The bitcoin network is a peer-to-peer payment network that operates on a cryptographic protocol. Users send and receive bitcoins, the units of currency, by broadcasting digitally signed messages to the network using bitcoin cryptocurrency wallet software. Transactions are recorded into a distributed, replicated public database known as the blockchain, with consensus achieved by a proof-of-work system called mining. Satoshi Nakamoto, the designer of bitcoin claimed that design and coding of bitcoin began in 2007. The project was released in 2009 as open source software. The network requires the minimal structure to share transactions. An ad hoc decentralized network of volunteers is sufficient. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will. Upon reconnection, a node downloads and verifies new blocks from other nodes to complete its local copy of the blockchain. A bitcoin is defined by a sequence of digitally signed transactions that began with the bitcoin's creation, as a block reward. The owner of a bitcoin transfers it by digitally signing it over to the next owner using a bitcoin transaction, much like endorsing a traditional bank check. A payee can examine each previous transaction to verify the chain of ownership. Unlike traditional check endorsements, bitcoin transactions are irreversible, which eliminates the risk of chargeback fraud. Although it is possible to handle bitcoins individually, it would be unwieldy to require a separate transaction for every bitcoin in a transaction. Transactions are therefore allowed to contain multiple inputs and outputs, allowing bitcoins to be split and combined. Common transactions will have either a single input from a larger previous transaction or multiple inputs combining smaller amounts, and one or two outputs: one for the payment, and one returning the change, if any, to the sender. Any difference between the total input and output amounts of a transaction goes to miners as a transaction fee. In 2013, Mark Gimein estimated electricity consumption to be about 40.9 megawatts (982 megawatt-hours a day). In 2014, Hass McCook estimated 80.7 megawatts (80,666 kW). As of 2015, The Economist estimated that even if all miners used modern facilities, the combined electricity consumption would be 166.7 megawatts (1.46 terawatt-hours per year). To lower the costs, bitcoin miners have set up in places like Iceland where geothermal energy is cheap and cooling Arctic air is free. Chinese bitcoin miners are known to use hydroelectric power in Tibet to reduce electricity costs. Various potential attacks on the bitcoin network and its use as a payment system, real or theoretical, have been considered. The bitcoin protocol includes several features that protect it against some of those attacks, such as unauthorized spending, double spending, forging bitcoins, and tampering with the blockchain. Other attacks, such as theft of private keys, require due care by users.
Basic Attention Token (BAT) is an open-source, decentralized ad exchange platform built on Ethereum platform. Basic Attention Token held an initial coin offering on May 31, 2017 for its eponymous ERC-20 utility token, raising approximately $35M USD at the time in less than 30 seconds. The Basic Attention Token aims to fix digital advertising, which is broken, fraudulent and opaque. Basic Attention Token work by having advertisers pay BAT to website publishers for the attention of users. The BAT token is designed to correctly value and price user attention within the platform. The Basic Attention Token comprises various components, including attention measurement systems, analytics dashboards and machine learning algorithms. Integration of BAT into a given host application involves implementing BAT Ads, a system that matches and displays ads to users based on locally stored data. Ad targeting is performed wholly on-device, removing the need for third-party tracking. BAT is focused on the Brave browser. Brave is an open-source, privacy-centered browser designed to block trackers and malware. It utilizes blockchain technology to anonymously and securely track user attention, which translates into rewards for publishers. A user's attention, meaning his or her focused mental engagement on digital content like advertisements, is logged through Brave. The makers of BAT indicate that the user's private data and tracking information is stored only on the user's device, ensuring that it is anonymous and private. Created back in 2016, the Basic Attention Token has one of the biggest names behind it, that of Brendan Eich, the creator of JavaScript and the legendary co-founder of Mozilla. Other noteworthy team members include Brian Bondy, lead developer and co-founder of Brave and Scott Locklin, senior engineer, and co-founder of Kerf Software.' Basic Attention Token is created by the team that built the Brave browser, an open-source, privacy-focused browser that blocks ads and trackers. The browser measures user attention and rewards publishers for users attention. Use the Brave browser to protect your privacy and support CoinGecko at the same time: https://brave.com/coi600