Blockchain technology was originally developed for the cryptographic currency Bitcoin. The functional principle of blockchain is based on assigning a timestamp to information in the form of blocks and adding them to the existing blockchain. This continuous chain of information on all past transactions is shared publicly and is thus tamper-proof (Yli-Huumo et al. 2016)
4.1 Smart Contracts
Smart contracts or intelligent contracts are based on blockchain technology and have the potential to revolutionize contracts. The contractual terms are saved in the blockchain and the transactions are automatically executed upon fulfillment of the contract. A single involved party can thus subsequently neither modify the contractual terms nor refuse payment. This enables safe contract conclusions, even if the trustworthiness of the contractual partner cannot be verified (Banasik et al. 2016; Luu et al. 2016).
4.2 Information Management
Blockchain technology can be used to record the ownership of digital goods. The underlying principle of decentralized, transparent, and immediate access to the information constitutes the starting point for various markets (Mettler 2016).
In the healthcare sector, blockchain technology can be used to realize a decentralized database which doctors, caregivers, therapists, and insurance providers can access. The data is always up-to-date and all interactions between doctors and patients are documented. Despite all this, privacy is ensured and the data is protected against tampering (Yue et al. 2016a).
One other application is managing the enforcement of ownership rights, for example to musical compositions (Mettler 2016).
4.3 Reputation Systems
The reputation of a user indicates how trustworthy he is on an online platform. Reputation systems are used e.g. in online shops, where buyers and sellers are rated. The reputation is calculated and stored on a central server. This carries the risk that unauthorized parties may gain access to the server and tamper with the ratings, or the operator himself might modify the data in his own interest. A reputation system based on a blockchain is protected against tampering and can also be applied to decentralized systems such as peer-to-peer networks (Dennis and Owen 2015; Schaub et al. 2016).
The creditworthiness of states and companies is assessed by rating agencies. With blockchain technology, the rating can be made more transparent and plausible without revealing confidential company data, the rating methods, or the associated models. This avoids conflicts of interest and collusion between the agencies (Yue et al. 2016b).
4.5 Bitcoin Mining
Bitcoin mining refers to the generation of Bitcoins whereby users provide their computing power for the verification of new transactions. The cluster contains articles which investigate more efficient mining methods and those which research behavior patterns and dynamics on this artificial market (Chavez and Kleber da Silva Rodrigues 2016; Cocco and Marchesi 2016; Göbel et al. 2016).