Looking for a lightweight Bitcoin Core fork

Is there anyone out there working on a slimmed-down version of Bitcoin Core that just focuses on legacy address support, segwit, and coin control? I’m not really interested in Taproot or any other features that just complicate things. Honestly, I’d be fine with just legacy since I don’t do many transactions, and anything beyond that feels like a security tradeoff to me. All those extras just seem like unnecessary clutter. One feature I do find handy is being able to generate a PSBT file to avoid messing up the command line when creating a raw transaction and sending it to an online node for broadcasting. But I really want to strip away anything that adds to the complexity with stuff I won’t ever use. All I need is the ability to send and receive from A to B. I feel like if we could just have the Bitcoin Core from a decade ago, with essential bugs fixed, that would be perfect.

The only fork of Bitcoin Core software i know is Bitcoin Knots. But it's not lightweight since it also download whole blockchain and have additional features. If you just need lightweight wallet either as hot or cold wallet, Electrum mostly match your requirement since it support PSBT, while until now it doesn't support creating Taproot address.

What is it you're worried about, specifically? If security is a concern, you'd probably gain more by setting up cold storage or getting a hardware wallet. Having the logic for Taproot support as part of your wallet's code should not affect your ability to send regular transactions in any way, let alone open up any new security holes (with using a hot wallet in itself being by far the largest security concern).

Considering how Taproot and other things are part of the Bitcoin protocol, any fork that doesn't have it is not exactly Bitcoin anymore. As for security, there is no trade off whatsoever and security of Bitcoin has not changed nor did the implementation of called Bitcoin Core. If it had, the entire Bitcoin as a network and system would be insecure not just your client alone. As for the "code clutter", the code has actually gotten cleaner and more categorized and also a lot more improved and optimized over the years.

How do you intend to send from A to B if B is giving you a taproot address? Outside of my signature campaign payments here, and brutally honest when I am too lazy to generate a new address and reuse an old one I have handy, by default my wallet only generates taproot. And keep in mind taproot allows the use of Schnorr Signatures, which offers better security. But anyway, there is nothing that really does what you want. You could probably put together something and compile it yourself but that's about it. -Dave

Since you've written that no one can change your mind: Use Bitcoin Core v0.20.2 which doesn't include TapRoot implementations (including test networks), but its last patch was 3 years ago so use it at your own risk. That client wont relay transactions that has TapRoot inputs but will still accept the blockchain like a normal Bitcoin node would. And its GUI/RPC supports PSBT, but quite outdated.

Yeah, probably a good idea not to use it. Core prior to v0.22.0 has several DoS vulnerabilities that aren't fixed. Unfortunately, I believe Core is one of the more optimized and maintained wallets out there. If you are using anything other than that, there is a potential that it isn't as optimized or with bugs[1]. [1] https://blog.lopp.net/2023-bitcoin-node-performance-tests/

But the fork could be based on older Bitcoin Core version, which doesn't contain Taproot support. It's also worth to mention since that version, there are few updates to PSBT feature[2-3]. [1] https://github.com/bitcoinj/bitcoinj [2] https://bitcoincore.org/en/releases/0.21.0/ [3] https://bitcoincore.org/en/releases/25.0/

Those are part of the Bitcoin Core's code, your node doesn't need to have any of that if you don't want to and it's still Bitcoin. I don't need anything that isn't moving money from A to B in a legacy address, any other "features" added after that just add complexity and potential exploits, as well as nonsense usages of block space like ordinals and co. Anything that isn't for moving money from A to B is just cluttering both code and block space but "Bitcoin developers" like to "develop" this thing as if it was a Google app apparently. Let's just hope no fatal bug is added along the way as such experimental features are added on the most used node software. I don't trust hardware wallets, I use a 2 laptop setup with 2 Bitcoin Core instances, one used as cold wallet and another as hot wallet with watch only addresses. If most of the network uses code that eventually adds some sort of exploit or bug with all that experimental creativity being added you will care as you see the price crash irrespective of how you are holding the coins.

