Bitcoin Explained - The Technical Side of Bitcoin

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. --------------------------------------------- Bitcoin Magazine is back in print! Get Bitcoin Magazine shipped directly to your front door! Get 21% off with promo code: MAG21 https://store.bitcoinmagazine.com/discount/MAG21?redirect=%2Fproducts%2Fbitcoin-magazine-annual-subscription   "The Deep Dive" delivers the latest Bitcoin on-chain market intelligence directly to your inbox! Get 1 Month free with promo code: PODCAST https://deepdivebtc.substack.com/01e06e79   Bitcoin 2022 will be the biggest Bitcoin conference ever! Miami, FL from April 6–9, 2022 Get 15% off tickets with promo code: MAG21 https://b.tc/conference/ 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.

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   --------------------------------------------- Bitcoin Magazine is back in print! Get Bitcoin Magazine shipped directly to your front door! Get 21% off with promo code: MAG21 https://store.bitcoinmagazine.com/discount/MAG21?redirect=%2Fproducts%2Fbitcoin-magazine-annual-subscription "The Deep Dive" delivers the latest Bitcoin on-chain market intelligence directly to your inbox! Get 1 Month free with promo code: PODCAST https://deepdivebtc.substack.com/01e06e79 Bitcoin 2022 will be the biggest Bitcoin conference ever! Miami, FL from April 6–9, 2022 Get 15% off tickets with promo code: MAG21 https://b.tc/conference/  

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. --------------------------------------------- Bitcoin Magazine is back in print! Get Bitcoin Magazine shipped directly to your front door! Get 21% off with promo code: MAG21 https://store.bitcoinmagazine.com/discount/MAG21?redirect=%2Fproducts%2Fbitcoin-magazine-annual-subscription   "The Deep Dive" delivers the latest Bitcoin on-chain market intelligence directly to your inbox! Get 1 Month free with promo code: PODCAST https://deepdivebtc.substack.com/01e06e79   Bitcoin 2022 will be the biggest Bitcoin conference ever! Miami, FL from April 6–9, 2022 Get 15% off tickets with promo code: MAG21 https://b.tc/conference/

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.

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.

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!

A Bitcoin Beach special! In this episode of The Van Wirdum Sjorsnado host Aaron van Wirdum speaks with Bitcoin Beach Wallet developer Nicolas Burtey — without cohost Sjors Provoost this time. Aaron and Nicolas met up in El Zonte, El Salvador — which has been dubbed Bitcoin Beach — to discuss the Bitcoin Beach Wallet, a Bitcoin and Lightning wallet specifically designed for use in the small Central American coastal town frequented by surfers and, now, bitcoiners. Aaron and Nicolas discuss the pros and cons of custodial and non-custodial Lightning wallets, and Nicolas explains why he opted to make the Bitcoin Beach Wallet a shared-custodial wallet, and what that means exactly. They go one to discuss some of the design decisions and tradeoffs that the Bitcoin Beach Wallet has made, which include ledger-based payments between Bitcoin Beach Wallet users as well as the webpage-based zero invoice payments to facilitate payments from other Lightning wallets. while Nicolas speculates about a potential cross-wallet user account system to further improve the Lightning user experience over time. Aaron and Nicolas also discuss some of the subtle incompatibilities between different Lightning wallets that use different techniques for routing payments, privacy considerations versus user experience in a community like El Zonte’s, and more.

In this episode of The Van Wirdum Sjorsnado, hosts Aaron van Wirdum and Sjors Provoost are joined by Lightning developer Joost Jager to discuss everything about Lightning Network routing. The Lightning Network — Bitcoin’s Layer Two protocol for fast and cheap payments — consists of a network of payments channels. Each payment channel exists between two Lightning users. But even if two users don’t have a payment channel between themselves directly, they can pay each other though one or several other Lightning users, who in that case forward the payment from the payer to the payee. The challenge is that a payment path across the network must be found, which allows the funds to move from the payer to the payee, and ideally the cheapest, fastest and most reliable payment path available. Joost explains how Lightning nodes currently construct a map of the Lightning Network, and what information about all of the (publicly visible) payment channels is included about in that map. Next, he outlines on what basis Lightning nodes calculate the best path over the network to reach the payee, and how the performance of this route factors into future path finding calculations. Finally, Aaron, Sjors and Joost discuss some (potential) optimizations to benefit Lightning Network routing, such as rebalancing schemes and Trampoline Payments.

In this episode of The Van Wirdum Sjorsnado, hosts Aaron van Wirdum and Sjors Provoost discuss the lock-in of the Taproot soft fork upgrade. As discussed in previous episodes, Taproot is a Bitcoin protocol upgrade that will make smart contracts more compact, private and flexible. Aaron and Sjors also discussed the Taproot upgrade process in prior episodes, including the Speedy Trial activation method adopted by Bitcoin Core. About a week ago, the Speedy Trial signaling threshold was reached, which means Taproot is locked in and will activate later this year. Aaron and Sjors go into further detail about what this means exactly, and what needs to happen before Taproot can ultimately be used on the Bitcoin network safely. Sjors also explains how upcoming Bitcoin Core releases will handle the Taproot upgrade, and what the Bitcoin Core wallet software will and will not enable, while also touching on potential use-cases enabled by the upgrade. Finally, Aaron and Sjors discuss the Speedy Trial activation process itself, and in particular the lessons learned by it, which could in turn inform future soft fork upgrades. They also briefly speculate which protocol upgrades may be next in line.

In this episode of The Van Wirdum Sjorsnado, hosts Aaron van Wirdum and Sjors Provoost explain what Bitcoin Improvement Proposals (BIPs) are, and how the BIP process works. They discuss why the BIP process is a useful, yet non-binding convention within Bitcoin’s technical community. Aaron and Sjors start off by explaining what a BIP is exactly— and what it is not. They also explain that only improvements to Bitcoin software that affects other projects require a BIP. The two go on to dive into the history of the BIP process a little bit, noting that the format was introduced by Libbitcoin developer Amir Taaki and later updated by Bitcoin Knots maintainer Luke-jr. Finally, Aaron and Sjors explain how the BIP process itself works, that is, how a proposal can be turned into a BIP, and eventually be implemented in software. They also briefly explain how the BIP process could become corrupted, and why that wouldn’t be a very big deal. This episode was originally scheduled to be aired on Friday the 4th of June, but was delayed due to last week's Bitcoin 2021 conference in Miami.