete logarithms. His factorization algorithms include the rho, ''p'' − 1, and the first version of the special number field sieve, which has since been improved by others. His discrete logarithm algorithms include the rho algorithm for logarithms and the kangaroo algorithm. He received the RSA Award for Excellence in Mathematics RSA may refer to: Organizations Academia and education *Rabbinical Seminary of America, a yeshiva in New York City * Regional Science Association International (formerly the Regional Science Association), a US-based learned society * Renaissance .... External links John Pollard's web site Living people 20th-century British mathematicians 21st-century British mathematicians Number theorists Place of birth missing (living people) 1941 births {{UK-mathematician-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematical model, models, and mathematics#Calculus and analysis, change. History One of the earliest known mathematicians were Thales of Miletus (c. 624–c.546 BC); he has been hailed as the first true mathematician and the first known individual to whom a mathematical discovery has been attributed. He is credited with the first use of deductive reasoning applied to geometry, by deriving four corollaries to Thales' Theorem. The number of known mathematicians grew when Pythagoras of Samos (c. 582–c. 507 BC) established the Pythagoreans, Pythagorean School, whose doctrine it was that mathematics ruled the universe and whose motto was "All is number". It was the Pythagoreans who coined the term "mathematics", and with whom the study of mathemat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integer Factorization
In number theory, integer factorization is the decomposition of a composite number into a product of smaller integers. If these factors are further restricted to prime numbers, the process is called prime factorization. When the numbers are sufficiently large, no efficient non-quantum integer factorization algorithm is known. However, it has not been proven that such an algorithm does not exist. The presumed difficulty of this problem is important for the algorithms used in cryptography such as RSA public-key encryption and the RSA digital signature. Many areas of mathematics and computer science have been brought to bear on the problem, including elliptic curves, algebraic number theory, and quantum computing. In 2019, Fabrice Boudot, Pierrick Gaudry, Aurore Guillevic, Nadia Heninger, Emmanuel Thomé and Paul Zimmermann factored a 240-digit (795-bit) number ( RSA-240) utilizing approximately 900 core-years of computing power. The researchers estimated that a 1024- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discrete Logarithm
In mathematics, for given real numbers ''a'' and ''b'', the logarithm log''b'' ''a'' is a number ''x'' such that . Analogously, in any group ''G'', powers ''b''''k'' can be defined for all integers ''k'', and the discrete logarithm log''b'' ''a'' is an integer ''k'' such that . In number theory, the more commonly used term is index: we can write ''x'' = ind''r'' ''a'' (mod ''m'') (read "the index of ''a'' to the base ''r'' modulo ''m''") for ''r''''x'' ≡ ''a'' (mod ''m'') if ''r'' is a primitive root of ''m'' and gcd(''a'',''m'') = 1. Discrete logarithms are quickly computable in a few special cases. However, no efficient method is known for computing them in general. Several important algorithms in public-key cryptography, such as ElGamal base their security on the assumption that the discrete logarithm problem over carefully chosen groups has no efficient solution. Definition Let ''G'' be any group. Denote its group operation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollard's Rho Algorithm
Pollard's rho algorithm is an algorithm for integer factorization. It was invented by John Pollard in 1975. It uses only a small amount of space, and its expected running time is proportional to the square root of the smallest prime factor of the composite number being factorized. Core ideas The algorithm is used to factorize a number n = pq, where p is a non-trivial factor. A polynomial modulo n, called g(x) (e.g., g(x) = (x^2 + 1) \bmod n), is used to generate a pseudorandom sequence. It is important to note that g(x) must be a polynomial. A starting value, say 2, is chosen, and the sequence continues as x_1 = g(2), x_2 = g(g(2)), x_3 = g(g(g(2))), etc. The sequence is related to another sequence \. Since p is not known beforehand, this sequence cannot be explicitly computed in the algorithm. Yet, in it lies the core idea of the algorithm. Because the number of possible values for these sequences is finite, both the \ sequence, which is mod n, and \ sequence will eventually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollard's P − 1 Algorithm
Pollard's ''p'' − 1 algorithm is a number theoretic integer factorization algorithm, invented by John Pollard in 1974. It is a special-purpose algorithm, meaning that it is only suitable for integers with specific types of factors; it is the simplest example of an algebraic-group factorisation algorithm. The factors it finds are ones for which the number preceding the factor, ''p'' − 1, is powersmooth; the essential observation is that, by working in the multiplicative group modulo a composite number ''N'', we are also working in the multiplicative groups modulo all of ''Ns factors. The existence of this algorithm leads to the concept of safe primes, being primes for which ''p'' − 1 is two times a Sophie Germain prime ''q'' and thus minimally smooth. These primes are sometimes construed as "safe for cryptographic purposes", but they might be ''unsafe'' — in current recommendations for cryptographic strong primes (''e.g.'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Special Number Field Sieve
