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Bitcoin Explained - The Technical Side of Bitcoin

Bitcoin Explained - The Technical Side of Bitcoin

By Van Wirdum Sjorsnado

Bitcoin Magazine's Technical editor Aaron van Wirdum teams up with Bitcoin core contributor Sjors Provoost to explain Bitcoin one episode at a time.
Currently playing episode

Episode 59: Hard Forks (And Whether Bitcoin Has Ever Hard Forked)

Bitcoin Explained - The Technical Side of BitcoinJun 20, 2022

00:00
40:55
Episode 92: Bitcoin Core 27.0

Episode 92: Bitcoin Core 27.0

In this episode of Bitcoin, Explained, Aaron and Sjors explain what new features are included in the upcoming Bitcoin Core 27.0 release.

https://github.com/bitcoin-core/bitcoin-devwiki/wiki/27.0-Release-Candidate-Testing-Guide

===

This episode’s sponsor: ⁠⁠⁠⁠CoinKite⁠⁠⁠⁠, maker of the ColdCard

Aaron's Twitter: ⁠⁠⁠⁠@AaronvanW⁠⁠⁠⁠

Aaron’s Nostr: npub1art8cs66ffvnqns5zs5qa9fwlctmusj5lj38j94lv0ulw0j54wjqhpm0w5

Sjors’ Twitter: ⁠⁠⁠⁠@provoost⁠⁠⁠⁠

Sjors’ Nostr: npub1s6z7hmmx2vud66f3utxd70qem8cwtggx0jgc7gh8pqwz2k8cltuqrdwk4c

If you’d like to sponsor the show, please email info at bitcoinexplainedpodcast.com.

⁠https://bitcoinexplainedpodcast.com/

Apr 10, 202435:40
Episode 91: Splicing
Mar 31, 202442:45
Episode 90: Asynchronous Lightning Payments
Feb 23, 202436:59
Episode 89: B-money and RPOW
Jan 22, 202437:44
Episode 88: Hashcash and Bit Gold
Jan 03, 202445:29
Episode 87: The Block 1,983,702 Problem
Dec 21, 202339:15
Episode 86: Ocean Tides

Episode 86: Ocean Tides



In this episode of Bitcoin, Explained, Aaron and Sjors explain what features are offered by Ocean, the relaunched and rebranded Eligius mining pool. They discuss how payouts from this pool are (partially) non-custodial, how the block template creation is fully transparent, and how payout distribution is determined. Aaron and Sjors also briefly touch on the "spam" filtering employed by Ocean, and how that potentially affects profitability of the pool.

Our new sponsor: https://coinkite.com/

Dec 06, 202336:20
Episode 85: Bitcoin Core 26.0 (And F2Pool’s OFAC Compliant Mining Policy)

Episode 85: Bitcoin Core 26.0 (And F2Pool’s OFAC Compliant Mining Policy)

In this episode of Bitcoin, Explained, Aaron and Sjors explain what new features are included in the upcoming Bitcoin Core 0.26 release. They also briefly discuss recent developments concerning the transaction inclusion policy of mining pool F2Pool, which appears to have been compliant with the OFAC sanctions list.

Link to testing guide: https://github.com/bitcoin-core/bitcoin-devwiki/wiki/26.0-Release-Candidate-Testing-Guide

Nov 23, 202337:19
Episode 84: Marathon Pool’s Invalid Block (And Some Updates About the Show)
Oct 05, 202322:15
Episode 83: The Milk Sad Vulnerability
Aug 17, 202346:48
Episode 82: Scaling to Billions of Users
Jul 11, 202330:29
Episode 81: Bitcoin Core 25.0

Episode 81: Bitcoin Core 25.0

In this episode, Aaron (@AaronvanW) and Sjors (@provoost) discuss Bitcoin Core 25.0, the latest major release of the Bitcoin Core software. They highlight four of the most notable changes: performance improvements concerning huge transaction loads, further Miniscript integration, a faster wallet re-scan, and the decreased 65-byte transaction limit policy rule.


For further reading on the reasoning behind 65-byte policy rule, also see: https://bitslog.com/2018/06/09/leaf-node-weakness-in-bitcoin-merkle-tree-design/


Episode Sponsor: https://voltage.cloud/


Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425


Lower your time preference and lock-in your BITCOIN 2024 conference tickets today! Use the code BMLIVE for a 10% Discount!  - https://b.tc/conference/2024

Jun 26, 202339:02
Episode 80: Stratum V2

Episode 80: Stratum V2

In this episode of Bitcoin, Explained, Aaron (@AaronvanW) and Sjors (@provoost) are joined by Braiins co-founder Jan Čapek (@janbraiins), who has been leading the initiative to upgrade pooled mining to the Stratum V2 protocol. Aaron, Sjors and Jan discuss what pooled mining is, how the Stratum protocol helps with that, and in what ways Stratum V2 is an improvement over Stratum V1.


