Structure of blockchain

Workflow

Dictionary

• Node - user or computer within the blockchain architecture (each has an independent copy of the whole blockchain ledger)
• Transaction - smallest building block of a blockchain system (records, information, etc.) that serves as the purpose of blockchain
• Block - a data structure used for keeping a set of transactions which is distributed to all nodes in the network
• Chain - a sequence of blocks in a specific order
• Miners - specific nodes which perform the block verification process before adding anything to the blockchain structure
• Consensus (consensus protocol) - a set of rules and arrangements to carry out blockchain operations

Architecture

Centralized

Each node of the internet send the content for a unique server(datacenter) and only this server could process and interpret the information

Decentralized

A new way of implement applications and handle data, each node of the network could process and interpret the information

Distributed Ledgers

• Public
  A public ledger is how bitcoin is currently working, anyone could connect, process and use

• Private
  Private ledgers are only for persons that the administrator of the network allows you to enter, a example is a bank private ledger

Web 2 X Web 3

• The traditional architecture of the World Wide Web uses a client-server network. In this case, the server keeps all the required information in one place so that it is easy to update, due to the server being a centralized database controlled by a number of administrators with permissions.
• In the case of the distributed network of blockchain architecture, each participant within the network maintains, approves, and updates new entries. The system is controlled not only by separate individuals, but by everyone within the blockchain network. Each member ensures that all records and procedures are in order, which results in data validity and security. Thus, parties that do not necessarily trust each other are able to reach a common consensus.

Technology

The structure of blockchain technology is represented by a list of blocks with transactions in a particular order. These lists can be stored as a flat file (txt. format) or in the form of a simple database. Two vital data structures used in blockchain include:

• Pointers - variables that keep information about the location of another variable. Specifically, this is pointing to the position of another variable.
• Linked lists - a sequence of blocks where each block has specific data and links to the following block with the help of a pointer

Types of Blockchain

All blockchain structures fall into three categories:

• Public blockchain architecture

A public blockchain architecture means that the data and access to the system is available to anyone who is willing to participate (e.g. Bitcoin, Ethereum, and Litecoin blockchain systems are public).

• Private blockchain architecture

As opposed to public blockchain architecture, the private system is controlled only by users from a specific organization or authorized users who have an invitation for participation.

• Consortium blockchain architecture

This blockchain structure can consist of a few organizations. In a consortium, procedures are set up and controlled by the preliminary assigned users.

The following table provides a detailed comparison among these three blockchain systems:

Property	Public blockchain	Consortium blockchain	Private blockchain
Consensus determination	All miners	Selected set of nodes	Within one organization
Read permission	Public	Public or restricted	Public or restricted
Immutability level	Almost impossible to tamper	Could be tampered	Could be tampered
Efficiency (use of resources)	Low	High	High
Centralization	No	Partial	Yes
Consensus process	Permissionless	Needs permission	Needs permission

Key Points

• Nodes within P2P network
• Properties of block & genesis block
• Transactions within the ledger
• The validation process - mining
• The “consensus” within a blockchain architecture
• Proof-of-work