Blockchain is the technology that makes it possible to store records in a public peer to peer network. This kind of technology allows someone to transfer the ownership of a piece of information to another user, the same time is preventing the replication from a third party. While a transaction begins, the system signs and pack it with other transactions that happened the last 10 minutes in the network, the packet of the transactions is called block.
Every block has a timestamp and transmitted to the network for validation by multiple independent nodes ( the nodes are the miners, which provide computing power for verification in the p2p network and for exchange get transaction fees or coins generated by the network). When the nodes complete the validation, the block is attached to public ledger the blockchain and the change is transmitted to all nodes that contain full copies of the public ledger.
One of the blockchain applications is bitcoin, a digital currency that allows the transfer value from one individual to another, in the bottom line is just a creation of new records in a public distributed ledger. The logic behind the electronic currency is the same as buying products with your credit card, in the backend is a change in banks records, the difference here is that the change of records is stored to bitcoin decentralized network instead of keeping them in a central authority.
Decentralized applications DApps
Another application is smart contracts that can run in network ethereum a p2p network. Instead of deploying only a currency, you can use smart contracts which are objects that contain functions of codes. So the creator of a contract can define initially the behavior of the contract when deploying the contract the execution or the duration of it is provided by the ethereum network. Ethereum makes broader use of blockchain technology to run decentralized applications in their p2p network. Examples of smart contracts are an auction, a crowdfunding campaign without a third party involved, a voting mechanism.
Anyone can write and deploy contracts on various platforms like Ethereum, Neo and others. In case of ethereum this is possible learning solidity