1. Two types of Blockchain
   1. Permission less Blockchain
      1. Example: BTC,ETH
      2. They cannot run without crypto currencies.
   2. Permission Blockchain
      1. Example: Centralized
      2. They can run without crypto currencies.
2. Quantum computers are expensive to make and maintain as well.
3. Bitcoin halving reduces the reward the miner gets after verifying the bitcoin transaction.
   1. It happens after every 4 years
4. The miner gets a gas fee and BTC combined as a reward to verify the BTC transaction and add a new block to the bitcoin blockchain.
5. DAO stands for Decentralized Autonomous Organization
   1. It is open source
6. The first block of the blockchain is the Genesis Block.
7. NFT stands for Non-Fungible Tokens.
   1. ERC-20 helps us launch new fungible tokens.
   2. ERC-721 supports only NFT.
      1. It allows only one operation at a time
      2. It allows only one NFT to be launched at a time.
   3. ERC-1155 supports both NFT and fungible tokens as well.
      1. It is an upgraded version of the ERC-721.
      2. It allows multiple NFTs to be launched together.
      3. It allows multiple operations at a time.
8. EIP stands for Ethereum Improvement Proposal.
   1. EIP 1559
   2. It introduced a base fee for the transaction and developed a feature called Miner Tip.
      1. Base fee will be burned in this.
      2. It will differ according to the transaction and traffic on the blockchain.
   3. The block size increased from12.5 million to 25 million.
9. Lightning Network is made up on Bitcoin Blockchain to solve the problem of scalability.
   1. It is on Layer 2.
   2. It is extremely fast.
10. The Cryptographic hash function doesn’t has inverse function.
    1. It means we cannot find input from the output given when input is considered in the function.
    2. Output is unique for every value.