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Key Stretching
In cryptography, key stretching techniques are used to make a possibly weak key, typically a password or passphrase, more secure against a brute-force attack by increasing the resources (time and possibly space) it takes to test each possible key. Passwords or passphrases created by humans are often short or predictable enough to allow password cracking, and key stretching is intended to make such attacks more difficult by complicating a basic step of trying a single password candidate. Key stretching also improves security in some real-world applications where the key length has been constrained, by mimicking a longer key length from the perspective of a brute-force attacker. There are several ways to perform key stretching. One way is to apply a cryptographic hash function or a block cipher repeatedly in a loop. For example, in applications where the key is used for a cipher, the key schedule in the cipher may be modified so that it takes a specific length of time to perform. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, 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, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security ( data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications. Cryptography prior to the modern age was effectively synonymo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moore's Law
Moore's law is the observation that the number of transistors in a dense integrated circuit (IC) doubles about every two years. Moore's law is an observation and projection of a historical trend. Rather than a law of physics, it is an empirical relationship linked to gains from experience in production. The observation is named after Gordon Moore, the co-founder of Fairchild Semiconductor and Intel (and former CEO of the latter), who in 1965 posited a doubling every year in the number of components per integrated circuit, and projected this rate of growth would continue for at least another decade. In 1975, looking forward to the next decade, he revised the forecast to doubling every two years, a compound annual growth rate (CAGR) of 41%. While Moore did not use empirical evidence in forecasting that the historical trend would continue, his prediction held since 1975 and has since become known as a "law". Moore's prediction has been used in the semiconductor industry to g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colin Percival
Colin A. Percival (born 1980) is a Canadian computer scientist and computer security researcher. He completed his undergraduate education at Simon Fraser University and a doctorate at the University of Oxford. While at university he joined the FreeBSD project, and achieved some notoriety for discovering a security weakness in Intel's hyper-threading technology. Besides his work in delta compression and the introduction of memory-hard functions, he is also known for developing the Tarsnap online backup service, which became his full-time job. Education Percival began taking mathematics courses at Simon Fraser University (SFU) at age 13, as a student at Burnaby Central Secondary School. He graduated from Burnaby Central and officially enrolled at SFU in 1998. At SFU he studied number theory under Peter Borwein, and competed in the William Lowell Putnam Mathematical Competition, placing in the top 15 in 1998 and as a Putnam Fellow (in the top six) in 1999. From 1998 to 2000 he ran t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scrypt
In cryptography, scrypt (pronounced "ess crypt") is a password-based key derivation function created by Colin Percival in March 2009, originally for the Tarsnap online backup service. The algorithm was specifically designed to make it costly to perform large-scale custom hardware attacks by requiring large amounts of memory. In 2016, the scrypt algorithm was published by IETF as RFC 7914. A simplified version of scrypt is used as a proof-of-work scheme by a number of cryptocurrencies, first implemented by an anonymous programmer called ArtForz in Tenebrix and followed by Fairbrix and Litecoin soon after. Introduction A password-based key derivation function (password-based KDF) is generally designed to be computationally intensive, so that it takes a relatively long time to compute (say on the order of several hundred milliseconds). Legitimate users only need to perform the function once per operation (e.g., authentication), and so the time required is negligible. However ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-11
The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, making it one of DEC's most successful product lines. The PDP-11 is considered by some experts to be the most popular minicomputer. The PDP-11 included a number of innovative features in its instruction set and additional general-purpose registers that made it much easier to program than earlier models in the PDP series. Further, the innovative Unibus system allowed external devices to be easily interfaced to the system using direct memory access, opening the system to a wide variety of peripherals. The PDP-11 replaced the PDP-8 in many real-time computing applications, although both product lines lived in parallel for more than 10 years. The ease of programming of the PDP-11 made it very popular for general-purpose computing uses also. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASCII
ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of technical limitations of computer systems at the time it was invented, ASCII has just 128 code points, of which only 95 are , which severely limited its scope. All modern computer systems instead use Unicode, which has millions of code points, but the first 128 of these are the same as the ASCII set. The Internet Assigned Numbers Authority (IANA) prefers the name US-ASCII for this character encoding. ASCII is one of the List of IEEE milestones, IEEE milestones. Overview ASCII was developed from telegraph code. Its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on the ASCII standard began in May 1961, with the first meeting of the American Standards Association's (ASA) (now the American Nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Encryption Standard