Episode Sponsor: https://voltage.cloud/

Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425

Lower your time preference and lock-in your BITCOIN 2024 conference tickets today! Use the code BMLIVE for a 10% Discount! - https://b.tc/conference/2024

Jun 13, 202350:00
Episode 79: The Witness Discount

Episode 79: The Witness Discount

In this episode of Bitcoin, Explained, Aaron (@AaronvanW) and Sjors (@provoost) explain why the witness discount was included in the Segregated Witness protocol upgrade from 2017, why this discount is 75%, and why this discount still makes sense in today’s world where Inscriptions benefit from it. Episode Sponsor: https://voltage.cloud/ Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425 Lower your time preference and lock-in your BITCOIN 2024 conference tickets today! Use the code BMLIVE for a 10% Discount! - https://b.tc/conference/2024

May 23, 202349:31
Episode 78: Partially Signed Bitcoin Transactions (PSBTs) (And Dutch Auctions)

Episode 78: Partially Signed Bitcoin Transactions (PSBTs) (And Dutch Auctions)

In this episode of Bitcoin, Explained, Aaron (@AaronvanW) and Sjors (@provoost) explain Partially Signed Bitcoin Transactions (PSBTs), discussing what problems they solve, how they work, and some of the ways they are used. In the last part of the episode, the hosts zoom in on one particular PSBT use case called Dutch Auctions, which Bitcoin Magazine recently used to sell ordinals.


Episode Sponsor: https://voltage.cloud/


Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425


Don't miss out on the biggest Bitcoin event of the year! B23 in Miami is coming up fast, get your tickets now!


Lower your time preference and lock-in your BITCOIN 2023 conference tickets today! Use the code BMLIVE for a 10% Discount!  - https://b.tc/conference/2023

May 08, 202332:57
Episode 77: Peer-to-peer Encryption

Episode 77: Peer-to-peer Encryption

In this episode of Bitcoin, Explained, Aaron and Sjors discuss BIP 324, the proposal by Dhruv, Pieter Wuille and Tim Ruffing to add peer-to-peer (P2P) encryption to the Bitcoin protocol. They explain why this is needed, how it would work, and which problems it would, and wouldn’t solve.


Episode Sponsor: https://voltage.cloud/


Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425


Don't miss out on the biggest Bitcoin event of the year! B23 in Miami is coming up fast, get your tickets now!


Lower your time preference and lock-in your BITCOIN 2023 conference tickets today! Use the code BMLIVE for a 10% Discount!  - https://b.tc/conference/2023

Apr 24, 202336:52
Episode 76: Stamps (And the Invalid Block Caused by It)

Episode 76: Stamps (And the Invalid Block Caused by It)

In this episode of Bitcoin, Explained, Aaron and Sjors explain Stamps, a new(?) protocol to upload images onto the Bitcoin blockchain, which end up in the UTXO set. To learn more about some of the concepts mentioned in this episode, also check out episode 15 (Utreexo), episode 61 (OP_RETURN), episode 72 (Inscriptions) and episode 75 (Multisig). Episode Sponsor: https://voltage.cloud/ Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425 Don't miss out on the biggest Bitcoin event of the year! B23 in Miami is coming up fast, get your tickets now! Lower your time preference and lock-in your BITCOIN 2023 conference tickets today! Use the code BMLIVE for a 10% Discount! - https://b.tc/conference/2023

Apr 15, 202350:53
Episode 75: Multisig (And Musig)

Episode 75: Multisig (And Musig)

In this episode of Bitcoin, Explained, Aaron and Sjors discuss multi-signature (multisig), and the various ways that Bitcoin enables multisig; from bare multisig, to P2SH, SegWit, Taproot, and finally Musig, as well as some potential future solutions.

Episode Sponsor: https://voltage.cloud/

Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425

Don't miss out on the biggest Bitcoin event of the year! B23 in Miami is coming up fast, get your tickets now!

Lower your time preference and lock-in your BITCOIN 2023 conference tickets today! Use the code BMLIVE for a 10% Discount! - https://b.tc/conference/2023

Mar 31, 202352:30
Episode 74: Pay-to-Script-Hash (P2SH)
Mar 17, 202343:24
Episode 73: OP_VAULT

Episode 73: OP_VAULT

In this episode of Bitcoin, Explained, Aaron and Sjors explain OP_VAULT, a proposed op code that would enable an elegant type of vaults through Bitcoin’s scripting language.

For more information, also see:

https://jameso.be/vaults.pdf

https://github.com/bitcoin/bips/blob/c589490f98ba1b0c606d0e2030463f1fde54b786/bip-vaults.mediawiki

===

Episode Sponsor: https://voltage.cloud/

Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425

Don't miss out on the biggest Bitcoin event of the year! B23 in Miami is coming up fast, get your tickets now!

Lower your time preference and lock-in your BITCOIN 2023 conference tickets today! Use the code BMLIVE for a 10% Discount! https://b.tc/conference/2023

Feb 24, 202340:43
Episode 72: Inscriptions

Episode 72: Inscriptions

In this episode of Bitcoin, Explained, Aaron and Sjors explain Inscriptions, a new method to upload arbitrary data onto the Bitcoin blockchain.

Episode Sponsor: https://voltage.cloud/

Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425

Don't miss out on the biggest Bitcoin event of the year! B23 in Miami is coming up fast, get your tickets now!

Lower your time preference and lock-in your BITCOIN 2023 conference tickets today! Use the code BMLIVE for a 10% Discount! https://b.tc/conference/2023

Feb 09, 202340:34
Episode 71: Timelocks

Episode 71: Timelocks

In this episode of Bitcoin, Explained, Aaron and Sjors discuss the different types of timelocks available on Bitcoin (and what can go wrong when used incorrectly).

Episode Sponsor: https://voltage.cloud/

Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425

Lower your time preference and lock-in your Bitcoin 2023 conference tickets today!!! Use promo code BMLIVE to save 10% off your conference tickets today!!!

