IBD libbitcoin approach to IBD - General idea: maximize parallelism - Transaction table, input table, output table - Remove force ordering (caused by UTXO model) - Perform checks whenever a matching input/output pair has arrived - Aggressive on P2P (>100 connections) - Adding a new block to...

We consider the following linear programming formulation for transaction selection: Variables and Objective - Let $f_i$ represent the fee rate of transaction $i$ and $s_i$ represent its size. - Define decision variables $x_i$, where $x_i = 1$ if transaction $i$ is selected, and $x_i = 0$ otherwi...

Tools and Frameworks - **Warnet** - **SimLN** - **Scaling Lightning** - **Polar** - Good for teaching because of the GUI Goals - What's best for research/writing papers - Pressing issue: padding Payment Channel Networks (PCN) Are there any frameworks for PCN besides LN? - **Sprites (?)** -...

How can we achieve the most realistic simulations? - **Ad-hoc Simulations for Individuals**: How can we develop a framework that better suits everyone's needs? Each paper uses its own simulations. It would be better to have a unified solution that is broadly applicable. - The research papers d...

CSV is a way to build a new Layer 1 blockchain - L1 is defined as a transaction protocol, separate from defining consensus/ordering L1 - Bitcoin Tx Verification / CSV L0.5 - Blockchain PoW Recipe 1. Sender prepares a tx 2. Sender derives a nullifier from the tx. Used to nullify the tx input...

Taproot | Benefits | Cost/risks | | -------------------------------------------- | ------------------------------------------------------------ | | Larger anonsets | Easier/cheaper jpe...

In Bitcoin, miners earn from block subsidies and fees. Why is it worrisome when the Bitcoin subsidy is zero? There is an attack possible: undercutting attacks. There is a strong social convention not to undercut, and also the miner subsidy needs to extend the change. If the costs of mining are hig...

Definition of rough consensus How do we define the group to have rough consensus on? For instance, a sub-group could have rough consensus on a proposal just because the largest group of experts isn’t interested in participating. Both groups may have a very different perception of the consensus. Th...

Three Categories of Attacks: 1. **Loss of Funds** 2. **Privacy** 3. **Quality of Service** Brainstorming of Existing Attacks ![Diagram of existing attacks]( - **Jamming** - **Slow** - Proposed solution: Reputation. - **Fast**: Send a large number of HTLCs in a short time. - Propose...

- **Is Activation part of this discussion?** Yes, activation is part of feasibility. - **List upgrades on Sticky Notes** - **Categories** - Consensus cleanup - Total script replacement/alternative - Covenant proposals (discussion of what `lnhance` is) - Various amounts of scr...

Problem description Bitcoin today uses some mempool algorithms that date back to about a decade ago. These algorithms use heuristics which compute the descendent set with the lowest fee rate. The existing algorithms don't address multiple children paying for a parent, or one child paying for multip...

Things (tx construction) that need interaction: - SP - Musig / FROST - Payjoin / Cut Through - CISA - Splicing / LN / Liquid Ads - Atomic Swaps - Coinjoins - DLCs - CT / Bulletproofs - Presigned RBF - BIP322 - WIF / Descriptors - Covenants BIP 370 Modifiability [Link to BIP370]( - Modifiable is...

Why combine Silent Payments and Payjoin? - Silent Payments (SP) are non-interactive, while Payjoin (PJ) is interactive. Both aim to improve privacy. - SP is **stateless**, which means no synchronization or complicated state management. - One SP wallet can be used for multiple protocols, allowing th...

Crash Course - Satoshi: _"If a solution was found [to do ZK with Bitcoin], a much better implementation of Bitcoin would be possible."_ What's Possible - **On-chain:** 12 bytes per transaction in some systems. - **Off-chain:** Any L2 protocol like ARK, coinpools, channel factories. - **Privacy:*...

Discussion Points Is speculating on market behavior in scope? Would it matter if people adopt privacy tools regardless, or would people avoid privacy regardless? - Wants to work on privacy tools that achieve PMF (Product-Market Fit) and substantially move the needle. - Wants to know if there’s a u...

Different privacy topics - HTLC/MPP correlation - Balance Discovery - Intra-LSP payment - Network level attacks - Async Payment privacy - Client Fingerprinting Top 3 list Balance Discovery - Some mitigation by payment splitting - More traffic, more noise? How precise can BDA even be? Network...

Brainstorming (Sticky Notes): - Large holders free-riding security - No more mempool APIs only - All fees are out of band - Mining wars between nation-states - Constant reorgs - Forks (not consensus change) - Race to the bottom between miners sending each other long to validate blocks - No more has...

Avoidable Attack in May 2023: Ordinals Specifics of the attack aren't as important. Issue is that a simple DOS was possible in the wild and it wansn't noticed before it happened. - **Context:** Ordinals/Runes/etc. - **Impact:** Nodes became unresponsive, maxing CPU (DOS-like behavior). - **Cause:...

What would it take to get everyone in the world using Bitcoin? - **Can’t fit every payment on-chain, so need something else:** - Lightning Network, shared UTXOs, sidechains. - **Q: Are we talking about payments or other functionality?** - Mostly payments. - **Layer 2 vs. Sidechain:** - L...

Bitcoin security is based on SHA256 and the discrete log assumption: - GPG keys are used to sign hashes of Bitcoin Core or commits. - There was an alert key. - Some offchain protocols use OMDL (a stronger assumption). Correctness proofs: - Correct, but there are losses in proofs. - You shouldn't ...