Trusted timestamping

timestamptimestampedDecentralized timestamping
With the advent of cryptocurrencies like bitcoin, it has become possible to securely timestamp information in a decentralized and tamper-proof manner. Digital data can be hashed and the hash can be incorporated into a transaction stored in the blockchain, which serves as a secure proof of the exact time at which that data existed. The proof is due to a tremendous amount of computational effort performed after the hash was submitted to the blockchain. Tampering with the timestamp would require more computational resources than the rest of the network combined, and cannot be done unnoticed.

Kraken (company)

KrakenKraken cryptocurrency exchangeKraken exchange
In August Kraken listed Bitcoin Cash a hard-fork of Bitcoin with all clients that held bitcoin before the fork receiving an equal amount of Bitcoin Cash. In December it has been reported that Kraken was registering up to 50,000 new users a day. In April 2018, Kraken announced to shut its services in Japan, after operating since October 2014, by the end of June due to the rising costs of doing business there. Main article: Bankruptcy; stolen bitcoin In November 2014, Nobuaki Kobayashi, the court-appointed bankruptcy trustee overseeing the Mt.

Distributed ledger

distributed ledger technologyDistributed Ledger Technology (DLT)
One form of distributed ledger design is the blockchain system, which can be either public or private. The distributed ledger database is spread across several nodes (devices) on a peer-to-peer network, where each replicates and saves an identical copy of the ledger and updates itself independently. The primary advantage is the lack of central authority. When a ledger update happens, each node constructs the new transaction, and then the nodes vote by consensus algorithm on which copy is correct. Once a consensus has been determined, all the other nodes update themselves with the new, correct copy of the ledger. Security is accomplished through cryptographic keys and signatures.

Liberty Reserve

It was a member of the Global Digital Currency Association. Liberty employees were required to sign a confidentiality agreement to "maintain in strict confidentiality all information" about the company, including "administrative affairs, operations and financial details" for 15 years after leaving the company. Additionally they were required to notify management if issued a warrant to reveal such information. From 2002 to 2006, United States businessmen Arthur Budovsky and Vladimir Kats ran a digital currency exchange service known as Gold Age. In July 2006, the duo were indicted on charges of operating an illegal financial business, a felony.


In December 2013, PayPal acquired Braintree for $800 million. Prior to October 2015, Venmo prohibited merchants from accepting Venmo payments. On January 27, 2016, PayPal announced that Venmo was working with select merchants who would accept Venmo as payment. Initial launch partners included Munchery and Gametime. All merchants that accept PayPal can now accept Venmo.

Bitcoin Foundation

In November 2013, Patrick Murck, general counsel of the foundation, testified before a United States Senate committee convened to assess digital currencies, at which the reception of bitcoin by lawmakers was generally positive. In January 2014 the foundation's vice-chairman, Charlie Shrem, was arrested for aiding and abetting the operation of an unlicensed money-transmitting business related to his role in assisting agents of the online marketplace Silk Road; he resigned later that month and plead guilty in September 2014. In February 2014 Mark Karpeles, then CEO of the Mt. Gox exchange, resigned from the board after Mt.

Elon Musk

ElonMuskas early as 2021
One year later, the company merged with Confinity, which had a money-transfer service called PayPal. The merged company focused on the PayPal service and was renamed PayPal in 2001. PayPal's early growth was driven mainly by a viral marketing campaign where new customers were recruited when they received money through the service. Musk was ousted in October 2000 from his role as CEO (although he remained on the board) due to disagreements with other company leadership, notably over his desire to move PayPal's Unix-based infrastructure to Microsoft Windows. In October 2002, PayPal was acquired by eBay for US$1.5 billion in stock, of which Musk received US$165million.

Western Union

Western Union Telegraph CompanyWestern Union TelegraphWestern Union Company
Amman executed a strategy of redirecting Western Union from being an asset-based provider of communications services, with a money transfer business as a large but less important part of the business, into being a provider of consumer-based money transfer financial services. In so doing, Mr. Amman ran the company as two separate companies. One business consisted of the money transfer business, which was funded and operated to take advantage of the significant growth opportunity. The second unit consisted of all the non-strategic communications assets such as the long-distance analog voice network, satellite business and undersea cable assets. In the 3-year period through 1990 Mr.