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Follow us on Twitter:

- https://twitter.com/bitcoinmagazine

- https://twitter.com/videobitcoin

Jan 20, 202332:58
Episode 70: The Bitcoin Core 24.0 Bug (Or Why There Is a Bitcoin Core 24.0.1 Release)

Episode 70: The Bitcoin Core 24.0 Bug (Or Why There Is a Bitcoin Core 24.0.1 Release)

Aaron and Sjors explain how a wallet bug crept into the Bitcoin Core 24.0 release, and why there is now a Bitcoin Core version 24.0.1 available.  

Episode Sponsor: https://voltage.cloud/ 

Sjors New Book: https://www.amazon.com/Bitcoin-Technical-innovations-Sjors-Provoost/dp/9090360425

Lower your time preference and lock-in your Bitcoin 2023 conference tickets today!!! 

Use promo code BMLIVE to save 10% off your conference tickets today!!! https://b.tc/conference/bitcoin2023 

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Dec 30, 202223:04
Episode 69: The Tornado Cash Trial
Dec 02, 202239:30
Episode 68: Full Replace-By-Fee (RBF) in Bitcoin Core 24.0

Episode 68: Full Replace-By-Fee (RBF) in Bitcoin Core 24.0

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost revisit replace-by-fee (RBF). As they mentioned in Bitcoin, Explained episode 65, the upcoming Bitcoin Core release — Bitcoin Core 24.0 — includes the option to switch on “full RBF”, but this has caused some commotion in the Bitcoin community since the recording of that episode. Aaron and Sjors explain what this commotion has been about, and they highlight some of the new arguments for and against (full) RBF.

RBF has been the topic of a previous Bitcoin, Explained episode: episode 26. In this new episode, therefore, Aaron and Sjors don’t explain in-depth on what RBF is, exactly, or how it works. They do however very briefly summarize its most important aspects.

Aaron and Sjors then go on to explain why Bitcoin Core developers originally decided to include this feature, and they discuss some of the arguments for and against (full) RBF that came up at the time and since then. These include the effect of RBF on “pinning attacks” (a type of attack that is especially relevant for the Lightning Network and other Layer Two protocols), the relative safety of accepting unconfirmed transactions today, privacy-related arguments concerning the “opt-in” flag that RBF transactions currently use, the detrimental effects of monitoring the network for potential double spends, and more.   Aaron and Sjors also discuss the pros and cons of including RBF as an optional feature and thus letting node operators decide for themselves how their node deals with conflicting unconfirmed transactions. Sjors outlines why, in some cases, giving users more options could have detrimental effects on the health of the Bitcoin network, and considers whether the option to include the RBF option is such a case.   Finally, Aaron and Sjors briefly discuss an initiative by full RBF advocate Peter Todd to incentivize miners to apply full RBF logic to their transaction selection.  

THIS EPISODE’S SPONSORS:

Voltage - https://voltage.cloud/

Bitcoin 2023 Miami - https://b.tc/conference/

Bitcoin Magazine - https://store.bitcoinmagazine.com/

Bitcoin Magazine Pro - https://bitcoinmagazine.com/tags/bitcoin-magazine-pro

 

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Nov 18, 202242:52
Episode 67: Insights From the Fourth Largest Lightning Network Node

Episode 67: Insights From the Fourth Largest Lightning Network Node

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost speak with Sam Wouters, a research analyst at River Financial. River operates the fourth largest node on the Lightning network, and Sam recently published a report detailing unique insights from this Lightning node.

At the start of the episode, Sjors first gives a brief update on the bug that brought down LND nodes, discussed in episode 66. He confirms that his assessment of the cause was correct, and explains that a very similar bug has brought down LND once more since recording of the last episode.

Aaron and Sjors then go on to ask Sam about the contents of his report, with a focus on three subsections of the report in particular.

First, Aaron, Sjors and Sam discuss the current status of fees and liquidity. Sam explains that large Lightning nodes can earn a “return on investment” of several percentages per year by routing payments over the network, but that this does require active channel maintenance to manage liquidity.   Second, Aaron, Sjors and Sam discuss why some Lightning payments fail. Sam explains that the success rate of Lightning payments is very high compared to just a few years ago, but that there are two main reasons why payments sometimes do still fail: payment timeouts, and a lack of available routes. The trio speculates why this might be the case.

Lastly, Sam outlines some of the challenges and concerns related to running Lightning infrastructure for businesses.  

THIS EPISODE’S SPONSORS:

Voltage - https://voltage.cloud/

Bitcoin 2023 Miami - https://b.tc/conference/

Bitcoin Magazine - https://store.bitcoinmagazine.com/

Bitcoin Magazine Pro - https://bitcoinmagazine.com/tags/bitcoin-magazine-pro

 

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Nov 07, 202250:46
Episode 66: The BTCD Bug That Brought Down LND Nodes

Episode 66: The BTCD Bug That Brought Down LND Nodes

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost discuss a recent bug in the btcd Bitcoin implementation that affected a large part of the Lightning network, as it disconnected lnd Lightning nodes from the Bitcoin blockchain.

 

In the episode, Aaron and Sjors explain that a developer going by the name Burak on Twitter created a 998-of-999 multisig transaction by leveraging Taproot. Although this was a valid transaction, btcd and lnd nodes rejected it, and therefore rejected the block that included the transaction and all blocks that came after it.

 

Specifically, Sjors explains, btcd rejected the transaction because it has a maximum limit on how much witness data a Segwit transaction can include. Although other Bitcoin implementations do enforce this limit on Segwit version 0 transactions, Segwit version 1 (that is, Taproot) transactions have no such limit.

