Block (blockchain)
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Block (blockchain)
A blockchain is a type of distributed ledger technology (DLT) that consists of growing lists of records, called ''blocks'', that are securely linked together using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data (generally represented as a Merkle tree, where data nodes are represented by leaves). The timestamp proves that the transaction data existed when the block was created. Since each block contains information about the previous block, they effectively form a ''chain'' (compare linked list data structure), with each additional block linking to the ones before it. Consequently, blockchain transactions are irreversible in that, once they are recorded, the data in any given block cannot be altered retroactively without altering all subsequent blocks. Blockchains are typically managed by a peer-to-peer (P2P) computer network for use as a public distributed ledger, where nodes collectively adhere to a consensus a ...
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Distributed Ledger
A distributed ledger (also called a shared ledger or distributed ledger technology or DLT) is the consensus of replicated, shared, and synchronized digital data that is geographically spread (distributed) across many sites, countries, or institutions. In contrast to a centralized database, a distributed ledger does not require a central administrator, and consequently does not have a single (central) point-of-failure. In general, a distributed ledger requires a peer-to-peer (P2P) computer network and consensus algorithms so that the ledger is reliably replicated across distributed computer nodes (servers, clients, etc.). The most common form of distributed ledger technology is the blockchain (commonly associated with the Bitcoin cryptocurrency), which can either be on a public or private network. Infrastructure for data management is a common barrier to implementing DLT. In some cases, where the distributed digital information functions as an accounting journal rather than an a ...
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Satoshi Nakamoto
Satoshi Nakamoto is the name used by the presumed pseudonymous person or persons who developed bitcoin, authored the bitcoin white paper, and created and deployed bitcoin's original reference implementation. As part of the implementation, Nakamoto also devised the first blockchain database. Nakamoto was active in the development of bitcoin up until December 2010. There has been widespread speculation about Satoshi Nakamoto's true identity, with a variety of people posited as the person or persons behind the name. Though Nakamoto's name is Japanese, and he stated in 2012 that he was a man living in Japan, most of the speculation has involved software and cryptography experts in the United States or Europe. Development of bitcoin Nakamoto stated that work on the writing of the code for Bitcoin began in 2007. On 18 August 2008, he or a colleague registered the domain name bitcoin.org, and created a web site at that address. On 31 October, Nakamoto published a white paper on the ...
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Hashcash
Hashcash is a proof-of-work system used to limit email spam and denial-of-service attacks, and more recently has become known for its use in bitcoin (and other cryptocurrencies) as part of the mining algorithm. Hashcash was proposed in 1997 by Adam Back and described more formally in Back's 2002 paper "Hashcash - A Denial of Service Counter-Measure". Background The idea "...to require a user to compute a moderately hard, but not intractable function..." was proposed by Cynthia Dwork and Moni Naor in their 1992 paper "Pricing via Processing or Combatting Junk Mail". How it works Hashcash is a cryptographic hash-based proof-of-work algorithm that requires a selectable amount of work to compute, but the proof can be verified efficiently. For email uses, a textual encoding of a hashcash stamp is added to the header of an email to prove the sender has expended a modest amount of CPU time calculating the stamp prior to sending the email. In other words, as the sender has taken a certain ...
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The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid digital subscribers. It also is a producer of popular podcasts such as '' The Daily''. Founded in 1851 by Henry Jarvis Raymond and George Jones, it was initially published by Raymond, Jones & Company. The ''Times'' has won 132 Pulitzer Prizes, the most of any newspaper, and has long been regarded as a national " newspaper of record". For print it is ranked 18th in the world by circulation and 3rd in the U.S. The paper is owned by the New York Times Company, which is publicly traded. It has been governed by the Sulzberger family since 1896, through a dual-class share structure after its shares became publicly traded. A. G. Sulzberger, the paper's publisher and the company's chairman, is the fifth generation of the family to head the pa ...
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David Chaum
David Lee Chaum (born 1955) is an American computer scientist, cryptographer, and inventor. He is known as a pioneer in cryptography and privacy-preserving technologies, and widely recognized as the inventor of digital cash. His 1982 dissertation "Computer Systems Established, Maintained, and Trusted by Mutually Suspicious Groups" is the first known proposal for a blockchain protocol. Complete with the code to implement the protocol, Chaum's dissertation proposed all but one element of the blockchain later detailed in the Bitcoin whitepaper. He has been referred to as "the father of online anonymity", and "the godfather of cryptocurrency". He is also known for developing ecash, an electronic cash application that aims to preserve a user's anonymity, and inventing many cryptographic protocols like the blind signature, mix networks and the Dining cryptographers protocol. In 1995 his company DigiCash created the first digital currency with eCash.Greenberg, Andy (2012). ''This M ...
