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.
Blocknet (sometimes referred to as Block) is a decentralized, platform-as-a-service protocol that connects the nodes of different blockchains. As you probably know, there are hundreds, if not thousands, of blockchains that currently exist, and this number is showing no signs of slowing down its growth anytime soon. Many of these chains, though, are unable to communicate and interact with each other, creating small groups of siloed ecosystems. And, the inability of these groups to work together is holding back the entire blockchain industry. To solve this problem, Blocknet is working to make blockchains interoperable, mobile, and modular. This enables different chains to provide microservices to each other in a peer-to-peer fashion at higher security, faster speeds, and more efficient scalability than today’s current options. Blocknet is aiming to be the “Internet of Blockchains” through inter-blockchain connective services. Simply put, Blocknet enables you to develop on one blockchain, Ethereum for example, but access the functionality of other chains, like NEO. The team is building the infrastructure using three core components that work together to provide three primary services for these inter-chain decentralized applications (dapps). The XBridge, a blockchain router, is the backbone of the Blocknet platform. It’s the first peer-to-peer protocol to connect nodes on different blockchains, allowing them to communicate with one another. Using the XBridge, you’ll not only be able to perform cross-chain atomic swaps, but you’ll also be able to transfer additional data and execute smart contracts across chains. Blocknet uses a Proof-of-Stake consensus algorithm with three types of nodes to maintain the network. Service nodes collect and distribute trade fees on the platform as well as prevent spamming and DDoS attacks. To run a service node, you need to hold at least 5,000 BLOCK and keep your node computer running at all times. The Blocknet team recommends that, if you plan to run a service node, you should also run multiple full node wallets of whichever coins you want to support. This maximizes the trading fees you receive. Staking nodes confirm network transactions. When running a staking node, you’ll receive 9-14% annual returns from block rewards as well as a portion of the trading fees. There’s no minimum BLOCK amount you need to keep in your wallet to receive these, but you need to keep the wallet running at all times. There’s limited information available on the Blocknet team. Dan Metcalf and Arlyn Culwick founded Blocknet in 2014 as a fork of PIVX. According to his LinkedIn page, Metcalf was a Bitcoin developer for 5 years as well as a Senior DevOps Engineer at Philips. Outside of Blocknet, Culwick is also the PR and Media Liaison for XCurrency. Blocknet launched the service nodes on their main net in September 2017, and on March 1st, 2018, the team will release the beta version of the DEX. The project has also partnered with the 0x protocol to add ERC20 token support on the platform. Blocknet is connecting the isolated blockchain systems that currently exist to create one, cohesive ecosystem. Through the platform’s XBridge, the team is building a blockchain Internet in which you can build dapps that utilize features from several different chains. Starting with a DEX, the project has a lot on its roadmap including a service delivery system for blockchains to provide and receive payment for providing functionality to other chains. This is a complex project, but Blocknet already has the partnerships in place (0x, Poloniex) to see it through to the end. Blocknet consists of the following coins: XCurrency, Stealth, SonicScrewdriver, Fibre, Librexcoin, APEXcoin, BitSwift, XCash, UtilityCoin