 

Still, it is a bit unclear why this bug in btcd seemingly also affected many lnd Lightning nodes which use Bitcoin Core rather than btcd to validate blocks. In the second half of the episode, Sjors speculates how the two may be connected.

 

Finally, Aaron and Sjors explain how the Lightning Network is affected when Lightning nodes reject the Bitcoin blockchain.

 

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Oct 21, 202233:34
Episode 65: Bitcoin Core 24.0

Episode 65: Bitcoin Core 24.0

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost discuss the upcoming Bitcoin Core major release, Bitcoin Core 24.0.

The Bitcoin Core project produces a new major release of its software roughly every six months. The 24th major release is currently in its release candidate phase, which means that it is being tested and could technically be released any day now (though this phase will probably last a few more weeks). In the episode, Aaron and Sjors discuss seven of the most notable changes included in Bitcoin Core 24.0.   This includes a change to how nodes download blocks when they sync with the network. While previous Bitcoin Core versions already started by downloading only block headers to make sure that the blocks they download have sufficient proof of work on them, Bitcoin Core 24.0 nodes will initially not store these block headers in order to prevent a certain type of resource exhaustion attack. Aaron and Sjors explain that this should eventually also allow for the removal of any checkpoints in the Bitcoin Core codebase.   They go on to explain that Bitcoin Core 24.0 also includes an added option for users to apply full replace-by-fee (RBF) logic. Where Bitcoin Core nodes so far would apply the “first seen” rule, which meant that conflicting transactions wouldn’t be accepted in the node's memory pool (mempool) and forwarded to peers, Bitcoin Core 24.0 users can choose to make their nodes accept and forward conflicting transactions if they include a higher fee than (the) earlier transaction(s) they conflict with.   Further upgrades discussed by Aaron and Sjors include a tool to migrate legacy wallets to descriptor wallets, initial miniscript support, default use of RBF when creating transactions, an improved UTXO selection algorithm which randomizes change output amounts for extra privacy, and a new “send all” function to spend a particular (set of) UTXO(s) in full.  

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Oct 07, 202241:36
Episode 64: HD Wallets, Mnemonic Codes and SeedQR

Episode 64: HD Wallets, Mnemonic Codes and SeedQR

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost discuss Hierarchical Deterministic (HD) Wallets, mnemonic codes, and — especially — the new SeedQR format which allows users to store their mnemonic codes as QR codes.

Aaron and Sjors start the episode by recapping what HD Wallets (also known as private key seeds) are, and why they are preferred over regular private key backups. Next, they briefly explain why mnemonic codes (also known as seed phrases) are a popular solution for encoding and storing private key seeds.

The Bitcoin, Explained hosts then go on to discuss SeedQR. SeedQR is a new format that allows Bitcoin users to encode and store their mnemonic code as a QR code. This means that mnemonic codes can be stored in a computer-readable format; any compatible device (like a hardware wallet with a camera) should be able to scan the QR code, and import all associated private keys.

This could be useful for backups. but it could also be used so that wallets (including hardware wallets, but also mobile or desktop wallets) no longer have to store private keys at all. The QR code could be scanned when the wallet is used to send a transaction, after which the private keys could be forgotten by the device altogether. (SeedSigner is an open source, do-it-yourself hardware wallet that does exactly this.)

Finally, Sjors goes over some of the intricacies of formatting a seed phrase to fit in a compact QR code, and some of the efficiency gains SeedQR uses to accomplish this.

 

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#BitcoinExplained #BitcoinPrice #BitcoinCore #BitcoinMagazine #journalism  #bitcoinnews

Sep 19, 202229:26
Episode 63: The Bitcoin Core Development Process

Episode 63: The Bitcoin Core Development Process

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost discuss the Bitcoin Core development process, and more specifically, the different roles that are involved in this process.

At the start of the episode, Aaron and Sjors explain what Bitcoin Core is, both in a practical sense as well as in a more definitional sense, and they touch on some slightly different ideas about this as well.

Aaron and Sjors then go on to explain the roles of three distinct types of Bitcoin Core contributors: “regular” Bitcoin Core contributors, Bitcoin Core maintainers, and the Bitcoin Core lead maintainer.

Since there are no barriers to entry, anyone can become a Bitcoin Core contributor, Aaron and Sjors point out: anyone can start contributing to the Bitcoin Core project by offering code, review of code, or perhaps other types of contributions like text translations.

Bitcoin Core maintainers, then, are Bitcoin Core contributors who can merge new code into the Bitcoin Core codebase. Aaron and Sjors explain what this means exactly, and how someone can become a Bitcoin maintainer.

Finally, Aaron and Sjors go over some of the typical tasks of the Bitcoin Core lead maintainer, which includes managing the release process, adding and removing (other) Bitcoin Core maintainers to the project, and updating the bitcoincore.org website. They also discuss which of these tasks are in fact still done by the Bitcoin Core lead maintainer, however, and which tasks have over the years become more distributed.

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Sep 02, 202239:55
Episode 62: Hash Functions

Episode 62: Hash Functions

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost go back to basics. They explain one of the most fundamental building blocks in all of Bitcoin: hash functions.

To start the episode off, Aaron and Sjors explain that hash functions are a type of mathematical one-way functions. That means that they can easily convert one piece of data into another piece of data, a hash, but anyone who knows only this hash can not convert it back to the original data. Additionally, a hash is supposed to be unique: no two (different) pieces of data should result in the same hash. If either of these things is no longer true, a hash function is considered to be broken.

