{"id":120,"date":"2019-07-16T23:39:13","date_gmt":"2019-07-17T02:39:13","guid":{"rendered":"http:\/\/www.cin.ufpe.br\/~rsm4\/?page_id=120"},"modified":"2019-07-16T23:39:15","modified_gmt":"2019-07-17T02:39:15","slug":"blockchain","status":"publish","type":"page","link":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/blockchain\/","title":{"rendered":"Blockchain"},"content":{"rendered":"\n<p>A <strong>blockchain<\/strong>,<sup><a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-te20151031-1\" target=\"_blank\">[1]<\/a><a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-fortune20160515-2\" target=\"_blank\">[2]<\/a><a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-nyt20160521-3\" target=\"_blank\">[3]<\/a><\/sup> originally <strong>block chain<\/strong>,<sup><a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-primer-4\" target=\"_blank\">[4]<\/a><a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-obmh-5\" target=\"_blank\">[5]<\/a><\/sup> is a growing list of <a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Record_(computer_science)\" target=\"_blank\">records<\/a>, called <em>blocks<\/em>, that are linked using <a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Cryptography\" target=\"_blank\">cryptography<\/a>.<sup><a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-te20151031-1\" target=\"_blank\">[1]<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-cryptocurrencytech-6\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\">[6]<\/a><\/sup> Each block contains a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Cryptographic_hash_function\">cryptographic hash<\/a> of the previous block,<sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-cryptocurrencytech-6\">[6]<\/a><\/sup> a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Trusted_timestamping\">timestamp<\/a>, and transaction data (generally represented as a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Merkle_tree\">Merkle tree<\/a>). <\/p>\n\n\n\n<p>By design, a blockchain is resistant to modification of the data.\n It is &#8220;an open, distributed ledger that can record transactions between\n two parties efficiently and in a verifiable and permanent way&#8221;.<sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-hbr201701-7\">[7]<\/a><\/sup> For use as a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Distributed_ledger\">distributed ledger<\/a>, a blockchain is typically managed by a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Peer-to-peer\">peer-to-peer<\/a> network collectively adhering to a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Protocol_(communication)\">protocol<\/a>\n for inter-node communication and validating new blocks. Once recorded, \nthe data in any given block cannot be altered retroactively without \nalteration of all subsequent blocks, which requires consensus of the \nnetwork majority. Although blockchain records are not unalterable, \nblockchains may be considered <a href=\"https:\/\/en.wikipedia.org\/wiki\/Secure_by_design\">secure by design<\/a> and exemplify a distributed computing system with high <a href=\"https:\/\/en.wikipedia.org\/wiki\/Byzantine_fault_tolerance\">Byzantine fault tolerance<\/a>. <a href=\"https:\/\/en.wikipedia.org\/wiki\/Decentralized\">Decentralized<\/a> consensus has therefore been claimed with a blockchain.<sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-decapp-8\">[8]<\/a><\/sup>\n<\/p>\n\n\n\n<p>Blockchain was invented by a person (or group of people) using the name <a href=\"https:\/\/en.wikipedia.org\/wiki\/Satoshi_Nakamoto\">Satoshi Nakamoto<\/a> in 2008 to serve as the public transaction <a href=\"https:\/\/en.wikipedia.org\/wiki\/Ledger\">ledger<\/a> of the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Cryptocurrency\">cryptocurrency<\/a> <a href=\"https:\/\/en.wikipedia.org\/wiki\/Bitcoin\">bitcoin<\/a>.<sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-te20151031-1\">[1]<\/a><\/sup>  The identity of Satoshi Nakamoto is unknown. The invention of the  blockchain for bitcoin made it the first digital currency to solve the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Double-spending\">double-spending<\/a> problem without the need of a trusted authority or central <a href=\"https:\/\/en.wikipedia.org\/wiki\/Server_(computing)\">server<\/a>. The bitcoin design has inspired other applications,<sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-te20151031-1\">[1]<\/a><\/sup><sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-nyt20160521-3\">[3]<\/a><\/sup> and blockchains that are readable by the public are widely used by <a href=\"https:\/\/en.wikipedia.org\/wiki\/Cryptocurrencies\">cryptocurrencies<\/a>. Blockchain is considered a type of <a href=\"https:\/\/en.wikipedia.org\/wiki\/Payment_rail\">payment rail<\/a>.<sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-9\">[9]<\/a><\/sup> Private blockchains have been proposed for business use. Sources such as <em>Computerworld<\/em> called the marketing of such blockchains without a proper security model &#8220;<a href=\"https:\/\/en.wiktionary.org\/wiki\/snake_oil\">snake oil<\/a>&#8220;.<sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain#cite_note-cw20160905-10\">[10]<\/a><\/sup> <\/p>\n\n\n\n<p>Source: <a href=\"https:\/\/en.wikipedia.org\/wiki\/Blockchain\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"Wikipedia (opens in a new tab)\">Wikipedia<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A blockchain,[1][2][3] originally block chain,[4][5] is a growing list of records, called blocks, that are linked using cryptography.[1][6] Each block contains a cryptographic hash of the previous block,[6] a timestamp, and transaction data (generally represented as a Merkle tree). By design, a blockchain is resistant to modification of the data. It is &#8220;an open, distributed <a class=\"more-link\" href=\"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/blockchain\/\">&hellip; Continue lendo&hellip; &rarr;<\/a><\/p>\n","protected":false},"author":1,"featured_media":121,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"spay_email":""},"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/PaMH6m-1W","_links":{"self":[{"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/pages\/120"}],"collection":[{"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/comments?post=120"}],"version-history":[{"count":1,"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/pages\/120\/revisions"}],"predecessor-version":[{"id":122,"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/pages\/120\/revisions\/122"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/media\/121"}],"wp:attachment":[{"href":"https:\/\/www.cin.ufpe.br\/~rsm4\/index.php\/wp-json\/wp\/v2\/media?parent=120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}