Silvio Micali: Cryptocurrency, Blockchain, Algorand, Bitcoin & Ethereum | Lex Fridman Podcast #168 | Summary and Q&A

March 14, 2021
Lex Fridman Podcast
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Silvio Micali: Cryptocurrency, Blockchain, Algorand, Bitcoin & Ethereum | Lex Fridman Podcast #168


Blockchain is a distributed ledger technology that enables secure and transparent transactions, while cryptocurrency is a form of digital money that operates on a blockchain. Both have the potential to revolutionize various industries.

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Key Insights

  • ❓ Blockchain technology enables transparent and immutable transactions, which can greatly impact industries beyond finance.
  • 🤑 Cryptocurrency offers a new form of digital money that operates on a blockchain, providing secure and efficient transactions.
  • 🔐 Scalability, security, and decentralization are key challenges in blockchain technology, but efforts are being made to overcome them.
  • ⚾ Algorand is a company that aims to provide a solution to the blockchain trilemma by using a decentralized system based on randomness for consensus.


the following is a conversation with sylvia mccauley a computer scientist at mit winner of the touring award and one of the leading minds in the fields of cryptography information security game theory and most recently cryptocurrency and the theoretical foundations of a fully decentralized secure and scalable blockchain and algorand a company of cr... Read More

Questions & Answers

Q: How does a blockchain ensure transparency and immutability in transactions?

A blockchain allows everyone to write entries in a common ledger, ensuring that all participants have the same copy of the ledger. This transparency prevents tampering or alteration of transactions, providing an immutable record.

Q: What is the significance of cryptocurrency in the context of blockchain?

Cryptocurrency is a form of digital money that exists on a blockchain. It utilizes the transparency and security of the blockchain to ensure that transactions are verifiable and valid. It eliminates the need for intermediaries and enables peer-to-peer transactions.

Q: How does Algorand aim to solve the blockchain trilemma?

Algorand utilizes a decentralized system that relies on randomness for consensus. By randomly selecting participants to validate transactions, Algorand ensures scalability, security, and decentralization. This approach allows for fast and secure transactions without sacrificing decentralization.

Q: Can blockchain technology be applied to other areas besides finance?

Yes, blockchain technology has the potential to revolutionize various industries beyond finance. It can be used for supply chain management, voting systems, legal agreements, and more. Its transparency, security, and immutability make it a versatile solution for various applications.


In this conversation, Silvio Micali, a computer scientist and founder of Algorand, discusses the concept of blockchain, cryptocurrency, and the challenges they face in terms of scalability, security, and decentralization. He explains the importance of a common knowledge ledger and how blockchain ensures transparency and immutability. Silvio compares different blockchain approaches such as proof of work, delegated proof of stake, and Algorand's approach. He highlights the need for scalability in blockchain systems and how Algorand achieves it through a decentralized and secure random selection process. Silvio also shares his thoughts on the future of decentralization and the potential implications of blockchain technology.

Questions & Answers

Q: What is a blockchain and why is it interesting, fascinating, and powerful?

A blockchain is a distributed database or ledger where anyone can write an entry and everyone can read it. It ensures that everyone has the same copy of the ledger, providing a common knowledge base. This common knowledge feature is powerful as it enables transparency and immutability, making it a first for humanity in terms of communication. Unlike other forms of communication, a blockchain guarantees that transactions or information seen by one person can be seen by everyone else, creating a decentralized and resistant-to-centralization system.

Q: What is cryptocurrency in the context of a blockchain?

Cryptocurrency refers to a currency that exists on a blockchain. It is similar to a ledger where different participants can write and read entries, ensuring transparency and trust in the system. Cryptocurrency allows for secure and transparent transactions as the ownership and value of the currency can be directly verified on the blockchain. It removes the need for intermediaries or trusted third parties, making transactions more efficient and reliable.

Q: What is money and why do we have it?

Money is a social construct that simplifies the process of transacting between individuals who want different things. It allows for the exchange of goods and services by creating a shared belief in the value of a particular form of currency. Money enables individuals to receive payment for their work and then use that payment to acquire goods or services from others. It provides a medium of exchange that is widely accepted and trusted within a society.

Q: Does it bother you when money is not directly tied to physical goods like gold?

