Author: sjors

Van wie is deze bitcoin? This post is in Dutch. The short English version is in this Twitter thread: You may want to turn off transaction email notifications, and ask your favorite wallet provider to use PGP. In general email notications are a big privacy / security risk; they form a detailed record of stuff that's… Continue reading Van wie is deze bitcoin?

Bitcoin on an Orange Pi (using Armbian) There are some good articles on how to run a Bitcoin Core full node on a Raspberry Pi. But there are other pies, some of which have better performance. That’s great news, because the Bitcoin blockchain has grown a lot recently, so any extra CPUs, RAM and storage are… Continue reading Bitcoin on an Orange Pi (using Armbian)

Bitcoin Core + Lightning + Rails on AWS Recently I’ve been working on a project code-named Matreon. It’s like Patreon, but for the matriarchy. In a world of increasing online censorship, being able to host your own website and process your own payments really helps. Step 1: your fans pick a monthly amount to contribute Step… Continue reading Matreon: Bitcoin Core + Lightning + Rails on AWS

Bitcoin Core Wishlist I started to contribute code and reviews to Bitcoin Core a few months ago and gradually accumulated lists of stuff I’d like to see. Some of these I can do myself, others are still beyond my level of expertise, still others might be terrible ideas and never happen.

Decoding a BIP-70 Payment Request I was trying to understand BIP-70 Payment Requests a bit better, mainly because I am confused by BitPay’s claim that they can somehow block “mistaken” transactions: We can also analyze transactions to make sure an adequate bitcoin miner fee is included. If the fee isn’t sufficient to allow the transaction to… Continue reading Decoding a BIP-70 Payment Request

On Fees When sending less than €1,000 of Bitcoin it’s worth paying attention to fees, but keep mind that your payment is competing with transactions that move €100,000 on equal terms. Transactions are charged per byte, not as a percentage of the amount. But willingness to pay is obviously a percentage of the amount. It’s… Continue reading On Fees

I was trying to improve the functional tests for bumpfee, a Bitcoin Core wallet feature that lets you increase the fee of a transaction that’s unconfirmed and stuck. Unfortunately I introduced a bug in the test, which I’m still in the process of tracking down. Every disadvantage has its advantage, so I took the opportunity… Continue reading Debugging Bitcoin Core Functional Tests

A Short History of Replay Protection This article is based on the slides I used for a presentation at the Hong Kong Bitcoin Developer meetup on November 1st, plus some feedback I received on the chainspl.it Slack. This was before SegWit2x was called off, but in the interest of (my) time, I haven’t adjusted this… Continue reading A Short History of Replay Protection

Opt-in hard-fork without alternate transaction history? IETF’s RFC 7282 is an eloquent document which describes important aspects on koop consensus, and worthwhile if you want a more nuanced interpretation than “widespread agreement and disagreements addressed (even if not acommodated)”. Measuring Consensus Once we have a concrete technical proposal, and it seems to have some traction,… Continue reading Opt-in hard-fork without alternate transaction history?

Replay Protection in The Blockchain Wars First, I’ll let Jimmy Song explain transaction replay attacks: However what this short video doesn’t cover, is that there are multiple levels of replay protection. I believe a lot of anger and confusion stems from not properly understanding this. So I’ll do my best to explain.