Blockchains are special databases that can manage transaction data without a central approval authority, without the necessity of mutual trust and complete transparency. The largest and most famous public blockchain is the one from Bitcoin – it operates on a network currently consisting of roughly 5,600 servers on the internet and processes 240,000 transactions a day. In the financial world this is not too much. But what’s impressive is the computing power that is needed for the fraud-free running. For Bitcoin alone almost 60,000 times more computing power is employed than the 500 fastest supercomputers in the world have together. The blockchain is therefore a „unwilling“ supercomputer, because the energy input is generated artificially. For every “block” of transactions written in the blockchain other computing tasks need to be solved. This prevents fraud, although no one needs to trust the other. This security principle is called "Proof of Work". The large effort is also one of the reasons why most blockchain initiatives for companies and institutions rely on „private“ blockchains. Only this way can the "Proof of Work" be susbstituted with a less complex method of protection. The "Golem Network", on the other hand, is supposed to turn a need in to a virtue. A decentralized supercomputer is supposed to be developed based on the blockchain principles, with resources that can be booked for intensive computing tasks as necessary.