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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 consen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptocurrency
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, 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 transaction records, control the creation of additional coins, and verify the transfer of coin ownership. Despite their name, cryptocurrencies are not considered to be currencies in the traditional sense, and while varying treatments have been applied to them, including classification as commodities, securities, and currencies, cryptocurrencies are generally viewed as a disti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, 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 transaction records, control the creation of additional coins, and verify the transfer of coin ownership. Despite their name, cryptocurrencies are not considered to be currencies in the traditional sense, and while varying treatments have been applied to them, including classification as commodities, securities, and currencies, cryptocurrencies are generally viewed as a distinc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitcoin
Bitcoin ( abbreviation: BTC; sign: ₿) is a decentralized digital currency that can be transferred on the peer-to-peer bitcoin network. Bitcoin transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. The cryptocurrency was invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto. The currency began use in 2009, when its implementation was released as open-source software. The word "''bitcoin''" was defined in a white paper published on October 31, 2008. It is a compound of the words ''bit'' and ''coin''. The legality of bitcoin varies by region. Nine countries have fully banned bitcoin use, while a further fifteen have implicitly banned it. A few governments have used bitcoin in some capacity. El Salvador has adopted Bitcoin as legal tender, although use by merchants remains low. Ukraine has accepted cryptocurrency donations to fund the resistance to the 2022 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fork (blockchain)
In blockchain, a fork is defined variously as: * "what happens when a blockchain diverges into two potential paths forward" * "a change in protocol", or * a situation that "occurs when two or more blocks have the same block height" Forks are related to the fact that different parties need to use common rules to maintain the history of the blockchain. When parties are not in agreement, alternative chains may emerge. While most forks are short-lived some are permanent. Short-lived forks are due to the difficulty of reaching fast consensus in a distributed system. Whereas permanent forks (in the sense of protocol changes) have been used to add new features to a blockchain, they can also be used to reverse the effects of hacking such as the case with Ethereum and Ethereum Classic, or avert catastrophic bugs on a blockchain as was the case with the bitcoin fork on 6 August 2010. Blockchain forks have been widely discussed in the context of the bitcoin scalability problem. Types ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consensus Algorithm
A fundamental problem in distributed computing and multi-agent systems is to achieve overall system reliability in the presence of a number of faulty processes. This often requires coordinating processes to reach consensus, or agree on some data value that is needed during computation. Example applications of consensus include agreeing on what transactions to commit to a database in which order, state machine replication, and atomic broadcasts. Real-world applications often requiring consensus include cloud computing, clock synchronization, PageRank, opinion formation, smart power grids, state estimation, control of UAVs (and multiple robots/agents in general), load balancing, blockchain, and others. Problem description The consensus problem requires agreement among a number of processes (or agents) for a single data value. Some of the processes (agents) may fail or be unreliable in other ways, so consensus protocols must be fault tolerant or resilient. The processes must somehow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merkle Tree
In cryptography and computer science, a hash tree or Merkle tree is a tree in which every "leaf" (node) is labelled with the cryptographic hash of a data block, and every node that is not a leaf (called a ''branch'', ''inner node'', or ''inode'') is labelled with the cryptographic hash of the labels of its child nodes. A hash tree allows efficient and secure verification of the contents of a large data structure. A hash tree is a generalization of a hash list and a hash chain. Demonstrating that a leaf node is a part of a given binary hash tree requires computing a number of hashes proportional to the logarithm of the number of leaf nodes in the tree. Conversely, in a hash list, the number is proportional to the number of leaf nodes itself. A Merkle tree is therefore an efficient example of a cryptographic commitment scheme, in which the root of the tree is seen as a commitment and leaf nodes may be revealed and proven to be part of the original commitment. The concept of a hash ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stuart Haber
Stuart Haber is an American cryptographer and computer scientist, known for his contributions in cryptography and privacy-preserving technologies and widely recognized as the co-inventor of the blockchain. His 1991 paper "How to Time-Stamp a Digital Document”, co-authored with W. Scott Stornetta, won the 1992 Discover Award for Computer Software and is considered to be one of the most important papers in the development of cryptocurrencies. Education Haber studied at Harvard University, graduating magna cum laude in 1978 with a B.A. in Mathematics. Haber earned his PhD at Columbia University in 1987 under the advisement of Zvi Galil with a thesis titled ''Provably Secure Multi-party Cryptographic Computation: Techniques and Applications''. Career In 1987, Haber joined Bell Communications Research (Bellcore) as a research scientist. In 1989, Haber met W. Scott Stornetta, his future scientific partner and collaborator, when Stornetta joined Bellcore. In 1994, Haber and S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trusted Timestamping
Trusted timestamping is the process of securely keeping track of the creation and modification time of a document. Security here means that no one—not even the owner of the document—should be able to change it once it has been recorded provided that the timestamper's integrity is never compromised. The administrative aspect involves setting up a publicly available, trusted timestamp management infrastructure to collect, process and renew timestamps. History The idea of timestamping information is centuries old. For example, when Robert Hooke discovered Hooke's law in 1660, he did not want to publish it yet, but wanted to be able to claim priority. So he published the anagram ''ceiiinosssttuv'' and later published the translation ''ut tensio sic vis'' (Latin for "as is the extension, so is the force"). Similarly, Galileo first published his discovery of the phases of Venus in the anagram form. Sir Isaac Newton, in responding to questions from Leibniz in a letter in 167 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 and Zelle Zelle () is a United States–based digital payments network run by a private financial services company owned by the banks Bank of America, Truist, Capital One, JPMorgan Chase, PNC Bank, U.S. Bank, and Wells Fargo. The Zelle service enables .... 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
