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joplin notion extension/Web Development/Blockchain/Theory 2.md

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+Theory 2
+
+## Etherium
+Developed by Vitalik Buterin. Eherium used to use POW but now from sep 2022 it uses POS.
+**Why Etherium?**
+Unlike bitcoin which is decentralized cash app(cryptocurrency), etherium if for decentralized apps(dApps). It has concept like EVM(Etherium Virtual Machine). To run softwares in etherium network, EVM is needed. Here Ether is cryptocurrency in etherium network
+### Smart Contract
+If there is a company say B from which user  A wanna order product. That company may or may not be trusted. Also comapnay B will give commision to delivery service C. But what if delivery C is not trustable and dont deliver product at all. 
+So using **smart contract** means automating the payment so the money will get transferred automatically once the product is delievered to B from A and to C from B
+![5ce456f2f04a3c7694fe75c00c935acb.png](../../../_resources/5ce456f2f04a3c7694fe75c00c935acb.png)
+Benefits
+- Fast
+- Secure bcz of blockchain
+- Trust
+ 
+
+### Drawbacks of Blockchain
+1. Complex : So many terms like consensus,chain, nodes and miners and complex technology, providing coordination.
+2. Slow : Bitcoin transaction speed is about 7-10 transactions/sec wheras visa is 1000 transactions/sec.
+3. Bitcoin and etherium is using proof of work which waste so much resources/energy.
+4. In case of public blockchain it is true that name will be anonymous but how much transaction has taken place will not be anonymous and known to everyone
+5. 51% attack : if more than 50% of miners r malacious then they can attack the whole blockchain.
+6. Here is an example about transactions being public
+https://www.blockchain.com/explorer/addresses/btc/3M6XXpqUc8G8GuHYKQhjAWobo5aGpkdV7u
+7. Law enforcement requests information from Coinbase all the time. See https://www.coinbase.com/blog/transparency-report-2023
+
+### Hyperledger
+Hyperledger is an open source project having different frameworks and tools to build blockchain. It is hosted in the linux foundation. As public blockchain has its drawbacks so companies and transactions especially B2B instead of B2C want their own blockchain so they start making open source tools for that.
+Frameworks
+- Iroha
+- Sawtooth
+- Fabric
+- Indy
+- Burrow
+
+Tools
+- Hyperledger Composer
+- Hyperledger Cello
+- Hyperledger Quilt
+- Hyperledger Explorer