Blocks

Blocks are nothing but a group of transactions that's always added to the end of chain. It's called a chain because a block always contains the information of the previous block and this forms the chain.

chain is chronological

The chain is sorted in chronological order and this is ensured by always adding the new block only at the end of the chain.

Main USP

The main USP of block chain technology is the trustless and no single authority.

peer to peer

Peer-to-Peer in a block chain has two meanings

• Direct transactions between two parties.
• underlying bitcoin network also works peer-to-peer. No central controlling system.

Validation

The validating nodes must validate and approve the blocks generated. Normally not all validating nodes must approve. The protocol or the framework might say that at least 2/3 rd of the full node must approve.

If any node doesn't approve, the block is discarded and not added to the chain.