![Task 4.png](https://cdn.steemitimages.com/DQmPQuN98muzVqFJkuxd6xVrawuZMqKxVsZ6AfcGHh5zxiH/Task%204.png) [Source](https://steemit.com/hive-108451/@sapwood/crypto-academy-season-3-beginners-course-task-4-different-types-of-consensus-mechanisms)

(1) What is the difference between PoW & PoS? Advantages & Disadvantages? Which one is better in scaling Capacity? Examples?

![IMG_20210904_152237.jpg](https://cdn.steemitimages.com/DQmbqGYcTbxuF2tWGAEYuNf6MLaFvCHSpvS8ESbQDYvBkuA/IMG_20210904_152237.jpg)

The world's first blockchain, bitcoin, uses the PoW consensus algorithm, then the blockchain acts to innovate by developing several other consensus algorithms. There are many consensus algorithms that can be used, but the most popular are PoW, PoS, DPoS. Now let's discuss the general understanding of how Proof of Work and Proof of Stake work, then we will discuss the difference.

* ### PoW To join a blockchain network that uses the PoW consensus algorithm, then we have to run a node, the node is called a miner, then we also have to have sophisticated computing tools such as CPU, GPU, ASIC, FPGA and high voltage electricity. The way it works is quite complicated, a miner must validate every transaction made on the blockchain to solve very complicated mathematical puzzles, because of this we must have super-sophisticated computing tools.

When a blockchain user makes a transaction, the transaction details such as timestamp, public key, recipient public key, and also the transaction value will be sent to the network. These transaction details will be collected into a single block spread across the network. Then the miner will check all the details of the transactions in the block, and who is the fastest to find a solution to the math puzzle is the winner, and is entitled to a prize and add a new block to the blockchain.

* ### PoS The Proof of Stake consensus algorithm does not require computational tools to run nodes, nodes in the blockchain network that use the PoS consensus algorithm are called validators. The goal is the same as the PoW consensus algorithm, namely by validating transactions and also adding new blocks, but with a different mechanism.

Validators don't have to solve complex math puzzles like in PoW to be the fastest to get rewards, and the right to add new blocks, but they just need to hold as many coins as possible to become validators. The energy consumption of this algorithm is also not too large and the network scalability is more reliable.

The way it works is almost the same as PoW, namely by spreading all transaction details to the network to be validated by validators. But validators don't have to compete with other validators to be the fastest because validators are selected based on the number of coins they hold, nor do they have to solve complex math puzzles.

### The difference between the two

![IMG_20210904_152320.jpg](https://cdn.steemitimages.com/DQmTYZciXjfX59y3emNjcXePLxwux1CpKSEgpQP7eFcdtfb/IMG_20210904_152320.jpg)

### Advantages of Proof of Work

**1. Safe against Ddos attacks** The consensus PoW algorithm provides protection from Ddos attacks, hackers must have at least 51% computing power to attack the network, this is almost certainly not going to happen because the blockchain network and also the hashrate is very high. So it requires high computing capacity and calculations that take a long time and cost a lot of money.

**2. Decentralized** The PoW consensus algorithm also provides full decentralization so that we have full control over the distribution. This is certainly an advantage for coin owners because it is safe from hackers and is free to manage their assets according to the wishes of the coin owner.

**3. Fair** Another advantage, we can't buy rankings even though we have a lot of coins, this doesn't affect the decision makers for the whole network, because the main thing we have to have is super fast computing ability to solve puzzles and produce new blocks.

### Disadvantages of Proof of Work

**1. Expensive computing tools** To become a miner we must have very strong and fast computing power, this of course costs a lot of money to buy it so it is unlikely that everyone can become a miner.

**2. Waste of energy** Using a sophisticated computer coupled with computing tools will certainly require a large amount of energy, this will certainly have a bad impact on the environment because of the excessive use of electricity which may be fatal for the future of our earth.

**3. Lack of network scalability** Blockchain that uses the PoW consensus algorithm as its foundation creates scalability problems on the network, therefore submissions will take a long time to process. The block size of the PoW algorithm blockchain is very small, it is not good for supporting thousands of transactions making it very slow.

### Advantages of Proof of Stake

**1. Energy saving** The main advantage of this algorithm is that it saves energy, this is certainly very good for the environment and also for validators because it will not spend a lot of money to pay for electricity.

**2. Does not require elite computing power** We don't need elite computing power to join as validators on the network, just with minimal computing power we can join and become validators. This makes the PoS algorithm energy efficient because it does not need to use excessive computing power.

**3. Better network scaling** The PoS algorithm has better and stronger support for the network, with better scaling enabling nodes to process transactions quickly.

### Disadvantages of Proof of Stake

**1. Not fully decentralized** The consensus PoS algorithm is not fully decentralized blockchain, it looks bad because people need a fully decentralized blockchain that allows us to freely control and manage it.

**2. Rich people can rule the network** We certainly don't want one entity to manage the network and validate blocks, but what can we do because the PoS consensus algorithm chooses validators based on coin ownership.

**3. Holding a coin is more profitable than releasing it** People who are better off financially may not give up their holdings on the contrary, i.e. keep buying coins and risking them because they will get more profit than releasing them.

**4. The next validator is selected based on coin holdings** This is certainly not good because it will reduce the opportunity for people who are less able to become validators. Although it does not require elite software and super computing power, but we must have a lot of money to buy coins.

![IMG_20210904_152352.jpg](https://cdn.steemitimages.com/DQmTsRkcXtF2zjyENKDzRHDizFVT4oriYEeRPFc43KmDS3z/IMG_20210904_152352.jpg)

As I mentioned in the pros and cons of these two algorithms, PoS is better at scaling and is also energy efficient. The block size of the PoS algorithm is more stable and able to process transactions quickly.

While the PoW algorithm is not very good in terms of scaling because the block size is too small to process thousands of transactions so it takes a little slow.

![IMG_20210905_031000.jpg](https://cdn.steemitimages.com/DQmYMUJSP6FZfGH9arDXE7iqPLAB45N36wCW9fLa62SVK8D/IMG_20210905_031000.jpg) **List of blockchains using PoW algorithm** * Bitcoin (BTC) * Dogecoin (Doge) * Monero (XMR) * Litecoin (LTC)

**List of blockchains using PoS algorithm** * Gridcoin (Grc) * NXT * koin hitam * Cardano (ADA)