The Data Encryption Standard (DES ) is a symmetric-key algorithm for the encryption of digital data. Although its short key length of 56 bits makes it too insecure for modern applications, it has been highly influential in the advancement of cryptography. Developed in the early 1970s at IBM and based on an earlier design by Horst Feistel, the algorithm was submitted to the National Bureau of Standards (NBS) following the agency's invitation to propose a candidate for the protection of sensitive, unclassified electronic government data. In 1976, after consultation with the National Security Agency (NSA), the NBS selected a slightly modified version (strengthened against differential cryptanalysis, but weakened against brute-force attacks), which was published as an official Federal Information Processing Standard (FIPS) for the United States in 1977. The publication of an NSA-approved encryption standard led to its quick international adoption and widespread academic scrutiny. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley (Berkeley Software Distribution, BSD), Microsoft (Xenix), Sun Microsystems (SunOS/Solaris (operating system), Solaris), Hewlett-Packard, HP/Hewlett Packard Enterprise, HPE (HP-UX), and IBM (IBM AIX, AIX). In the early 1990s, AT&T sold its rights in Unix to Novell, which then sold the UNIX trademark to The Open Group, an industry consortium founded in 1996. The Open Group allows the use of the mark for certified operating systems that comply with the Single UNIX Specification (SUS). Unix systems are chara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Morris (cryptographer)
Robert H. Morris Sr. (July 25, 1932 – June 26, 2011) was an American cryptographer and computer scientist. __TOC__ Family and education Morris was born in Boston, Massachusetts. His parents were Walter W. Morris, a salesman, and Helen Kelly Morris, a homemaker. He received a bachelor's degree in mathematics from Harvard University in 1957 and a master's degree in applied mathematics from Harvard in 1958. He married Anne Farlow, and they had three children together: Robert Tappan Morris (author of the 1988 Morris worm), Meredith Morris, and Benjamin Morris. Bell Labs From 1960 until 1986, Morris was a researcher at Bell Labs and worked on Multics and later Unix. Together with Douglas McIlroy, he created M6 macro processor in FORTRAN IV, which was later ported to Unix. Using the TMG compiler-compiler, Morris, together with McIlroy, developed the early implementation of PL/I compiler called EPL for Multics project. The pair also contributed a version of runoff text-forma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cache (computing)
In computing, a cache ( ) is a hardware or software component that stores data so that future requests for that data can be served faster; the data stored in a cache might be the result of an earlier computation or a copy of data stored elsewhere. A ''cache hit'' occurs when the requested data can be found in a cache, while a ''cache miss'' occurs when it cannot. Cache hits are served by reading data from the cache, which is faster than recomputing a result or reading from a slower data store; thus, the more requests that can be served from the cache, the faster the system performs. To be cost-effective and to enable efficient use of data, caches must be relatively small. Nevertheless, caches have proven themselves in many areas of computing, because typical computer applications access data with a high degree of locality of reference. Such access patterns exhibit temporal locality, where data is requested that has been recently requested already, and spatial locality, where d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Bound Function
Memory bound refers to a situation in which the time to complete a given computational problem is decided primarily by the amount of free memory required to hold the working data. This is in contrast to algorithms that are compute-bound, where the number of elementary computation steps is the deciding factor. Memory and computation boundaries can sometimes be traded against each other, e.g. by saving and reusing preliminary results or using lookup tables. Memory-bound functions and memory functions Memory-bound functions and memory functions are related in that both involve extensive memory access, but a distinction exists between the two. Memory functions use a dynamic programming technique called memoization in order to relieve the inefficiency of recursion that might occur. It is based on the simple idea of calculating and storing solutions to subproblems so that the solutions can be reused later without recalculating the subproblems again. The best known example that takes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nvidia
Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to early-mid 2000s. Though unofficial, second letter capitalization of NVIDIA, i.e. nVidia, may be found within enthusiast communities and publications. ( ) is an American multinational technology company incorporated in Delaware and based in Santa Clara, California. It is a software and fabless company which designs graphics processing units (GPUs), application programming interface (APIs) for data science and high-performance computing as well as system on a chip units (SoCs) for the mobile computing and automotive market. Nvidia is a global leader in artificial intelligence hardware and software. Its professional line of GPUs are used in workstations for applications in such fields as architecture, engineering and construction, media ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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