Then, Aaron and Sjors go on to explain in a little bit more detail how hash functions actually work. They discuss some aspects of the history and evolution of different hash functions, they mention some hash functions that have indeed been broken over time, and they pinpoint which hash functions are used in Bitcoin.

Finally, Aaron and Sjors explain how hash functions are used in Bitcoin, exactly. This includes almost every aspect of the Bitcoin system, they point out, ranging from transactions (in multiple ways) and blocks, to addresses and the proof of work mechanism, as well as in relatively new upgrades like Taproot, and hash functions are even used to create some randomness needed to establish connections on the peer-to-peer network.

Aug 12, 202235:48
Episode 61: OP_RETURN (And the ‘OP_RETURN Wars’)

Episode 61: OP_RETURN (And the ‘OP_RETURN Wars’)

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost discuss OP_RETURN and what some have called the “OP_RETURN wars”. More specifically, they discuss a blog post by BitMEX research titled: “The OP_Return Wars of 2014 – Dapps Vs Bitcoin Transactions”.

Aaron and Sjors start off by explaining that OP_RETURN is an op code (a piece of code for Bitcoin transactions) that will render invalid any transaction that includes it in an input. This means that outputs that include OP_RETURN are unspendeable, which in turn means that Bitcoin nodes can safely remove such UTXOs from their UTXO set, which safes on storage.

Early in Bitcoin’s years, people started using Bitcoin for more than just transactions. As one example given by Sjors, someone uploaded the entire Bitcoin white paper onto the blockchain. The BitMEX blog meanwhile explains that Layer Two protocols like Counterparty were rolling out decentralized applications on the blockchain. This type of non-transaction data was initially embedded in multisig transactions, but this meant that all Bitcoin nodes had to download, process and store this data forever, which comes at a cost.

To mitigate this problem, Aaron and Sjors explain, Bitcoin developers in 2014 agreed to let nodes process and forward transactions with OP_RETURN outputs. These transactions would be better for uploading data, since their outputs can be removed form the UTXO set.

The “OP_RETURN wars” refer to a debate between Bitcoin developers and (most notably) Counterparty developers over the maximum size of such transactions. Sjors explains why the maximum of 40 bytes was initially choses, why this was later increased to 80 bytes, and how these considerations have changed over time.

BitMEX’ blog post: https://blog.bitmex.com/dapps-or-only-bitcoin-transactions-the-2014-debate/

Sjors’ book mentioned in the episode: https://www.btcwip.com/

Evan Kaloudis tells P & Q what hyperbitcoinization means to him.

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#bitcoin #bitcoinmagazine #hyperbitcoinization #money #whatismoney #whatisbitcoin #crypto #cryptocurrencies #globalmarkets

Jul 15, 202226:17
Episode 60: Reusing Addresses (and the Hertzbleed Attack)

Episode 60: Reusing Addresses (and the Hertzbleed Attack)

Jul 01, 202233:10
Episode 59: Hard Forks (And Whether Bitcoin Has Ever Hard Forked)
Jun 20, 202240:55
Episode 58: Silent Payments

Episode 58: Silent Payments

In this episode of <em>Bitcoin, Explained</em>, hosts Aaron van Wirdum and Sjors Provoost welcome Ruben Somsen back on the show to talk about a recent proposal of his called “Silent Payments”. Silent Payments resemble earlier ideas like Stealth Addresses and Reusable Payment Codes, in that they allow users to publish a static “address”, while this is not the actual Bitcoin address they will be paid on. Instead, senders of a transaction can use this static address to generate new Bitcoin addresses for the recipient, for which the recipient — and only the recipient — can in turn generate the corresponding private keys. Like Stealth Addresses and Reusable Payment Codes, the benefit of Silent Payments is that addresses can be posted publicly without harming users’ privacy; snoops cannot link the publicly posted address to the actual Bitcoin addresses that the recipient is paid on. Meanwhile, unlike Stealth Addresses and Reusable Payment Codes, Silent Payments do not require any additional blockchain data— though this does come at a computational cost for the recipient. The podcast episode details all this in roughly two parts. In the first half of the episode, Ruben, Aaron and Sjors break down how Silent Payments work, and in the second half of the episode they discuss how Silent Payments compare to Stealth Addresses and Reusable Payment Codes, as well as some potential implementation issues.
Jun 10, 202246:17
Episode 57: User Rejected Soft Forks (URSFs)

Episode 57: User Rejected Soft Forks (URSFs)

In this episode of <em>Bitcoin, Explained</em>, hosts Aaron van Wirdum and Sjors Provoost discuss URSFs, which stands for either User Rejected Soft Forks or User Resisted Soft Forks, depending on who you ask. URSFs are a recently introduced tool in Bitcoin’s upgrade mechanism toolkit.<br /> <br /> In the first part of the episode, Aaron and Sjors explain that URSFs are best considered the mirror equivalent of UASFs (User Activated Soft Forks) with mandated signaling. Where UASFs will towards the end of a soft fork activation window reject blocks that don’t signal readiness for a soft fork, URSFs will reject blocks that <em>do </em>signal. If both UASF and URSF clients are deployed, they would in principle create a split in the blockchain.<br /> <br /> In the second part of the episode, the duo outlines the various soft fork upgrade mechanisms, ranging from MASFs (Miner Activated Soft Forks), flag day activated UASFs and mandated signaling UASFs. Aaron then explains why he believes mandated signaling UASFs are his preferred method of deploying soft forks, and why he thinks URSFs should in the future be offered as an added option for users who prefer to reject the soft fork.<br /> <br /> Finally, Sjors lays out the “rough consensus” guidelines as used in context of the Internet Engineering Taskforce (IETF), and how this applies to Bitcoin upgrades.
May 06, 202243:42
Episode 56: Bitcoin Core 23.0