If you can trust Bitcoin Core, i don't understand why you don't trust hardware wallet. There are some hardware wallet which is fully open source, where you can even build one by yourself. Good thing Bitcoin Core isn't the only Bitcoin full node software out there. Anyway, if you're looking for something that less "bloated" than Bitcoin Core, you should check gocoin[1]. It's solo developed by one person for more than a decade and have less code lines. [1] https://github.com/piotrnar/gocoin

I can think of a few reasons. The most important one: it's a black box. I have to trust the manufacturer to do what they say they do, and sometimes they turn 180 degrees. Who's really able to do that?

Fair point. Although IIRC Ledger was never fully open source, partially due to closed-source secure element. Someone with some electronics and computer skill. I've seen few people build their own Trezor and Blockstream Jade.

Aren't the components still black boxes? I've seen more discussion about potential bias in dice rolls than about potential problems with hardware wallets. The fact that it's always recommended to buy directly from the manufacturer makes me think there's a lot of trust involved.

I don't engage much on electronic field. But on some cases, you can choose various electronic board/module, where i expect few of them are fully open source. For example, Blockstream recommend 8 different board/module if you want to build your own Jade[1]. At minimum, i do not expect backdoor designed to steal Bitcoin on such general electronic board/module. [1] https://github.com/Blockstream/Jade/tree/master/diy

That's quite an assumption. I'd prefer a much more generic air-gapped laptop with a generic Linux distribution and Bitcoin Core (or Electrum). I don't want Ordinals (spam) either, but as long as it's using Bitcoin blocks, your node will have to verify them. Let's assume you switch to much less popular and much less tested software that offers less features than Bitcoin Core. What makes you think that software is less likely to have bugs?

Those are part of the Bitcoin consensus rules not just core's code. But it's true that you don't need to verify everything you be using Bitcoin. But you also don't need to download the entire blockchain if you aren't going to verify everything (it won't be a "full node" if you don't), maybe you should look into using a SPV client. Well whether you run a full node that can verify new features such as Taproot or run an old client that doesn't verify everything won't change the fact that the abusers will continue spamming. Taproot and the Schnorr signatures aren't some "experimental" feature and it wasn't added to this software. It is a solid algorithm that is added to the Bitcoin protocol.

I wouldn't trust Laptop because god knows whether there are backdoors in hardware or not. Hardware wallet looks to be easier work compared to PC/Laptop components. To be honest, I have said it many times that if you don't hold thousands of Bitcoins, you are most likely safe. What's going happen if you hold 1 Bitcoin on Coldcard wallet at home? Anyone is going to hack it? Really? To be honest again most of us have to trust developers. If you can't read a code and aren't a very good software developer or engineer or whatever it is, then you can't be sure that you are safe with any open-source software, you depend on someone else's opinion.

That's why you use a cold wallet setup, and check the transaction before signing. True. A hardware wallet is usually recommended to Newbies instead of creating your own airgapped cold wallet. You're talking about targeted attacks. In reality, it's mostly automated malware that steals any amount it can.

I already use cold storage on a laptop. My question is, I wanted to have a Bitcoin Core feature that does the bare minimum. Like Bitcoin Core would be Ubuntu, what I would like is Xubuntu, this way you still contribute to the network, keep a full copy of the blockchain, and you are able to use the nice Coin Control feature, keep watch only features to check your funds and broadcast transaction, but you would get rid of anything else that I consider to be too fancy. In addition, you don't want to use a hardware wallet at all, this has always been my philosophy, for an obvious reason. When you own a hardware wallet, you are a target. When a thief finds it, he has an insane incentive to try to bruteforce it, exploit it and so on, compared to some old laptop, in principle, it's irrelevant. Here's more: https://blog.merklescience.com/general/dark-skippy-a-new-threat-to-hardware-wallets As exploits and hacks become better, you don't want to give anyone the chance to try that on your shinny device. Just use a boring laptop in my opinion. If you want to transact on the move, use a phone or some other smaller device where you only carry a small amount.

Such thing doesn't exist. Bitcoin Knots is the only alive fork of Bitcoin Core, which actually has more feature. If the attacker could install malicious firmware on your hardware, it's likely the attacker also have full control over your device (such as computer) anyway.