What is blockchain?
A blockchain essentially records data. It’s a digital ledger of sorts, capturing transactions and details, assets or agreements. Just about anything! In a distributed ledger system, all these information needs to be recorded and verified. It is distributed across multiple computers, usually in a public doman, hence the name.
Blockchain is a unique type of dataset where the data in stored in blocks (chain of blocks, see!), and built up in successive blocks. Each of the blocks of data includes some data that verifies the content of the previous block (the hash solution). Because each link in the chain verifies the previous link (the hash solution is unique), the system is able to detect and reject any attempted unauthorised modification, making the ledger tamper-proof (well, almost). To make changes to the existing data will require huge computational power, that just 1 person will not be able to accomplish.
Each participant in the system is uniquely identified, while everyone is able to add data to the chain, only authorised persons (miners) can make changes to the blockchain.