Fork (blockchain)

hard forkforkfork referring to a blockchain
In cryptocurrencies, a fork is defined variously as Forks are related to the fact that different parties need to use common rules to maintain the history of the blockchain. Forks (in the sense of protocol changes) have been used in order to add new features to a blockchain, to reverse the effects of hacking or catastrophic bugs on a blockchain as was the case with the bitcoin fork on 6 August 2010 or the fork between Ethereum and Ethereum Classic. Notably, blockchain forks have been widely discussed in the context of the bitcoin scalability problem. Forks can be classified as accidental or intentional. Accidental fork happens when two or more miners find a block at nearly the same time.

Adam Back

Back, Adam
Today he is CEO of Blockstream, a company that seeks to further the development of bitcoin and blockchain technology. He has a computer science Ph.D. from University of Exeter. Data security. Information privacy.


paper moneybanknotespaper currency
Banknotes have increasingly been displaced by credit and debit cards and electronic money transfers. Some governments, such as Canada, are considering replacing paper notes and coins with digital currency. Sweden has begun implementing digital currency. Banknote collecting, or Notaphily, is a slowly growing area of numismatics. Although generally not as widespread as coin and stamp collecting, the hobby is slowly expanding. Prior to the 1990s, currency collecting was a relatively small adjunct to coin collecting, but currency auctions and greater public awareness of paper money have caused more interest in rare banknotes and consequently their increased value.


Facebook LiveFacebook, Inc.Facebook page
It received its first investment later that month from PayPal co-founder Peter Thiel. In 2005, the company dropped "the" from its name after purchasing the domain name for US$200,000. The domain belonged to AboutFace Corporation before the purchase. This website last appeared on April 8, 2005; from April 10, 2005, to August 4, 2005, this domain gave a 403 error. In May 2005, Accel Partners invested $12.7 million in Facebook, and Jim Breyer added $1 million of his own money. A high-school version of the site was launched in September 2005, which Zuckerberg called the next logical step. (At the time, high-school networks required an invitation to join.)

Ross Ulbricht

Dread Pirate RobertsRoss William Ulbrichtseizure
Silk Road was designed to use Tor and bitcoin. Tor is a protocol that encrypts data and routes Internet traffic through intermediary servers that anonymize IP addresses before reaching a final destination. By hosting his market as a Tor site, Ulbricht could conceal its IP address. Bitcoin is a cryptocurrency; while all bitcoin transactions are recorded in a log, the blockchain, users who avoid linking their identities to their online "wallets" can conduct transactions with considerable anonymity. Ulbricht used the Dread Pirate Roberts username for Silk Road. However, whether he was the only one to use that account is disputed.

Debit card

debit cardsdebitcard
This means that, among other advantages, the new system is suitable for electronic purchases without a delay of two to four days for bank-to-bank money transfers. Australia operates both electronic credit card transaction authorization and traditional EFTPOS debit card authorization systems, the difference between the two being that EFTPOS transactions are authorized by a personal identification number (PIN) while credit card transactions can additionally be authorized using a contactless payment mechanism.

Digital signature

digital signaturesdigitally signeddigitally sign
A scheme by Mihir Bellare and Gregory Neven may be used with Bitcoin. Signatures with efficient protocols - are signature schemes that facilitate efficient cryptographic protocols such as zero-knowledge proofs or secure computation. 21 CFR 11. X.509. Advanced electronic signature. Blind signature. Detached signature. Digital certificate. Digital signature in Estonia. Electronic lab notebook. Electronic signature. Electronic signatures and law. eSign (India). GNU Privacy Guard. Public key infrastructure. Server-based signatures. Probabilistic signature scheme. J. Katz and Y. Lindell, "Introduction to Modern Cryptography" (Chapman & Hall/CRC Press, 2007).

Bitcoin XT

Subsequently, Release H was published, which supported the November 2017 Bitcoin Cash protocol upgrade, followed by Release I, which supported the May 2018 Bitcoin Cash protocol upgrade. * Bitcoin XT on GitHub List of bitcoin forks. List of software forks. Bitcoin scalability problem.