Episode 56: Bitcoin Core 23.0

In this episode of <em>Bitcoin, Explained</em>, hosts Aaron van Wirdum and Sjors Provoost discuss Bitcoin Core 23.0, the upcoming major release of Bitcoin's de facto reference implementation. The duo highlights some of the most notable changes in this new software client, and they offer a bit of extra context about the release as well.<br /> <br /> At the time of recording this episode, Bitcoin Core 23.0 was still going through the release candidate phase, where the software is tested for bugs; Aaron and Sjors start by explaining how this process works, exactly.<br /> <br /> Then, throughout the episode, Aaron and Sjors highlight seven changes that are included in this new Bitcoin Core release: 1) the removal of the preference to connect with peers through port 8333, 2) the added support for CJDNS, 3) the inclusion of replace-by-fee transactions in the transaction fee estimation algorithm, 4) the inclusion of statically defined tracepoints, 5) a new tool to spot typos in bech32 addresses, 6) the addition of support for Taproot in the wallet, and 7) the new option to freeze certain UTXOs until some time in the future.<br /> <br /> Finally, Aaron and Sjors discuss how a bug in a software compiler had initially resulted in a bug in an earlier version of this Bitcoin Core release for Windows, giving an interesting insight in the complications with upstream dependencies.
Apr 25, 202234:54
Episode 55: Syncing Old Nodes
Mar 25, 202237:07
Episode 54: Burying Soft Forks

Episode 54: Burying Soft Forks

In this episode of <em>Bitcoin, Explained</em>, hosts Aaron van Wirdum and Sjors Provoost revisit the Taproot activation saga, this time to discuss burying of soft forks. Taproot, the last soft fork to have been deployed on the Bitcoin network, activated in late 2021. Now, Bitcoin Core developers are considering to “bury” the soft fork, which means that future Bitcoin Core releases will treat Taproot as if the rule change has been active since Bitcoin’s very beginning. (With the exception of one block mined in 2021 that breached the Taproot rules which have since been added to the protocol.) In the episode, Sjors explains what the benefits are of burying a soft fork, in particular pointing out how it helps developers when they review the Bitcoin Core codebase or when they perform tests on it. After that, Aaron and Sjors outline a potential edge case scenario where burying soft forks could, in a worst-case scenario, split the Bitcoin blockchain between upgraded and non-upgraded nodes. Bitcoin Core developers generally don’t consider this edge case — a very long block re-org — to be a realistic problem and/or believe that this would be such a big problem that a buried soft fork would be a minor concern comparatively. However, they explain, not everyone agrees with this assessment entirely…<br /> <br /> Finally, Aaron and Sjors touch on issues like whether soft fork activation logic should itself be considered a soft fork, and whether soft fork burying logic should be considered a consensus change and/or require a Bitcoin Improvement Proposal (BIP).
Feb 25, 202237:05
Episode 53: Discreet Log Contracts (DLCs)

Episode 53: Discreet Log Contracts (DLCs)

In this episode of <em>Bitcoin, Explained</em>, hosts Aaron van Wirdum and Sjors Provoost are joined by resident sidechain and Layer Two expert Ruben Somsen again, this time to discuss Discreet Log Contracts (DLCs).<br /> <br /> Discreet Log Contracts are a type of smart contracts for Bitcoin, first proposed by Lightning Network white paper coauthor Tadge Dryja. In essence, DLCs are a way to perform bets— but this means that they can ultimately be leveraged for all sorts of financial instruments, including futures markets, insurances and stablecoins.<br /> <br /> At the start of the episode, Aaron, Sjors and Ruben discuss what can be considered a type of proto-DLC, namely a multi-signature setup for sports betting where two participants add a neutral third party (an “oracle”) that can resolve the bet one way or the other if needed. The trio explains, however, how this solution comes with a number of downsides, like the difficulty of scaling it.<br /> <br /> From there, Aaron, Sjors and Ruben go on to explain how DLCs solved these problems using a setup that resembles payment channels as used on the Lightning Network. When structured like this, they explain, oracles merely need to publish a cryptographically signed message about the outcome of an event, which can be used by the winning participant of the bet to create a withdrawal transaction from the payment channel. Finally, Ruben explains how the original DLC concept could be streamlined by using adaptor signatures, a sort of “incomplete signatures” that can be made complete using the signed message from the oracle. With adaptor signatures, DLCs no longer require a separate withdrawal transaction, as the winner can claim funds from the payment channel directly.
Feb 11, 202252:02
Episode 52: Federated eCash

Episode 52: Federated eCash

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost are once again joined by resident sidechain and Layer Two expert Ruben Somsen, this time to discuss Federated Ecash, a project that has since October 2021 been sponsored by Bitcoin infrastructure company Blockstream.

In the episode, Aaron, Sjors and Ruben discuss the history and design of Ecash, a pioneering digital cash project developed by cryptographer David Chaum and his startup Digicash in the early 1990s. The trio explains how the Ecash system allowed customers of regular banks to make private transactions over the internet.

