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.
ASCH is a new generation block chain innovation application development platform based on side chain structure which is efficient, flexible, safe, low-cost and reused. With the use of JavaScript as its application programming language, the platform makes use of relational databases to store data, drawing similarities between developing a DAPP and developing a traditional web application. This type of platform carries a great deal of appeal to developers, as well as small and medium enterprises, since its ease of use results in greater productivity, fuelling and facilitating a more prosperous ecosystem in the process. ASCH is open in design and is not limited to any particular niche market such as news aggregation, the issue of assets, arbitration, the existence of certificate, property rights certification, the Internet of things, supply chain finance, asset digitization, commodity tracing, prepaid card system, block chain contract deposit etc. In terms of the consensus mechanism, ASCH has inherited and enhanced the DPOS algorithm, simultaneously reducing the probability of forking and double spending by a significant degree. Furthermore, ASCH’S side chain, i.e. the application mode, not only improves scalability by delaying the expansion of the block chain, but also makes DAPPS more flexible and personalized. ASCH is a forward-looking, low-cost and one-stop application solution, which is believed to be a new generation of incubator for decentralized applications. Adhering to the values of enterprise accomplishments, innovation leading, technology belief and embracing future, ASCH is devoted to building a global commercial block chain application ecosystem, which is not only using block chain technology to empower various industries, but also being the base of the world class economy. The services provided by the ASCH platform include a public chain and a set of application SDKs; the public chain is called the main chain. The ASCH application SDKs can be used to develop blockchain applications with a free-running, immutable ledger. These applications are also known as side chain applications. An application SDK has a built-in cross-chain protocol, through which the side chain can communicate with the main chain. In other words, the main chain has the function of asset routing, through which a variety of assets can flow among different applications. ASCH’s ecological system contains multiple chains, with each chain possessing the ability to carry multiple tokens or assets. Each token or asset can also be transferred to multiple chains.