Although it originated more than 10 years ago, the word blockchain has been around lately can hear almost daily. The reason for this is its revolutionary properties and applications, leading the internet into a new era. We are witnessing the emergence of decentralized an application whose foundation is precisely blockchain. Decentralized applications are still at an early stage, but there is a growing need to store data on the blockchain. In this diploma thesis, the functioning of the blockchain and its origin are explained blocks. The save and read solution was successfully demonstrated on a practical example data to and from the Ethereum blockchain through a multiplayer game. There are currently a few ideas that would improve the storage of data in the blockchain, but each idea has its own advantages and disadvantages and it is up to the user to decide which platform suits him best. With all the positive examples of blockchain, there is also a big downside, and that is a big one energy consumption for mining, ie data storage. How to blockchain constantly As it progresses, this problem is intended to be solved in the near future, by switching from “proof of work "way of mining", in the "proof of stake" way, where fewer people will participate in mining, which will have a positive impact on the environment.