CONSENSUS PROBLEM IN PEER-TO-PEER NETWORKS. IMPLEMENTATION OF BANKS’ TRANSACTIONS BASED ON BLOCKCHAIN TECHNOLOGY

Анотація

One of the main problems of modern distributed databases is described - the problem of data integrity, because of none of the nodes is the main one and nobody trust each other in the network. Such systems are called peer-to-peer, wherefunctions of the server can be performed by any client (node).
We tried to describe in details all the basic concepts of blockchain technology, core role of transactions and blocks in the network, told about the unit of trust and where this “trust” is taken. Considered both through the use of digital signatures, asymmetric data encryption and lack of trust, the extraordinary stability and integrity of data in the network is achieved. Check the example of the construction of the Merkle Tree for transactions, computed the minimum number of operations required to find the hash SHA-256 in the case of relatively small complexity of the algorithm.
In practice, it was shown how the easiest blockchain software application works, what roles are in it, and what stages the system runs in its lifecycle. Several types of attacks on blockchain are considered, which protocols are vulnerable and in which conditions they should be used.
An own experiment was conducted to find the hash of the block in case of use of the “proof-of-work” protocol. The average performance rate with a light complexity of the output hash, spent 5 days in a continuous search and analyzed results.
Taking into account all the latest approaches to modeling, constructing, supporting web projects in conjunction with the recommendations for creating blockchain applications, it was proposed to implement its own system of electronic bank with a mixed three-level architecture basede