Digital asset

digital assetsart assetassets
In 2015, Forbes and other sources characterized bitcoin as a digital asset. A digital asset management (DAM) system represents an intertwined structure incorporating both software and hardware and/or other services in order to manage, store, ingest, organise and retrieve digital assets. Digital asset management systems allow users to find and use content when they need it. Metadata is data about other data. Any structured information which's purpose is to define a specification of any form of data is referred to as metadata. "An item of metadata is a relationship that someone claims to exist between two entities".

Credit card

credit cardscreditcredit-card
Electronic money. Fair Credit Reporting Act. Identity theft. Interchange fee. International Card Manufacturers Association. Merchant account. Payment card. Point of sale. Reimbursement. Revolving account. Stored-value card. Klein, Lloyd. It's in the cards: consumer credit and the American experience (Greenwood Publishing Group, 1999); s the first comprehensive account of the development of consumer credit. Lee, Jinkook, and Kyoung‐Nan Kwon. "Consumers’ use of credit cards: Store credit card usage as an alternative payment and financing medium." Journal of Consumer Affairs 36.2 (2002): 239-262. Mandell, Lewis. The credit card industry: a history (Twayne Publishers, 1990). Manning, Robert D.


District Court, Western District of Kentucky, granted a temporary restraining order freezing Bitconnect's assets and "to disclose cryptocurrency wallet and trading account addresses, as well as the identities of anyone to whom Bitconnect has sent digital currencies within the last 90 days." On October 28, 2017, BitConnect held its first annual ceremony in Pattaya, Thailand. During the event, an investor named Carlos Matos from New York gave an enthusiastic presentation and testimonial about the website which led him becoming an internet meme. List of cryptocurrencies. OneCoin. USI Tech.

Virtual currency

virtual currenciesdigital tokensvirtual
Ecuador is the first country attempting a government run digital currency -no cryptocurrency; during the introductory phase from Christmas Eve 2014 until mid February 2015 people can open accounts and change passwords. At the end of February 2015 transactions of electronic money will be possible. Virtual currencies pose challenges for central banks, financial regulators, departments or ministries of finance, as well as fiscal authorities and statistical authorities.

P2P Foundation

Satoshi Nakamoto, the creator of bitcoin, released one of the first papers describing bitcoin on the p2p website. When Newsweek ran an article claiming Nakamoto is Dorian S. Nakamoto from Temple City, California, Nakamoto's user profile posted that he was not Dorian. The p2p foundation verified that the account was the same account that posted one of the first papers describing bitcoin. On September 2014, Nakamoto's p2p account was allegedly hacked and a post was made to his account that said his information was being sold on Darknet. The Chokepoint project was established in 2011 following the Internet blackouts in Egypt and Libya.

Mt. Gox

lost by Mt. GoxMtGox
In March 2018, the trustee Kobayashi said that enough BTC has been sold to cover the claims of creditors. * MtGox Co., Ltd. bankruptcy docket from the United States Courts Archive, Court Listener from Free Law Project Digital currency exchange. Bitfinex, which replaced Mt. Gox as the world's largest bitcoin exchange, lost $72 million in bitcoin in 2016.


Bitcointalk is a forum about bitcoin, and other cryptocurrencies. Satoshi Nakamoto created the bitcointalk forum, posted the first message in 2009 under the pseudonym satoshi. The commonly used cryptotrader misspelling "Hodl" originated from a 2013 bitcointalk forum post. The first bitcoin transaction took place at the forum, when software programmer Lazlo Hanyecz offered 10,000 bitcoins to purchase pizza, three days later a deal could be arranged to purchase two pizzas. Initial coin offerings are usually announced at the forum. A 2016 study by researchers from the University of New Mexico, and University of Tulsa, Oklahoma identified 1780 scams, based on forum reports.


Unspent transaction output

unspent outputs of transactionsunspent transaction outputs
In cryptocurrencies, an unspent transaction output (UTXO) is an output of a blockchain transaction that has not been spent, i.e. used as an input in a new transaction. Bitcoin is the most famous example of a cryptocurrency that uses the UTXO model. Outputs are a superset of UTXOs. Accordingly, UTXOs are a subset of the outputs superset. Bitcoin UTXO lifespans have been studied. In the case of a valid blockchain transaction, unspent outputs (and only unspent outputs) may be used to effect further transactions. The requirement that only unspent outputs may be used in further transactions is necessary to prevent double spending and fraud.