Why is it called Blockchain?
Blockchain owes its name to how it works and the manner in which it stores data, namely that the information is packaged into blocks, which link to form a chain with other blocks of similar information.
It is this act of linking blocks into a chain that makes the information stored on a blockchain so trustworthy. Once the data is recorded in a block it cannot be altered without having to change every block that came after it, making it impossible to do so without it being seen by the other participants on the network.
Distributed Ledgers have 3 key attributes:
1. Recorded: stored information is time-stamped
2. Transparent: anyone can see the ledger of transactions.
3. Decentralized: the ledger exists on multiple computers, often referred to as nodes.
Normally, each block contains the data it is recording, for example a transaction like 1 Lisk token being sent from Alice to Bob, as well as timestamps of when that information was recorded will be included within the block. It will also include a digital signature linked to the account that made the recording along with a unique identifying link, in the form of a hash (think of it as a digital fingerprint), to the previous block in the chain. It is this link that makes it impossible for any of the information to be altered or for a block to be inserted between two existing blocks. In order to do so all following blocks would need to be edited too. As a result, each block strengthens the previous block and the security of the entire blockchain improves because it means more blocks would need to be changed to tamper with any information.
When combined, all of these create an unquestionable storage of information, one that cannot be disputed or declared to be untrue.