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.
nOS is a virtual operating system that introduces a new, decentralized internet. On this new internet user data is safe, and it only goes where the user wants it to go. nOS solves key issues surrounding dApp development, deployment, discovery, and interaction, allowing for true adoption of decentralized applications and blockchain technology. Because applications can choose to make their back-ends fully open-source and transparent, this new implementation of the World Wide Web is defined as the Open Internet. On nOS, applications and websites can be deployed in a completely open and decentralized manner by integrating smart contracts, client-side code, and public-key cryptography. Unlike server-side backend code, smart contracts can be open for all to read, allowing users to review how their data will be transmitted before any final commitments to action. Client-side code and other frontend materials can be distributed via nOS Filesystem, a decentralized file sharing protocol that allows for secure and transparent distribution of static files. By serving both backend logic and frontend material in an open-source, decentralized manner, true transparency between user and application can be achieved. dApps that are deployed to nOS can be accessed through nOS Client, a software solution for desktop and mobile that (among other features) introduces nOS Browser. nOS Browser functions as a web browser, with the added benefit that it integrates with the nOS Protocol, a blockchain-powered web protocol that facilitates secure and open accessibility of nOS dApps. The nOS Protocol resolves domain names that exist on nOS Name Service, a blockchain-powered decentralized implementation of a Domain Name Service, and allows for dApps to register domain names which are discoverable on nOS (e.g. mydapp.neo or my-dapp.eth). The dApp Gateway is a user-friendly dApp discovery platform (or “App Store”) where rankings are decided in a completely decentralized manner via Decentralized Authority. In order to achieve the features such as the ones described above, nOS is powered by the nOS Utility Token. The nOS Utility Token employs various staking and reward utilities which are intended for developers who wish to deploy and maintain dApps on nOS, and for end-users who wish to practice governance by Decentralized Authority. nOS eliminates the need for end-users to manually exchange crypto-currencies in order to make use of various dApps. By integrating crypto-currency exchange APIs, nOS Client automatically converts primary blockchain platform currencies (e.g. NEO/GAS for NEO, ETH for Ethereum) into the required amount of application tokens that are needed to make specific transactions or invocations.