Welcome back to my profile, guys!

This time I will be attempting one of the Beginner Level Introductory Courses introduced by Steem it Crypto Academy for anyonw who wants to start learning about Crypto.

These courses are the first step in the ladder, and here is my attempt at it.

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Bitcoin, Cryptocurrencies, Public chains

Question: What Is Public Chain and What will be the Advantages and Disadvantages of Public Chain?

Bitcoin was the first Cryptocurrency to ever invented and when it first came into being, the inventors wanted to make it secure and free of any privacy issues. That's when Block Chain came into play.

Types of Block Chains

• Public Block Chains
  Public Block Chains, as the name implies, are visible and accessible to everyone. Even though transactions are anonymous, which means you do not really know who sent money to which address, but since the transactions are all online and public, Anyone can see it.

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An example of a public blockchain is the one used for Bitcoin, Etherium.

• Private Block Chains
  Now again, the private blockchains are not visible or accessible to anyone other than the main party. This blockchain is mainly for companies that do not want to share their data with anyone. Like in a public blockchain where anyone can contribute to the blockchain, private blockchains do not allow contribution by random people, and the number of nodes in a private blockchain is controlled.

• Federated Block Chains
  Last but not the least, we have Federated blockchains where a group of people or a group of different companies come together to form their own separate blockchain. Just like in a private blockchain, every entity is known in a federated blockchain as well.

Advantages of Public BlockChain

• Open to Everyone
  As discussed earlier, this is the only network where anyone and everyone can join the network. Unlike other blockchain networks, it is not controlled by a single authority. the fact that anyone can join, makes public blockchain the most widely used kind of blockchain among all of the others.

• Highly Secure
  One of the main advantages of a Public Blockchain is that a high level of security is built into the entire blockchain system.
  To brief it a little, different levels of protocols have been designed to create a security mechanism that will increase the level of security in the blockchain. Some of these protocols that have been created are Gossip Protocols which include AES - Advanced Encryption Standard.
  These protocols and security systems have only been improved since they came into being.

• Completely Decentralized
  In a Public BlockChain, the system is completely decentralized, which means there is no main central authority that controls the blockchain, unlike the conventional Banking System.

In other words, we can say the mining community is mainly responsible to validate and confirm all of the transactions in the network.

• Once deployed, it's Free
  Another one of the advantages for public blockchains like bitcoin or ethereum, that once you deploy their applications they are completely free to run in terms of storage, computing powers, resources, RAM, memory, and computational resources.
  You do not have to spend any money at all, even at the end of the year.

Drawbacks of Public Block Chains*

• Comparatively slower
  One of the biggest disadvantages of a public blockchain is that is relatively slower than private or federated blockchains, and I'll tell you why. Since bitcoin and ethereum and other public blockchains use POW - Proof of Work, which takes at least 10 minutes for each block.

We can go into detail but comparing Visa transactions and Bitcoin transactions. The Visa transaction can do up
to 1000 transactions per second and Bitcoin can only do 7-8 transactions per second.

• Wastage of Resources
  By now, we know most public chains, like that of Bitcoin and ethereum uses Proof of Work, we can also agree on the fact that it consumes a lot of energy because there isn't only one node, but also thousands and hundreds of miners who are doing 10 minutes of work only to do 1 transaction which can consume huge amounts of resources.

• Privacy
  As public blockchains are visible to everyone, they can sometimes jeopardize the privacy of the people. Even though as I mentioned earlier the transactions are anonymous but it can be dangerous in some cases. Like when you have company data, which is confidential it will be available on the public blockchain.

• Vulnerable to 51% Attack
  So, everyone says the blockchain is immutable and no one can change it.
  Let us get into detail, for example, we have ten miners, and these ten miners are responsible to control the entire network and the state of fate. So if we have one malicious node, the other nine can easily push it out because they have the power to do so. However, if you have six malicious nodes, that is where the problem starts. Those six nodes can attack the entire blockchain because 51% majority now control the state of fate.

Conclusion

The article not only provides understanding about the public blockchains, but what Cryptocurrency is and hoe Bitcoin came into being.

The purpose of Bitcoin and why, in the advanced, fast age Bitcoin has become the need of hour. Why bitcoin was needed in the first place and what were the objectives behind the invention of Bitcoin and entire blockchain system.

Credits:
@stream4u

By
@kinzaghauri
Achievement 4