Can a blockchain exist without miners, proof-of-work, or blocks? What are the implications for security, trustlessness, and decentralisation? Not all distributed ledgers are blockchains. What is the influence of alternative energy generation on mining in proof-of-work cryptocurrencies? Should we use alternative algorithms that generate "useful work" in addition to mining cryptocurrencies? The hard promises that Bitcoin provides are valuable and useful in themselves. What is the difference between proof-of-work and proof-of-stake? Note: These sessions were recorded live using Google Hangouts. The audio and video may be slightly out of sync at some points. These questions are from the MOOC sessions 7.2 and 8.2, covering the Byzantine Generals' Problem, which took place on February 26th 2017 and September 15th 2017 respectively. Andreas is a teaching fellow with the University of Nicosia. The first course in their Master of Science in Digital Currency degree, DFIN-511: Introduction to Digital Currencies, is offered for free as an open enrollment MOOC course to anyone interested in learning about the fundamental principles. If you want early-access to talks and a chance to participate in the monthly live Q&As with Andreas, become a patron: https://www.patreon.com/aantonop RELATED: Immutability and Proof-of-Work: The Planetary Scale Digital Monument - https://youtu.be/rsLrJp6cLf4 Consensus Algorithms, Blockchain Technology, and Bitcoin - https://youtu.be/fw3WkySh_Ho Advanced Bitcoin Scripting Part 1: Transactions and Multisig - https://youtu.be/8FeAXjkmDcQ Advanced Bitcoin Scripting Part 2: SegWit, Consensus, and Trustware - https://youtu.be/pQbeBduVQ4I What is Consensus: Rules without Rulers - https://youtu.be/2tqo7PX5Pyc Forkology: A Study of Forks for Newbies - https://youtu.be/rpeceXY1QBM Bitcoin: Where the Laws of Mathematics Prevail - https://youtu.be/HaJ1hvon0E0 The rules of Bitcoin (part 1) - https://youtu.be/VnQu4uylfOs The rules of Bitcoin (part 2) - https://youtu.be/vtIp0GP4w1E Decentralized power, leaderless governance - https://youtu.be/E5VbDlQTPzU Proof-of-Work (PoW), Proof-of-Stake (PoS), Delegated Proof-of-Stake (DPoS) - https://youtu.be/3W_3AQrQEOM Does the Lightning Network have proof-of-stake elements? - https://youtu.be/GOYP4O4yetQ Directed acyclic graphs (DAGs) and IOTA - https://youtu.be/lfgMnbb5JeM Intrinsic vs. extrinsic assets - https://youtu.be/KDtfFNZy9xg Scaling, trust, and trade-offs - https://youtu.be/vCxmHwqyJWU Why running a node is important - https://youtu.be/oX0Yrv-6jVs Running nodes and payment channels - https://youtu.be/ndcfBfE_yoY What happens during a fork? - https://youtu.be/XBk8hBJ1xVo SegWit adoption - https://youtu.be/KCsTVTRk6I4 Energy consumption - https://youtu.be/2T0OUIW89II Solar energy and mining in space - https://youtu.be/cusakcpa8AM Andreas M. Antonopoulos is a technologist and serial entrepreneur who has become one of the most well-known and respected figures in bitcoin. Follow on Twitter: @aantonop https://twitter.com/aantonop Website: https://antonopoulos.com/ He is the author of two books: “Mastering Bitcoin,” published by O’Reilly Media and considered the best technical guide to bitcoin; “The Internet of Money,” a book about why bitcoin matters. THE INTERNET OF MONEY, v1: https://www.amazon.co.uk/Internet-Money-collection-Andreas-Antonopoulos/dp/1537000454/ref=asap_bc?ie=UTF8 [NEW] THE INTERNET OF MONEY, v2: https://www.amazon.com/Internet-Money-Andreas-M-Antonopoulos/dp/194791006X/ref=asap_bc?ie=UTF8 MASTERING BITCOIN: https://www.amazon.co.uk/Mastering-Bitcoin-Unlocking-Digital-Cryptocurrencies/dp/1449374042 [NEW] MASTERING BITCOIN, 2nd Edition: https://www.amazon.com/Mastering-Bitcoin-Programming-Open-Blockchain/dp/1491954388 Subscribe to the channel to learn more about Bitcoin & open blockchains! Music: "Unbounded" by Orfan (https://www.facebook.com/Orfan/) Outro Graphics: Phneep (http://www.phneep.com/) Outro Art: Rock Barcellos (http://www.rockincomics.com.br/)