Cryptocurrencies use decentralized control as opposed to centralized digital currency and central banking systems. The decentralized control of each cryptocurrency works through distributed ledger technology, typically a blockchain, that serves as a public financial transaction database. Bitcoin, first released as open-source software in 2009, is generally considered the first decentralized cryptocurrency. Since the release of bitcoin, over 4,000 altcoins (alternative variants of bitcoin, or other cryptocurrencies) have been created. In 1983, the American cryptographer David Chaum conceived an anonymous cryptographic electronic money called ecash.


P2Ppeer to peerpeer-to-peer network
Bitcoin and alternatives such as Ether, Nxt and Peercoin are peer-to-peer-based digital cryptocurrencies. Dalesa, a peer-to-peer web cache for LANs (based on IP multicasting). FAROO, a peer-to-peer web search engine. Filecoin is an open source, public, cryptocurrency and digital payment system intended to be a blockchain-based cooperative digital storage and data retrieval method. I2P, an overlay network used to browse the Internet anonymously. Infinit is an unlimited and encrypted peer to peer file sharing application for digital artists written in C++.

Proof-of-work system

proof-of-workproof of workreusable proof of work
In 2009, the Bitcoin network went online. Bitcoin is a proof-of-work cryptocurrency that, like Finney's RPoW, is also based on the Hashcash PoW. But in Bitcoin double-spend protection is provided by a decentralized P2P protocol for tracking transfers of coins, rather than the hardware trusted computing function used by RPoW. Bitcoin has better trustworthiness because it is protected by computation. Bitcoins are "mined" using the Hashcash proof-of-work function by individual miners and verified by the decentralized nodes in the P2P bitcoin network. The difficulty is periodically adjusted to keep the block time around a target time.


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 synonymous with encryption, the conversion of information from a readable state to apparent nonsense. The originator of an encrypted message shares the decoding technique only with intended recipients to preclude access from adversaries. The cryptography literature often uses the names Alice ("A") for the sender, Bob ("B") for the intended recipient, and Eve ("eavesdropper") for the adversary.


Brian Armstrong
Coinbase is a digital currency exchange headquartered in San Francisco, California. They broker exchanges of Bitcoin, Bitcoin Cash, Ethereum, Ethereum Classic, and Litecoin with fiat currencies in approximately 32 countries, and bitcoin transactions and storage in 190 countries worldwide. Coinbase was founded in June 2012 by Brian Armstrong and Fred Ehrsam. co-founder Ben Reeves was part of the original founding team but later parted ways with Armstrong due to a difference in how the Coinbase wallet should operate. The remaining founding team enrolled in the Summer 2012 Y Combinator startup incubator program.


By 1990, in the United States all money transferred between its central bank and commercial banks was in electronic form. By the 2000s most money existed as digital currency in bank databases. In 2012, by number of transaction, 20 to 58 percent of transactions were electronic (dependant on country). Non-national digital currencies were developed in the early 2000s. In particular, Flooz and Beenz had gained momentum before the Dot-com bubble. Not much innovation occurred until the conception of Bitcoin in 2009, which introduced the concept of a cryptocurrency – a decentralised trustless currency.

History of money

monetary historyabandonmentan international currency of the early ages
By 1990, in the United States all money transferred between its central bank and commercial banks was in electronic form. By the 2000s most money existed as digital currency in banks databases. In 2012, by number of transaction, 20 to 58 percent of transactions were electronic (dependant on country). In 2008, Bitcoin was proposed by an unknown author/s under the pseudonym of Satoshi Nakamoto, it was implemented the same year. Its use of cryptography allowed the currency to have a trustless, fungible and tamper resistant distributed ledger called a blockchain. It became the first widely used decentralized, peer-to-peer, cryptocurrency.


double spending51% attack51% attacks
Decentralized currencies that rely on blockchain are vulnerable to the 51% attack, in which a malicious actor can rewrite the ledger if they control enough of the computational work being done.

