The data is bundled into data blocks that include a hash of the previous data

block’s data; within the newest data block is the hash chain, an append-only

data structure. Any modification to a data block will change the hash digest

recorded by the following data block providing evidence of tampering with

this data structure.

Hash digest

It is the output of a hash function. For example, hash(data) = digest.

Hash rate

Denominated as hashes per second, hash rate is the number of

cryptographic hash functions a processor can usually calculate in a given

time.

Hashing

By applying a cryptographic hash function to the input data, it is a method

of calculating a relatively unique output (called a hash digest) for the input

of nearly any size (a file, text, image, and so on).

Immutable

Immutable refers to the data that can only be written, not modified, or

deleted.

Ledger

A ledger is a record of transactions.

Lightweight node

It is a blockchain node that does not need to store a full copy of the

blockchain and often passes its data to full nodes to be processed.

Mining

Within a proof of work consensus model, it is the act of solving a puzzle.

Pending transaction pool

The candidate transactions wait in the pending transaction pool until they

are added to the blockchain. It is the distributed queue, also known as

memory pool or mempool.