WEBVTT - Automatic transcript; recognition may contain errors. Reviewed for technical wording and speaker labels. Times match the published episode. 00:00:00.530 --> 00:00:02.910 Before the show, a quick word from our sponsor. 00:00:11.780 --> 00:00:14.820 Live from Utrecht, this is the Van Wirdum Sjorsnado. 00:00:15.060 --> 00:00:15.220 Hello. 00:00:15.700 --> 00:00:16.140 Hey Sjors. 00:00:16.360 --> 00:00:16.640 What's up? 00:00:17.530 --> 00:00:21.890 Are you running the BIP 8 true independent client yet? 00:00:22.350 --> 00:00:24.790 Negative. I did not even know there was one. 00:00:25.310 --> 00:00:30.550 Yeah, one has been launched, started. I don't think it's actually a client yet. A 00:00:30.550 --> 00:00:31.430 project has started. 00:00:31.710 --> 00:00:35.330 Okay, a project has started. It's not a binary or a code that you can compile. 00:00:35.590 --> 00:00:41.410 No, not yet. But I did see you were reviewing the BIP 8 code a little bit. 00:00:42.070 --> 00:00:45.990 Yes. I mean, it's… it's a, you know, pull request that has a bunch of changes in 00:00:45.990 --> 00:00:51.250 it. A lot of them are totally not controversial. So I'm just working on it from 00:00:51.250 --> 00:00:51.910 top to bottom. 00:00:52.330 --> 00:00:53.310 Just code review. 00:00:53.650 --> 00:00:57.150 Code review, and I've also started my own pull request where I've taken a couple 00:00:57.150 --> 00:01:01.810 of commits from that just to split it up. Makes everybody's review life… life 00:01:01.810 --> 00:01:06.010 easier. Right. If everybody's talking about LOT is true or LOT is false on a pull 00:01:06.010 --> 00:01:09.610 request, but there's a lot of nitty-gritty stuff that you really don't want to 00:01:09.610 --> 00:01:12.210 screw up just because you're talking about one little thing. 00:01:12.630 --> 00:01:13.210 That's good. 00:01:13.680 --> 00:01:15.940 So that's all good, and we'll see where that ends. 00:01:16.140 --> 00:01:19.660 And I think you were working on something else as well, and that's actually what 00:01:19.660 --> 00:01:20.860 this episode is going to be about. 00:01:21.020 --> 00:01:25.960 By the way, if… if there are independent clients, just be sure to listen to our 00:01:25.960 --> 00:01:29.820 earlier episodes about open source and deterministic builds and all the things 00:01:29.820 --> 00:01:32.280 that can go wrong there, and then do it right. 00:01:32.740 --> 00:01:35.760 Other project, other thing, the other thing you're working on. 00:01:35.920 --> 00:01:37.340 Oh, yeah, hardware wallet stuff. 00:01:37.560 --> 00:01:43.310 Yeah, you're working on not just you, but... I think you're one of the core 00:01:43.310 --> 00:01:47.530 devs working on hardware wallet integration for Bitcoin Core. Is that correct? 00:01:47.810 --> 00:01:52.280 Yeah, that's right. It's me. It's Andrew Chow, instagibbs, as he likes to call 00:01:52.280 --> 00:01:52.820 himself on GitHub. 00:01:53.140 --> 00:01:57.700 Yeah, and you've made some good progress. That was a new merge this week. And 00:01:57.700 --> 00:02:02.230 we're… Basically going to discuss hardware integration in Bitcoin Core in a 00:02:02.230 --> 00:02:04.010 general sense in this episode, I think, right? 00:02:04.270 --> 00:02:04.410 Yep. 00:02:04.610 --> 00:02:07.490 So basically your top specialty, maybe. 00:02:08.050 --> 00:02:09.850 Definitely one of my favorite topics. 00:02:10.510 --> 00:02:14.110 You wanted to refer to some previous episodes where we discussed some of this 00:02:14.110 --> 00:02:14.650 stuff, I think. 00:02:14.910 --> 00:02:19.470 I mean, we talked in the first episode about hardware wallets, sort of the 00:02:19.470 --> 00:02:23.840 security things you need to worry about when it comes to change, etc, so that 00:02:23.840 --> 00:02:28.700 might be a nice refresher. Apologies for the atrocious audio in the first 00:02:28.700 --> 00:02:34.220 episode. There was a literal tornado. I think in episode 7 we 00:02:34.220 --> 00:02:39.400 explained to Peter McCormack but also to other listeners what an xpub is, which 00:02:39.400 --> 00:02:42.580 is quite relevant when it comes to hardware wallets because an xpub represents a 00:02:42.580 --> 00:02:47.580 whole bunch of addresses. And hardware wallets like to communicate that. And then 00:02:47.580 --> 00:02:49.460 there was episode 21, 00:02:50.940 --> 00:02:54.040 which I don't know what it was about, but you should just listen to all of them. 00:02:54.280 --> 00:02:56.800 You put it in a show notes so it has some relevancy. 