Bitcoin Core

Bitcoin Core is free and open-source software that serves as a bitcoin node (the set of which form the bitcoin network) and provides a bitcoin wallet which fully verifies payments. It is considered to be bitcoin's reference implementation and is the most used implementation by a large margin. Initially, the software was published by Satoshi Nakamoto under the name "Bitcoin", and later renamed to "Bitcoin Core" to distinguish it from the network. For this reason, it is also known as the Satoshi client., Bitcoin Core repositories are maintained by a team of maintainers, with Wladimir J. van der Laan leading the release process.

List of cryptocurrencies

SHA-256 crypto currencies
By market capitalization, Bitcoin is currently (December 15, 2018) the largest blockchain network, followed by Ripple, Ethereum and Tether. As of 15 December 2018, total cryptocurrencies market capitalization is $100bn and larger than GDP of 127 countries. Below are some notable cryptocurrencies: *List of digital currencies


EtherETHETH blockchain
Bitcoin transactions usually have fees specified in satoshis per byte. Transaction fees are generally considerably lower for ether than for Bitcoin. In December 2017, the median transaction fee for ether corresponded to $0.33, while for bitcoin it corresponded to $23. Ethereum uses an account system where values in Wei are debited from accounts and credited to another, as opposed to Bitcoin's UTXO system, which is more analogous to spending cash and receiving change in return. J. P. Morgan Chase is developing a permissioned-variant of Ethereum blockchain dubbed "Quorum". It's designed to toe the line between private and public in the realm of shuffling derivatives and payments.


onlinethe Internetweb
Compared to printed media, books, encyclopedias and traditional libraries, the World Wide Web has enabled the decentralization of information on a large scale. The Web is therefore a global set of documents, images and other resources, logically interrelated by hyperlinks and referenced with Uniform Resource Identifiers (URIs). URIs symbolically identify services, servers, and other databases, and the documents and resources that they can provide. Hypertext Transfer Protocol (HTTP) is the main access protocol of the World Wide Web. Web services also use HTTP to allow software systems to communicate in order to share and exchange business logic and data.


eGoldDouglas Jackson
While PayPal has done a better job of addressing abuse than e-gold did, they now contend with the same kind of Internet fraud that took down e-gold. Financial cryptographers have observed that Bitcoin has repeated the same fundamental errors that e-gold made, and that despite its decentralized nature the cyber crime-wave might bring Bitcoin to a similar ending. According to GoldMoney's website, BitGold announced the acquisition of GoldMoney on May 22, 2015. Bitcoin. Digital currency. Digital currency exchanger. Gold as an investment. Liberty Reserve. PayPal. Private currency. WebMoney.

Mining pool

miners pool resourcesmining operationpool
Digital currency exchanger. Electronic money. Pooled mining in Bitcoin Wiki. An estimation of hashrate distribution amongst the largest mining pools.

Financial transaction

transactiontransactionsfinancial transactions
As fixed currencies were gradually replaced by floating currencies during the 20th century, and as the recent development of computer networks made electronic money possible, financial transactions have rapidly increased in speed and complexity. In 1997, 1.3 billion US dollars were exchanged per day on the foreign exchange market, roughly 475 billion US dollars annually. The world financial transactions have jumped from 1.1 quadrillion US dollars in 2002 to 2.2 quadrillion US dollars in 2008. 95% of this is speculation. A financial transaction always involves one or more financial asset.

Privacy and blockchain

Firstly, private keys are used to access funds and personal wallets on the blockchain. Private keys also add a layer of identity authentication. When an individual wishes to send money to another user, they must provide a digital signature (which is produced only when provided with the particular private key). This process protects against potential hackers that aim to pose as certain individuals and use the said-individuals funds. As previously stated, blockchain technology arose from the creation of Bitcoin. In 2008, a pseudonymous Satoshi Nakamoto released a paper describing the technology behind the technology.