In number theory, a branch of mathematics, the special number field sieve (SNFS) is a special-purpose integer factorization algorithm. The general number field sieve (GNFS) was derived from it. The special number field sieve is efficient for integers of the form ''r''''e'' ± ''s'', where ''r'' and ''s'' are small (for instance Mersenne number In mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form for some integer . They are named after Marin Mersenne, a French Minim friar, who studied them in the early 17t ...s). Heuristically, its Computational complexity theory, complexity for factoring an integer n is of the form: :\exp\left(\left(1+o(1)\right)\left(\tfrac\log n\right)^\left(\log\log n\right)^\right)=L_n\left[1/3,(32/9)^\right] in Big O notation, O and L-notations. The SNFS has been used extensively by NFSNet (a volunteer distributed computing effort)NFS@Homeand others to factorise numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollard's Rho Algorithm For Logarithms
Pollard's rho algorithm for logarithms is an algorithm introduced by John Pollard in 1978 to solve the discrete logarithm problem, analogous to Pollard's rho algorithm to solve the integer factorization problem. The goal is to compute \gamma such that \alpha ^ \gamma = \beta, where \beta belongs to a cyclic group G generated by \alpha. The algorithm computes integers a, b, A, and B such that \alpha^a \beta^b = \alpha^A \beta^B. If the underlying group is cyclic of order n, by substituting \beta as a^ and noting that two powers are equal if and only if the exponents are equivalent modulo the order of the base, in this case modulo n, we get that \gamma is one of the solutions of the equation (B-b) \gamma = (a-A) \pmod n. Solutions to this equation are easily obtained using the extended Euclidean algorithm. To find the needed a, b, A, and B the algorithm uses Floyd's cycle-finding algorithm to find a cycle in the sequence x_i = \alpha^ \beta^, where the function f: x_i \maps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollard's Kangaroo Algorithm
In computational number theory and computational algebra, Pollard's kangaroo algorithm (also Pollard's lambda algorithm, see Naming below) is an algorithm for solving the discrete logarithm problem. The algorithm was introduced in 1978 by the number theorist J. M. Pollard, in the same paper as his better-known Pollard's rho algorithm for solving the same problem. Although Pollard described the application of his algorithm to the discrete logarithm problem in the multiplicative group of units modulo a prime ''p'', it is in fact a generic discrete logarithm algorithm—it will work in any finite cyclic group. Algorithm Suppose G is a finite cyclic group of order n which is generated by the element \alpha, and we seek to find the discrete logarithm x of the element \beta to the base \alpha. In other words, one seeks x \in Z_n such that \alpha^x = \beta. The lambda algorithm allows one to search for x in some interval ,\ldots,bsubset Z_n. One may search the entire range of poss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RSA Award For Excellence In Mathematics
RSA may refer to: Organizations Academia and education *Rabbinical Seminary of America, a yeshiva in New York City * Regional Science Association International (formerly the Regional Science Association), a US-based learned society * Renaissance Society of America, a scholarly organization based in New York City * Rhetoric Society of America, an academic organization for the study of rhetoric *Royal Scottish Academy, a Scottish institute of the Arts *Royal Society of Arts, formally the Royal Society for the encouragement of Arts, Manufactures and Commerce, a British institution Military *Redstone Arsenal, a United States Army post adjacent to Huntsville, Alabama * Royal New Zealand Returned and Services' Association, an organization for the welfare of veterans of New Zealand's military * Royal School of Artillery, a British Army training establishment for artillery warfare *Royal Signals Association, an organization for serving and retired members of the Royal Corps of Signals, of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Living People
Related categories * :Year of birth missing (living people) / :Year of birth unknown * :Date of birth missing (living people) / :Date of birth unknown * :Place of birth missing (living people) / :Place of birth unknown * :Year of death missing / :Year of death unknown * :Date of death missing / :Date of death unknown * :Place of death missing / :Place of death unknown * :Missing middle or first names See also * :Dead people * :Template:L, which generates this category or death years, and birth year and sort keys. : {{DEFAULTSORT:Living people 21st-century people People by status ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
21st-century British Mathematicians
The 1st century was the century spanning AD 1 (Roman numerals, I) through AD 100 (Roman numerals, C) according to the Julian calendar. It is often written as the or to distinguish it from the 1st century BC (or BCE) which preceded it. The 1st century is considered part of the Classical era, epoch, or History by period, historical period. The 1st century also saw the Christianity in the 1st century, appearance of Christianity. During this period, Europe, North Africa and the Near East fell under increasing domination by the Roman Empire, which continued expanding, most notably conquering Britain under the emperor Claudius (AD 43). The reforms introduced by Augustus during his long reign stabilized the empire after the turmoil of the previous century's civil wars. Later in the century the Julio-Claudian dynasty, which had been founded by Augustus, came to an end with the suicide of Nero in AD 68. There followed the famous Year of Four Emperors, a brief period of civil war and inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
