Large memory requirements: A blockchain gets longer with each new block. This means that the memory requirements of the nodes in the network – which save the entire blockchain and verify the data blocks that are added – also increase. Limited scalability: One of the biggest challenges of public blockchains is to meet the requirements of rapid user adaptation without neglecting the aspects of decentralisation. In order to solve this scaling problem, sustainable solutions are already being researched. Low data throughput: Payment systems such as those of credit card companies can currently process considerably more transactions than a public blockchain. The data throughput (the net amount of data per time that can be transmitted over a network) of a classic blockchain solution is still limited. However, research is underway to increase the data throughput significantly. In addition, private blockchain solutions already offer possibilities to process larger amounts of data simultaneously. Technically sophisticated: Blockchain is still a very young technology, which is why only a few IT experts currently have the necessary skills to adequately design or further develop a blockchain network. Furthermore, many of the blockchain applications currently in use are not yet fully developed, even from the user-interface point of view. However, the applicability is constantly evolving so that a continuously improving user-friendliness can be expected.