00:02:57.080 --> 00:02:57.660 That's right. 00:02:58.690 --> 00:03:02.690 Okay, Sjors, where are we with hardware wallet integration for Bitcoin Core? 00:03:02.870 --> 00:03:04.230 Let's just start from the top. 00:03:04.730 --> 00:03:08.800 Yeah, so there was a lot of things that needed to happen, and mainly... that 00:03:08.800 --> 00:03:13.480 which has been done a while ago is to rewrite the entire wallet that Bitcoin Core 00:03:13.480 --> 00:03:18.460 comes with because it was atrocious and that's mostly been done by Andrew Chow. 00:03:18.460 --> 00:03:20.460 I've done a lot of testing and reviewing for that. 00:03:20.460 --> 00:03:23.660 And, what was the problem? What was so bad about it? 00:03:23.660 --> 00:03:29.500 Well it was started by Satoshi and it just had pay to public key addresses in it 00:03:29.500 --> 00:03:33.140 and then pay to public key hash I guess was added and then those other things 00:03:33.140 --> 00:03:38.750 added and then SegWit was added and it just became an unmaintainable mess. So all 00:03:38.750 --> 00:03:44.350 that unmaintainable mess has been put in a box and that box has been abstracted 00:03:44.350 --> 00:03:49.680 in a way that you can create another box that has the same functionality, 00:03:49.680 --> 00:03:53.540 but the implementation can be rewritten from scratch. And so that's kind of what 00:03:53.540 --> 00:03:57.060 we did. We put the existing stuff in a box because we don't want to understand it 00:03:57.060 --> 00:04:02.940 anymore. And we created a new box to replace it with the same form. And that uses 00:04:02.940 --> 00:04:07.300 descriptors. And I guess we'll dedicate some other episode in explaining what 00:04:07.300 --> 00:04:11.520 output descriptors are. But they're kind of a nice, elegant way to describe how 00:04:11.520 --> 00:04:15.460 to derive your addresses from, for example, from the seed. So we say, okay, take 00:04:15.460 --> 00:04:20.570 the seed and then... Take the first account, and then here's an xpub, and then 00:04:20.570 --> 00:04:25.550 take these address derivations, and then I want you to make it a native SegWit 00:04:25.550 --> 00:04:30.310 address. You can express that in one string. And the reason that's nice, and that 00:04:30.310 --> 00:04:35.190 gets just to the hardware wallet part, is because a hardware wallet can then spit 00:04:35.190 --> 00:04:39.190 out that information. So a hardware wallet can tell you, okay, these are the 00:04:39.190 --> 00:04:43.430 addresses I have, and then you just import it. And when your hardware wallet is 00:04:43.430 --> 00:04:46.530 disconnected, you can… you know, exactly which… which addresses the hardware 00:04:46.530 --> 00:04:49.330 wallet has, and you only need to connect when you want to sign something. 00:04:49.830 --> 00:04:54.950 So would the hardware wallet in that case spit out the xpub? Is that why you 00:04:54.950 --> 00:04:56.270 mentioned xpub just now? 00:04:56.670 --> 00:05:02.130 Yeah, well, actually, currently, indeed, it spits out xpubs. Ideally, it would 00:05:02.130 --> 00:05:07.910 spit out these descriptors. So because a hardware wallet might not understand 00:05:07.910 --> 00:05:13.030 what Taproot is, or it might not understand even what SegWit it is. And if it 00:05:13.030 --> 00:05:16.270 just gives you an xpub, well, that xpub doesn't really tell you anything. It's 00:05:16.270 --> 00:05:19.750 just a way to derive addresses, but it doesn't tell you what kind of things it 00:05:19.750 --> 00:05:24.050 can do. So you really want some way for a hardware wallet to tell it what it's 00:05:24.050 --> 00:05:28.770 capable of. But for now, we've avoided having to think about that, using a 00:05:28.770 --> 00:05:30.490 project called HWI. 00:05:30.730 --> 00:05:33.910 Yes, I've seen it a lot, HWI. What does it stand for? 00:05:34.230 --> 00:05:35.730 Hardware Wallet Integration, 00:05:36.230 --> 00:05:36.510 Nice. 00:05:36.790 --> 00:05:38.030 Or interface, I guess… 00:05:38.170 --> 00:05:39.050 Or which one is it, Sjors? 