This latest iteration of Ecash, Federated Ecash, takes the original concept, but applies it to be utilized by custodial (or shared custodial) Bitcoin and Lightning wallets. In short, a Federated Ecash service would accept bitcoin deposits, and exchange them for bitcoin-denominated Ecash tokens. These tokens can be send to other users, and ultimately redeemed for the deposited bitcoin. These bitcoin would, in the mean time, be locked up in a multisig address shared between a set of custodians.

Concluding the episode, Aaron, Sjors and Ruben go over a short list of ideal properties for a digital cash system, and asses how Bitcoin, Ecash, and the combination of the two embed these properties.

Jan 14, 202244:53
Episode 51: Compact Blocks

Episode 51: Compact Blocks

Hosts Aaron van Wirdum and Sjors Provoost are back from their travel break for a brand new episode of Bitcoin, Explained! In this episode, they explain how Bitcoin’s peer-to-peer network is made more efficient and fast with Compact Blocks.<br /> <br /> Compact blocks are — as the name suggests — compact versions of Bitcoin blocks, that have been used by Bitcoin Core nodes since version 0.13. Compact Blocks contain the minimal amount of data required for Bitcoin nodes to reconstruct entire blocks. Most notably, Compact Blocks exclude most transaction data, to instead include short transaction identifiers. Bitcoin nodes can use these short identifiers to figure out which transactions from their mempools should be included in the blocks.<br /> <br /> Aaron and Sjors explain how and why Compact Blocks benefit the Bitcoin network, and specifically how they help counter mining centralization. The hosts also cover some edge cases that can result from the use of Compact Blocks — like the possibility that different valid transactions can have an identical identifier — and how Bitcoin nodes handle such occurrences. Finally, Sjors briefly touches on some of the ongoing improvements that have been added to the Compact Blocks protocol since it was first introduced.
Dec 31, 202118:05
Episode 50: The Mempool (And Why We Need It)

Episode 50: The Mempool (And Why We Need It)

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost discuss a recent thread on the Bitcoin development mailing list, titled “Death to the Mempool, Long Live the Mempool”.   In the thread, Blockstream engineer Lisa “niftynei” Neigut proposes to get rid of the memory pool (mempool): the collection of unconfirmed transactions that Bitcoin nodes use to share transactions over the network, and that Bitcoin miners use to create new blocks from. She argues that the Bitcoin system could be drastically simplified if users instead just send their transactions directly to miners (or mining pools).

In the episode, Aaron and Sjors explain how this would work, and why this is not as simple as it may sound. Based on the responses in the thread, they go over the reasons why getting rid of the mempool is in fact not a very good solution for a system like Bitcoin. Specifically, they discuss the implications on mining privacy and decentralization, while also exploring some other tradeoffs that would need to be made in order to make the Bitcoin system work without a mempool.   Finally, Sjors considers an idea that Aaron doesn’t understand.  

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Nov 27, 202139:16
Episode 49: The Attack of the Fake Peers!

Episode 49: The Attack of the Fake Peers!

Bitcoin was under attack! It’s the story the mainstream media won’t tell you!

 

Hosts Aaron van Wirdum and Sjors Provoost finally met in Utrecht again to record Bitcoin, Explained. In this episode, they discuss a recent attack on the Bitcoin network, where some nodes were flooding peers with fake IP-addresses.

 

As previously discussed in episode 13, Bitcoin nodes connect to peers on the network through IP-addresses, which they learn from their existing peers. Nodes on the network essentially share the IP-addresses of other nodes.

 

Recently, however, some Bitcoin nodes shared large amounts of IP-addresses that weren’t associated with real Bitcoin nodes at all. While this attack did not do very much damage, it did waste resources from nodes on the network. On top of that, Aaron and Sjors explain, the attack could offer the attacker insight into Bitcoin’s network topology by analyzing how the fake IP-addresses spread through the network.

 

Finally, Aaron and Sjors discuss how the attack was solved by rate limiting the amount of IP-addresses than any node will allow its peers to be shared. Further, they consider how in free and open source software development, fixing problems is not always as straightforward as it may seem…

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Nov 12, 202120:50
Episode 48: SIGHASH_ANYPREVOUT and Eltoo part 2

Episode 48: SIGHASH_ANYPREVOUT and Eltoo part 2

In this episode of “Bitcoin Explained,” host Sjors Provoost and guest Christian Decker discussed SIGHASH_ANYPREVOUT, a proposed new sighash flag that would enable a cleaner version of the Lightning Network and other Layer 2 protocols.

Sighash flags are included in Bitcoin transactions to indicate which part of the transaction is signed by the required private keys, exactly. This can be (almost) the entire transaction, or specific parts of it. Signing only specific parts allows for some flexibility to adjust the transaction even after it is signed, which can sometimes be useful.

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Decker and Provoost explained that SIGHASH_ANYPREVOUT is a new type of sighash flag, which would sign most of the transaction, but not the inputs. This means that the inputs could be swapped, as long as the new inputs would still be compatible with the signature.

SIGHASH_ANYPREVOUT would be especially useful in the context of Eltoo, a proposed Layer 2 protocol that would enable a new version of the Lightning Network. In place of how Lightning users currently need to store old channel data for security reasons, and could also be punished severely if they accidentally broadcast some of this data at the wrong time, Decker and Provoost explained how SIGHASH_ANYPREVOUT would do away with this requirement.