List of highest funded crowdfunding projects

highest funded film campaign on Indiegogohighest-funded crowdfunding projects106th most crowdfunded project of all time
This is an incomplete list of the highest-funded crowdfunding projects (including projects which failed to achieve funding).

History of bitcoin

History of Virtual Cryptobanking with BitCoin
On 1 August 2017 bitcoin split into two derivative digital currencies, the bitcoin (BTC) chain with 1 MB blocksize limit and the Bitcoin Cash (BCH) chain with 8 MB blocksize limit. The split has been called the Bitcoin Cash hard fork. On 6 December 2017 the software marketplace Steam announced that it would no longer accept bitcoin as payment for its products, citing slow transactions speeds, price volatility, and high fees for transactions. On 22 January 2018, South Korea brought in a regulation that requires all the bitcoin traders to reveal their identity, thus putting a ban on anonymous trading of bitcoins.

List of people in blockchain technology

A few of these people pre-date the invention of this technology; they are now regarded as people in blockchain technology because their work can be seen as leading to the invention of this technology. * Wences Casares, CEO of Xapo * Wei Dai, creator of b-money; inspired the creation of Bitcoin by Satoshi Nakamoto * Hal Finney, the recipient of the first Bitcoin transaction * Tony Gallippi, founder of BitPay, a global bitcoin payment service provider headquartered in Atlanta, Georgia * Blythe Masters, CEO of Digital Asset Holdings * Satoshi Nakamoto, the name used by the unknown person or people who designed bitcoin and created its original reference implementation * Changpeng Zhao, founder of

In February 2014, Apple Inc. removed the Blockchain app from the iOS App Store, prompting a harsh response from Blockchain and public outcry in the bitcoin community, most notably within the Reddit community. In July 2014, Apple reinstated the app. In October 2014, closed a $30.5 million fundraising round from Lightspeed Venture Partners and Mosaic Ventures, which was the biggest round of financing in the digital currency sector at that time.

Darknet market

darknet marketsdarknet drug marketsblack market passwords
Later that month, the long-lived Outlaw market closed down citing a major bitcoin cryptocurrency wallet theft; however, speculation remained that it was an exit scam. In July 2017 the markets experienced their largest disruptions since Operations Onymous, when Operation Bayonet culminated in coordinated multinational seizures of both the Hansa and leading AlphaBay markets, sparking worldwide law enforcement investigations. The seizures brought in lots of traffic to other markets making TradeRoute and Dream Market the most popular markets at the time. In January 2018, Dream Market added Bitcoin Cash as a payment option.

Stellar (payment network)

StellarStellar LumenStellar Network
Stellar is an open-source, decentralized protocol for digital currency to fiat currency transfers which allows cross-border transactions between any pair of currencies. The Stellar protocol is supported by a nonprofit, the Stellar Development Foundation. In 2014, Jed McCaleb, founder of Mt. Gox and co-founder of Ripple, launched the network system Stellar with former lawyer Joyce Kim. Before the official launch, McCaleb formed a website called "Secret Bitcoin Project" seeking alpha testers. The nonprofit Stellar Development Foundation was created in collaboration with Stripe CEO Patrick Collison and the project officially launched that July.

Daniel Larimer

His interest in blockchains began in 2009, in the early days of Bitcoin. Larimer developed the blockchain technology Graphene, which powers BitShares and the Steem token cryptocurrency. In 2013, Larimer started BitShares. BitShares were originally named ProtoShares and intended to function as shares of virtual companies. BitShares has since been described as a cryptocurrency platform, a digital currency, or a digital exchange. It is organized as a decentralized autonomous organization (DAO). In 2016 Larimer left BitShares to found Steemit, a social network which uses blockchain technology to reward users. After founding Steemit, Larimer was CTO of the platform until March 2017.

Cryptocurrency exchange

bitcoin exchangeexchangedigital currency exchange
Bitcoin. Digital currency. Digital gold currency. List of Bitcoin companies.