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.
MATRIX AI Network (MAN) is a global open-source, public, intelligent blockchain-based distributed computing platform and operating system that combines artificial intelligence (AI) and blockchain. MATRIX was created to make blockchains faster, more flexible, more secure, and more intelligent. Besides boasting an impressive 50.000 transactions per second, there are a couple of features which makes Matrix AI Network stand out from its competitors. Matrix adopts a Hybrid PoS + PoW consensus mechanism instead of the traditional Hash computations. The mechanism makes use of value-added computation through the use of the Markov Chain Monte Carlo (MCMC) computations. This computation set is to be used as the Proof-of-Work protocol. This allows the mining process to not only generate MAN tokens but to also be used to power real-world applications. Currently being used in collaboration with Beijing cancer Research hospital to improve speed and accuracy of a cancer diagnosis. While the project seems ambitious with the integration of a working AI in so many areas, the AI-part is already done. Matrix now only has to deliver a working blockchain solution. MATRIX will be launching several community activities after its testnet launch, including a Bug Bounty Program and a Dapp competition, as well as introducing the MATRIX Blockchain Browser and Online Wallet Prototype. Details and instructions will be shared over the coming weeks. Full manner is set to launch December 2018. The MATRIX mining machine is set to launch for sale end of the year 2018.