by a reasonable number of nodes before it is registered. On confirmation,

the record is stored in the ledger and is propagated across the network of

participants. The record types are blocks and transactions.

Blockchain formation

The genesis block (in green) forms the longest series of blocks. The current

block is the main chain (in black). The blocks in purple color are orphan

blocks that exist outside of the main chain.

Figure 2.2 depicts the blockchain formation.