No, it doesn't bother me because money has always been a social construct rather than directly tied to physical goods. While gold and other physical commodities have historically been used as a medium of exchange, they also rely on social beliefs in their value. The value of money is subjective and based on shared beliefs and societal trust. As long as people share these beliefs and continue to accept a particular form of currency, it can serve as an effective medium of exchange.

Q: What are the goals of a blockchain in terms of scalability, security, and decentralization?

The goals of a blockchain are to provide scalability, security, and decentralization. Scalability refers to the ability of the blockchain to handle a large number of transactions quickly and efficiently. Security ensures that the blockchain is resistant to tampering or malicious attacks. Decentralization ensures that power and decision-making are distributed among many participants rather than controlled by a single authority. Achieving all three goals simultaneously, known as the blockchain trilemma, is a challenge.

Q: How do you achieve scalability in a blockchain system like Algorand?

Algorand achieves scalability by implementing a decentralized and secure random selection process. In Algorand, there are 10 billion tokens distributed among all participants of the network. Randomly selected participants, known as winners, have the responsibility to validate and propose the next page in the ledger. This process ensures that no individual or centralized authority has control over the selection of pages. Each participant executes their own individual lottery, and the winners' opinions and winning tickets are propagated across the network.

Q: What is the purpose of security in a blockchain system?

Security in a blockchain system refers to its resistance against dishonesty or manipulation. It ensures that the contents of the ledger cannot be altered or tampered with. In Algorand, the security comes from the random selection of participants and the requirement that a majority of the selected participants must be honest. This makes it very difficult for any malicious individual or group to corrupt the selection process or manipulate the ledger. The transparency and immutability of the blockchain also contribute to its overall security.

Q: What did Bitcoin and Ethereum get right, and where are they lacking?

Bitcoin was successful in introducing the concept of cryptocurrency and demonstrating the importance of a decentralized and secure ledger. It made it hard to tamper with transactions and provided an initial store of value. However, Bitcoin is lacking in terms of scalability, as it can only handle a limited number of transactions and is slow compared to traditional payment systems. Ethereum, on the other hand, introduced the concept of smart contracts and the ability to securely transact without a trusted third party. However, like Bitcoin, Ethereum also faces scalability challenges. Both projects have made significant contributions but need to address scalability issues to meet the demands of a global financial system.

Q: What are non-fungible tokens (NFTs), and why are they interesting?

Non-fungible tokens (NFTs) represent unique items or assets on a blockchain. They allow for the ownership and trading of digital assets such as artwork, music, or collectibles. NFTs have the potential to revolutionize digital ownership and the way artists and content creators are remunerated. They provide a secure and transparent platform for trading and verifying ownership rights. However, the scalability, security, and decentralization of the underlying blockchain technology are still necessary to fully leverage the potential of NFTs.

Q: Can power be effectively decentralized, considering the tendency for power to corrupt?

While power has historically tended to centralize in systems, technological advancements like blockchain provide an opportunity for decentralized power. Decentralized systems are more resilient and adaptable to change compared to centralized systems. In the past, technologies and communication limitations justified centralization, but now, with the advancements in technology, we have the ability to distribute power more effectively. Decentralized systems are stable and durable, and they can facilitate intelligent adaptation to changing circumstances. However, overcoming the resistance to decentralization may require a shift in societal and organizational structures.

Q: What is the philosophy behind decentralizing governance in Algorand?

The philosophy behind decentralizing governance in Algorand is rooted in the belief that systems and technology need to adapt and evolve to remain relevant and durable. The ability to update, modify, and improve the code is essential for long-term success. Governance should not be fixed in stone but should be flexible and responsive to changing needs and circumstances. Decentralizing governance allows for a diverse range of voices and perspectives to contribute to decision-making, making the system more resilient and capable of intelligent adaptation.

Summary & Key Takeaways

  • Blockchain is a common database that allows everyone to write and read entries in a ledger, providing a guarantee of transparency and immutability.

  • Cryptocurrency is a form of currency that exists on a blockchain, offering transparent and secure transactions, as well as the ability to tokenize assets.

  • Scalability, security, and decentralization are key elements in blockchain technology, and efforts are being made to overcome the blockchain trilemma that claims only two of the three can coexist.

  • Algorand is a company that aims to solve the blockchain trilemma by using a decentralized system that relies on randomness for consensus.

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