The article focuses on the study of blockchain technology at the data layer, namely, the mechanisms for secure exchange of transactions are analyzed. The distributed structure of the blockchain network, built on the basis of a sequence of blocks containing transaction data, is considered. The fundamental features of the blockchain technology are described, as well as the 6-component multilayer blockchain architecture. The importance of using cryptographic hash functions to ensure the security and integrity of data in a blockchain network is shown.
In order to simulate the process of exchanging transactions between network users, an experimental blockchain application was created. This made it possible to clearly demonstrate the features of using such crypto-tools as public and private keys and digital signature to solve the problem of unauthorized transactions. The performance of the experimental blockchain network is analyzed at different values of block mining complexity.
Keywords: blockchain, block, data level, data protection, hash function, transaction, public key, private key, digital signature.