Oct 29, 202132:26
Episode 47: Lightning Network Payment Flows

Episode 47: Lightning Network Payment Flows

In this episode of Bitcoin Explained, (formerly known as The Van Wirdum Sjorsnado) host Sjors Provoost is joined by Rene Pickhardt to discuss Rene’s paper “Optimally Reliable & Cheap Payment Flows on the Lightning Network”. Rene has spent the last two years researching the reliability of the lightning network, and the reliability of the payment process. They discuss the design principles of the lightning network, the difficulties with routing payments on lightning, probing channel balances, and much more.   Rene's Paper: https://arxiv.org/abs/2107.05322  

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Oct 15, 202127:22
Episode 46: The Chivo App (First Look)

Episode 46: The Chivo App (First Look)

In this episode of Bitcoin, Explained (formerly known as The Van Wirdum Sjorsnado) hosts Aaron van Wirdum and Sjors Provoost discuss the Chivo application, the Bitcoin wallet, and payment terminal provided by the government of El Salvador. This episode is a little bit different from other episodes of Bitcoin, Explained, because the Chivo app is closed source software. Instead of analyzing the source code and design of the application, Aaron and Sjors have to rely on Aaron’s personal experience with the wallet and payment terminal or what he remembers of that personal experience. The episode opens with some general information about the Chivo Wallet, like why it was developed and who developed it (insofar anything is known about that). Aaron and Sjors go on to discuss Aaron’s experiences with the wallet and speculate what that means for the design. After that, they discuss the design of the payment terminal that’s included in the application, and also briefly touch on the Chivo ATMs that have been deployed across the country. Finally, Aaron and Sjors discuss the difference in philosophy between the design of the Chivo application and Bitcoin’s free and open-source software culture.

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Oct 11, 202153:18
Episode 45: Bitcoin Core 22.0

Episode 45: Bitcoin Core 22.0

The Van Wirdum Sjorsnado has rebranded, and is now called Bitcoin, Explained!

In this episode of Bitcoin, Explained, hosts Aaron van Wirdum and Sjors Provoost discuss Bitcoin Core 22.0, the latest major release of the Bitcoin Core software client, currently the de facto reference implementation of the Bitcoin protocol. Aaron and Sjors highlight several improvements to the Bitcoin Core software.

The first of these is hardware wallet support in the graphical user interface (GUI). While hardware wallet support has been rolling out across several previous Bitcoin Core releases, it is now fully available in the GUI. The second highlighted upgrade is support for the Invisible Internet Project (I2P), a Tor-like internet privacy layer. Aaron and Sjors also briefly touch on the differences between I2P and Tor.

The third upgrade discussed in the episode is Taproot support. While Taproot activation logic was already included in Bitcoin Core 0.21.1 Bitcoin Core 22.0 is the first major Bitcoin Core release ready to support Taproot when it activates this November, and includes some basic Taproot functionality.

The fourth upgrade that Aaron and Sjors discuss is an update to the testmempoolaccept logic, which paves the way to a bigger package relay upgrade. This could in a future release allow transactions to be transmitted over the Bitcoin network in packages including several transactions at the same time.

Additionally, Aaron and Sjors briefly discuss an extension to create multisig and add multisig address, the new NAT-PMP option, and more.

Sep 13, 202132:38
Episode 44: BOLT 12

Episode 44: BOLT 12

Sjors is back!

In this episode of The Van Wirdum Sjorsnado, hosts Aaron van Wirdum and Sjors Provoost discuss BOLT 12 (Basis of Lightning Technology 12), a newly proposed Lightning Network specification for “offers”, a type of “meta invoices” designed by c-lightning developer Rusty Russell.

Where coins on Bitcoin’s base layer are sent to addresses, the Lightning network uses invoices. Invoices communicate the requested amount, node destination, and the hash of a secret which is used for payment routing. This works, but has a number of limitations, Sjors explains, notably that the amount must be bitcoin-denominated (as opposed for fiat denominated), and the invoice can only be used once.

BOLT 12, which has been implemented in c-ligtning, is a way to essentially refer a payer to the node that is to be paid, in order to request a new invoice. While the BOLT 12 offer can be static and reusable — it always refers to the same node — the payee can generate new invoices on the fly when requested, allowing for much more flexibility, Sjors explains.

Finally, Aaron and Sjors discuss how the new BOLT 12 messages are communicated over the Lightning Network through an update to the BOLT 7 specification for message relay.

Aug 13, 202130:36
Episode 43: Hardware Wallets and Blockstream’s Jade Wallet

Episode 43: Hardware Wallets and Blockstream’s Jade Wallet

In this episode of The Van Wirdum Sjorsnado, Aaron van Wirdum hosts one more interview without his regular cohost Sjors Provoost. Instead, he is joined by Blockstream’s Lawrence Nahum, one of the developers behind the Jade wallet, and Ben Kaufman, one of the developers of the Spectre wallet, which is specifically designed to work with hardware wallets.

Aaron, Lawrence and Ben talk about what hardware wallets are, and discuss the design tradeoffs that different hardware wallets have taken by focussing on the Trezor, Ledger and ColdCard specifically. In this light, Lawrence and Ben explain what secure elements and secure chips are, and why some hardware wallets choose to rely on using such chips more than others.

Then, Lawrence explains which tradeoffs the Jade wallet makes. He also details how an additional server-based security step is used to further secure the Jade wallet, and briefly outlines some additional differences in hardware wallet designs, for example those focused on usability.

Finally, Aaron, Lawrence and Ben discuss whether the concept of hardware wallets are a good idea in the first place, or if it would perhaps be better to use dedicated smartphones to store your bitcoin.

And don’t worry, Sjors will be back for episode 44!

Jul 30, 202152:26