Bitcoin Q&A: Nonces, Mining, and Quantum Computing
Channel: aantonop
Date: 2018-05-16

Who generates the nonce? What makes it random? How is nonce-guessing important to the competitive process of mining? What happens if the hashing algorithm (SHA-256) was compromised? Is quantum computing a threat?

More on nonces and the mining process: https://github.com/bitcoinbook/bitcoinbook/blob/8ae3c056fb257111bda8883d9d204e8476f9870c/ch09.asciidoc

More about the SHA-1 collision: https://security.googleblog.com/2017/02/announcing-first-sha1-collision.html

More about SHA-1 and Bitcoin: https://bitcoin.stackexchange.com/questions/75135/is-sha-1-used-in-bitcoin

CORRECTION: At 5:53, I described what a collision was. However, the definition I outlined was actually for a pre-image attack, which is distinct from collision attacks. The subtitles have been edited to include the correction. https://en.wikipedia.org/wiki/Preimage_attack

Chapters
0:00 Who generates the nonce? If my pool generates the random number, how is it protected from us knowing it? What makes that random number tamper-proof? Does the whole network contribute to the random number?
1:13 What is the purpose of the nonce?
2:24 When mining, the only part of the header you can change is the nonce
3:50 How do you find one such nonce in five septillion iterations?
5:00 Is it possible to develop a mining algorithm for guessing the nonce, which will fast-track solving the proof-of-work challenge? Could that be related to the recent shattering of the SHA-1 hash algorithm?
10:30 Being a possible threat to the network's security, doesn't this accelerate the race towards building one? Do miners think about this at all?

These questions are from the MOOC 7.2 and 9.2, which took place on February 26th 2017 and February 23rd 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

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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

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