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Snake Oil
Snake oil is a term used to describe deceptive marketing, health care fraud, or a scam. Similarly, "snake oil salesman" is a common expression used to describe someone who sells, promotes, or is a general proponent of some valueless or fraudulent cure, remedy, or solution. The term comes from the "snake oil" that used to be sold as a cure-all elixir for many kinds of physiological problems. Many 19th-century United States and 18th-century European entrepreneurs advertised and sold mineral oil (often mixed with various active and inactive household herbs, spices, drugs, and compounds, but containing no snake-derived substances whatsoever) as "snake oil liniment", making claims about its efficacy as a panacea. Patent medicines that claimed to be a panacea were extremely common from the 18th century until the 20th, particularly among vendors masking addictive drugs such as cocaine, amphetamine, alcohol, and opium-based concoctions or elixirs, to be sold at medicine shows as medic ...
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Payment Rail
A payment rail is a payment platform or a payment network that moves money from a payer to a payee. Either party could be a consumer or business, and both parties are able to move funds on the network. Credit card rails are the credit card payment system. Blockchain is considered a newer type of payment rail, as are centralized electronic payment systems such as PayPal, Venmo Venmo is an American mobile payment service founded in 2009 and owned by PayPal since 2013. Venmo was aimed at friends and family who wish to split bills, e.g. for movies, dinner, rent, or event tickets etc. Account holders can transfer funds t ... and Zelle. If the transferred funds are available immediately, a payment rail is referred to as a real-time rail. References {{finance-stub Payment systems Payment networks Banking technology Banking terms Payment clearing systems Banking in the United States ...
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Cryptocurrencies
A cryptocurrency, crypto-currency, or crypto is a digital currency designed to work as a medium of exchange through a computer network that is not reliant on any central authority, such as a government or bank A bank is a financial institution that accepts deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital markets. Because ..., to uphold or maintain it. It is a decentralized system for verifying that the parties to a transaction have the money they claim to have, eliminating the need for traditional intermediaries, such as banks, when funds are being transferred between two entities. Individual coin ownership records are stored in a digital ledger, which is a computerized database using strong cryptography to secure E-commerce, transaction records, control the creation of additional coins, and verify the transfer of coin ownership. Despite the ...
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Server (computing)
In computing, a server is a piece of computer hardware or software (computer program) that provides functionality for other programs or devices, called " clients". This architecture is called the client–server model. Servers can provide various functionalities, often called "services", such as sharing data or resources among multiple clients, or performing computation for a client. A single server can serve multiple clients, and a single client can use multiple servers. A client process may run on the same device or may connect over a network to a server on a different device. Typical servers are database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. Client–server systems are usually most frequently implemented by (and often identified with) the request–response model: a client sends a request to the server, which performs some action and sends a response back to the client, typically with a result or acknowledg ...
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Double-spending
Double-spending is a fundamental flaw in a digital cash protocol in which the same single digital token can be spent more than once. Due to the nature of information space, in comparison to physical space (as in: valuable physical resources), a digital token (like a file) is inherently almost infinitely duplicable or falsifiable, leading to ownership of said token itself being undefinable unless declared so by a chosen authority. As with counterfeit money, such double-spending leads to inflation by creating a new amount of copied currency that did not previously exist. Like all increasingly abundant resources, this devalues the currency relative to other monetary units or goods and diminishes user trust as well as the circulation and retention of the currency. Fundamental cryptographic techniques to prevent double-spending, while preserving anonymity in a transaction, are the introduction of an authority (and hence centralization) for blind signatures and, particularly in offline ...
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Dave Bayer
David Allen Bayer (born November 29, 1955) is an American mathematician known for his contributions in algebra and symbolic computation and for his consulting work in the movie industry. He is a professor of mathematics at Barnard College, Columbia University. Education and career Bayer was educated at Swarthmore College as an undergraduate, where he attended a course on combinatorial algorithms given by Herbert Wilf. During that semester, Bayer related several original ideas to Wilf on the subject. These contributions were later incorporated into the second edition of Wilf and Albert Nijenhuis' influential book ''Combinatorial Algorithms'', with a detailed acknowledgement by its authors. Bayer subsequently earned his Ph.D. at Harvard University in 1982 under the direction of Heisuke Hironaka with a dissertation entitled ''The Division Algorithm and the Hilbert Scheme''. He joined Columbia University thereafter. Bayer is the son of Bryce Bayer, the inventor of the Bayer filter. C ...
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