Bitcoin Q&A: Public Keys vs. Addresses

What is the difference between public keys and addresses? How are new addresses generated? How are change addresses generated? Why have two outputs? Do you still pay fees if you are sending bitcoin to new addresses in your own wallet? What is the VanityGen command? What does the SIG_HASH flag do? More from 'Mastering Bitcoin': https://github.com/bitcoinbook/bitcoinbook/blob/f8b883dcd4e3d1b9adf40fed59b7e898fbd9241f/ch04.asciidoc Chapters 0:00 What is the difference between public keys and addresses? 0:57 If my wallet automatically generates a new address for each transaction, will bitcoin previously sent to me on a different address be transferred to the new address just generated? If someone is going to send me funds to a previously-used address, will I still receive them? 3:54 How can we generate a new address to receive change? 4:17 Why not have a single output with the exact amount of BTC, instead of two outputs, one of which is change? 5:17 Do transactions with multiple inputs and one output pay a fee, even if the wallet is just reorganizing funds? 7:00 Can you explain the VanityGen command? What is a vanity address? 10:55 SIGHASH_ALL is for signing all inputs and outputs. How can all inputs be signed with one signature, when each of the inputs have a different private key? These questions are from the MOOC 9.3 and 9.5 sessions which took place on March 2nd and March 16th, 2018 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: Advanced Bitcoin Scripting Part 1: Transactions and Multi-sig - https://youtu.be/8FeAXjkmDcQ Advanced Bitcoin Scripting Part 2: SegWit, Consensus, and Trustware - https://youtu.be/pQbeBduVQ4I Reusing addresses - https://youtu.be/4A3urPFkx8g Airdrop coins and privacy implications - https://youtu.be/JHRnqJJ0rhc Wealth distribution statistics - https://youtu.be/X2Qsz4eaSPY Mixing services - https://youtu.be/rKoMvOH4zoY How do mnemonic seeds work? - https://youtu.be/wWCIQFNf_8g Using paper wallets - https://youtu.be/cKehFazo8Pw What is Segregated Witness? - https://youtu.be/dtOjjB4mD8k Spam transactions and Child Pays For Parent (CPFP) - https://youtu.be/t3c0E4fkSNs 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/) Join the aantonop Channel: https://aantonop.io/joinaantonopyt