Blockchain Technology 區塊鏈技術

Chinese version is here.

What is blockchain technology ?
In various blockchain introduction articles, I think the following article is very appropriate and can be read carefully.
https://www.cbinsights.com/research/what-is-blockchain-technology/

The following terms are mentioned in the text, all of which are easy to understand, for PC: ctrl F / mob: find in the web page to search
· Blockchain
· distributed ledger
· cryptocurrency
· Bitcoin (比特幣) ₿
· mining (挖礦)
· PoW -Proof of Work (consensus mechanism)
↑The diagram above clearly describes bitcoin transaction
· Ethereum (以太坊)
· smart contract (智能合約)
· Proof of stake
· ICO (Initial Coin Offerings)
· NFT (non-fungible tokens)
· Facebook Diem (ex-Libra) (天秤幣)
· metaverse (元宇宙)
https://www.cbinsights.com/research/metaverse-virtual-world-retail/
that is why facebook.com / fb.com are renamed meta.com

In general, the main characteristics of blockchain can be easily remembered by IDD AT&T:
Immutability 防篡改
Decentralization 去中心化
Distributed Ledger 分布式
Anonymous 匿名性
Transparency 開放性
Trustless 去信任

Based on a variety of application participation methods, blockchains are currently mainly divided into public blockchains, alliance blockchains and private blockchains, as shown in the figure below.

In addition to the Ethereum development platform, there is Hyperledger developed by the Linux Foundation;

And Bitcoin only uses blockchain technology, and blockchain application sectors are really numerous.

My programming part:

I also wrote a simple blockchain on my website (ahlo.hk), using pure JavaScript object oriented programming (OOP), refer to this youtube, and change the program to use CDN (Content Delivery Network) instead.

Take a look of the source codes first.↓ Copy link below then paste it on browser's address bar.

add two entries
myCoin.addBlock(new Block(1,"10/10/2020",{ amount: 4 }));
myCoin.addBlock(new Block(2,"11/11/2021",{ amount: 10 }));
Because Javascript console.log is used, remember to open the console (press F12) after [run button] below clicked,
to have output result.
(Limited to PC, mob. cannot run it because of no F12 key)

Output:

If the console.log is converted to HTML output, result is shown below.
(Both PC, mob. are OK)

Example to check integrity being modified

↑source codes

myCoin.chain[1].data = { amount: 100};tamper the first entry
myCoin.chain[1].hash = myCoin.chain[1].calculateHash();recalculate the Hash

Output:
"Is blockchain valid? ===> true" ( originial data)
"Is blockchain valid? ===> false" ( amount is tampered)
"Is blockchain valid? ===> false" ( Hash value recalculated )
This blockchain is proved valid!

Summaries:

0/ Writing blogs is actually to record one's own experience, because it will be quickly forgotten in the future.

1/ Blockchain technology is very similar to BT (BitTorrent) download technology.

2/ Blockchain is equal to the previous PKI (Public & Private Infrastructure) public key + private key + Hash value + digital signature that the previous and existing blocks are connected in series forming the distributed ledger. Undoubtedly such is an improvement.

3/ I just want to know about Bitcoin, I will not participate in trading, because I doubt its consensus mechanism (proof of work), and the mining process consumes too much energy, which is not environmental friendly.

4/ With IoT, 5G/6G communication, VR & AR (Virtual Reality & Augmented reality) and other technologies, the metaverse may be realized the virtual life of Gen Z , like remote surgery, not remote diagnosis. (that is, the doctor does not have to be on-site but uses a remote control robot to perform surgery instead.) The patient pays in cryptocurrency afterwards.

5/ The Metaverse may show that because different races have different languages, or even different dialects, they can also enter the virtual conference room with large number of audience at the same time to hold a general meeting together. Each person can speak instantly in their own words such as "Cantonese", and the other audience immediately hears their own language such as "French", and vice versa.

6/ The virtual world is out of reality, and what is not possible in real life can be realized in the virtual space, but once you enter it, you do not want to return to the cruel real world.

7/ The late Professor Stephen William Hawking, was an atheist. He did not encourage or recommend technologies such as AI, because he was afraid that human beings would be unable to extricate themselves from the virtual world, right or wrong? For those who believe in God, God knows!

Date: 2022 Mar 27