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description: A super brief summary of the chapter
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# TL;DR 👀

<mark style="color:purple;">**Why is Blockchain So Popular?**</mark>

<mark style="color:purple;">Benefits of blockchain technology: Highly secure, Decentralized system, Automation capability</mark>

<mark style="color:purple;">Blockchain disruption in five key industries: Banking, Cyber security, Supply chain management, Healthcare, Government</mark>



<mark style="color:purple;">**Introduction to Blockchain**</mark>

<mark style="color:purple;">Brief history of blockchain</mark>

<mark style="color:purple;">The key components of blockchain technology: Distributed ledger technology, Smart contracts, Public key cryptography</mark>

<mark style="color:purple;">How blockchain works</mark>



<mark style="color:purple;">**Blockchain vs Bitcoin, Database, Cloud**</mark>

<mark style="color:purple;">The differences between Bitcoin and blockchain</mark>

<mark style="color:purple;">The difference between a database and a blockchain</mark>

<mark style="color:purple;">The difference between blockchain and the cloud</mark>



<mark style="color:purple;">**Consensus Mechanism**</mark>

<mark style="color:purple;">Consensus mechanisms maintain trust and security in a blockchain</mark>

<mark style="color:purple;">Proof of Work relies on code, Proof of Stake relies on validators</mark>



<mark style="color:purple;">**Public and Private Keys**</mark>

<mark style="color:purple;">Private keys are only visible to the owner</mark>

<mark style="color:purple;">Public keys are visible to everyone</mark>

<mark style="color:purple;">Private keys give control over assets, public keys prove ownership and are used in transactions</mark>



<mark style="color:purple;">**Hash functions and Cryptography**</mark>

<mark style="color:purple;">Ensure integrity</mark>

<mark style="color:purple;">Secure against unauthorized modifications</mark>

<mark style="color:purple;">Enable you to verify and securely store passwords</mark>

<mark style="color:purple;">Operate at different speeds, suiting different purposes</mark>



<mark style="color:purple;">**Sharding**</mark>

<mark style="color:purple;">Helps to scale blockchains</mark>

<mark style="color:purple;">Achieves scaling through blockchain nodes, hortizontal partitioning, and shard sharing</mark>



<mark style="color:purple;">**Types of Blockchains: PoW, PoS and Private**</mark>

<mark style="color:purple;">Public blockchain networks are free to anyone</mark>

<mark style="color:purple;">Private blockchain networks grant interaction to certain entities</mark>

<mark style="color:purple;">Permissioned blockchain networks requires an invitation to join</mark>



<mark style="color:purple;">**Understanding Cryptocurrency**</mark>

<mark style="color:purple;">A cryptocurrency is a digital or virtual currency that is secured by cryptography</mark>

<mark style="color:purple;">Cryptocurrencies have many advantages as well as disadvantages</mark>



<mark style="color:purple;">**Coins vs Tokens**</mark>

<mark style="color:purple;">Coins are base layer blockchain currencies</mark>

<mark style="color:purple;">Tokens are built on blockchains with smart contract functionality</mark>



<mark style="color:purple;">**Blockchain Trilemma**</mark>

<mark style="color:purple;">Blockchains face a tradeoff between being decentralized, scalable and secure</mark>



<mark style="color:purple;">**Legality**</mark>

<mark style="color:purple;">Crypto legality varies based on national jurisdiction</mark>

<mark style="color:purple;">Some cryptocurrencies are considered securities while other are not</mark>





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<summary><mark style="color:yellow;">References</mark></summary>

[<mark style="color:yellow;">https://www.simplilearn.com/tutorials/blockchain-tutorial/why-is-blockchain-important</mark>](https://www.simplilearn.com/tutorials/blockchain-tutorial/why-is-blockchain-important)

[<mark style="color:yellow;">https://www.investopedia.com/terms/b/blockchain.asp</mark>](https://www.investopedia.com/terms/b/blockchain.asp)

[<mark style="color:yellow;">https://www.ibm.com/sg-en/topics/benefits-of-blockchain</mark>](https://www.ibm.com/sg-en/topics/benefits-of-blockchain)

[<mark style="color:yellow;">https://www.getsmarter.com/blog/career-advice/the-truth-about-blockchain-myths/</mark>](https://www.getsmarter.com/blog/career-advice/the-truth-about-blockchain-myths/)

[<mark style="color:yellow;">https://www.investopedia.com/terms/c/consensus-mechanism-cryptocurrency.asp</mark>](https://www.investopedia.com/terms/c/consensus-mechanism-cryptocurrency.asp)

[<mark style="color:yellow;">https://www.tutorialspoint.com/difference-between-private-key-and-public-key</mark>](https://www.tutorialspoint.com/difference-between-private-key-and-public-key)

[<mark style="color:yellow;">https://www.thesslstore.com/blog/what-is-a-hash-function-in-cryptography-a-beginners-guide/</mark>](https://www.thesslstore.com/blog/what-is-a-hash-function-in-cryptography-a-beginners-guide/)

[<mark style="color:yellow;">https://www.investopedia.com/terms/s/sharding.asp</mark>](https://www.investopedia.com/terms/s/sharding.asp)

[<mark style="color:yellow;">https://near.org/blog/near-launches-nightshade-sharding-paving-the-way-for-mass-adoption/</mark>](https://near.org/blog/near-launches-nightshade-sharding-paving-the-way-for-mass-adoption/)

[<mark style="color:yellow;">https://www.ibm.com/my-en/topics/what-is-blockchain</mark>](https://www.ibm.com/my-en/topics/what-is-blockchain)

[<mark style="color:yellow;">https://www.investopedia.com/terms/c/cryptocurrency.asp</mark>](https://www.investopedia.com/terms/c/cryptocurrency.asp)

[<mark style="color:yellow;">https://blog.liquid.com/coin-vs-token</mark>](https://blog.liquid.com/coin-vs-token)

[<mark style="color:yellow;">https://medium.com/certik/the-blockchain-trilemma-decentralized-scalable-and-secure-e9d8c41a87b3</mark>](https://medium.com/certik/the-blockchain-trilemma-decentralized-scalable-and-secure-e9d8c41a87b3)

[<mark style="color:yellow;">https://www.investopedia.com/terms/c/cryptocurrency.asp</mark>](https://www.investopedia.com/terms/c/cryptocurrency.asp)



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