00:05:39.490 --> 00:05:41.830 I don't care. I think it's interface. 00:05:42.130 --> 00:05:42.290 Okay. 00:05:42.830 --> 00:05:44.530 So that is a Python library. 00:05:45.970 --> 00:05:50.890 And again, mostly by Andrew Chow. What he did is, because all these hardware 00:05:50.890 --> 00:05:54.650 wallets, like the Trezor and the Ledger and the KeepKey and the COLDCARD, etc., 00:05:54.650 --> 00:05:57.970 they all have their own little Python libraries that you can find on GitHub 00:05:57.970 --> 00:06:01.860 because it's all open source. But they're all different. They all have different 00:06:01.860 --> 00:06:05.700 ways to display an address. They have different ways to get an xpub. They have 00:06:05.700 --> 00:06:11.240 different ways to sign a transaction. So what he did is he combined all these 00:06:11.240 --> 00:06:15.310 drivers. Stripped all the shit coins out of them because some of them would do 00:06:15.310 --> 00:06:17.250 Ethereum things and we don't want Ethereum code. 00:06:17.750 --> 00:06:18.470 I don't. 00:06:18.630 --> 00:06:23.930 And then basically put that all together in one little library and made it 00:06:23.930 --> 00:06:29.770 consistent. So as far as the user is concerned, you tell HWI Enumerate and it 00:06:29.770 --> 00:06:32.550 will give you the list of all the connected hardware wallets using all these 00:06:32.550 --> 00:06:38.250 different drivers to find them. And if you say, get descriptors, then it will 00:06:38.250 --> 00:06:43.190 give you a list of descriptors that describe exactly what keys, what addresses 00:06:43.190 --> 00:06:46.790 the hardware wallet has. And it does all the magic of fetching xpubs using 00:06:46.790 --> 00:06:48.210 whatever method is necessary. 00:06:48.450 --> 00:06:53.750 So could I describe HWI as sort of like a meta protocol 00:06:53.750 --> 00:06:59.570 that communicates with all of the different hardware wallet protocols, so to say? 00:07:00.210 --> 00:07:06.160 Yeah, I guess. Another way to say it is that HWI is a tool. But 00:07:06.160 --> 00:07:10.420 it has a way of communicating. You have a way of giving it commands, and that is 00:07:10.420 --> 00:07:15.460 a protocol, essentially. So somebody else could make a tool that behaves the same 00:07:15.460 --> 00:07:21.150 as HWI, but is just for their own hardware wallet. So a hardware wallet 00:07:21.150 --> 00:07:26.170 manufacturer doesn't have to let people use HWI. They could make their own driver 00:07:26.170 --> 00:07:30.530 that just behaves the same way as HWI. And then Bitcoin Core, as we'll discuss 00:07:30.530 --> 00:07:32.030 next, will know how to talk to it. 00:07:32.510 --> 00:07:37.750 Right. And if someone brings a new hardware wallet to the market, which does its 00:07:37.750 --> 00:07:43.130 own thing again, then HWI will be updated potentially to be able to communicate 00:07:43.130 --> 00:07:43.850 with that as well? 00:07:44.070 --> 00:07:48.670 Yeah. So depending on the enthusiasm of the maintainers of HWI, they might... Go 00:07:48.670 --> 00:07:54.430 out and find that driver and include it. If the enthusiasm is slightly 00:07:54.430 --> 00:07:59.890 less, then the manufacturer or a fan, a user, can go to, you know, can go to HWI, 00:07:59.930 --> 00:08:02.730 make a pull request and say, hey, here's the support for this new hardware 00:08:02.730 --> 00:08:07.870 wallet. And then recently there were some guidelines merged for that. So the 00:08:07.870 --> 00:08:11.690 hardware wallet has to be open source. At least the firmware that runs on it has 00:08:11.690 --> 00:08:15.790 to be open source, with the only exception being if there's a secure element in 00:08:15.790 --> 00:08:17.670 it that's under NDA, that's okay. 00:08:18.920 --> 00:08:24.140 And it has to be sort of maintainable, the software. But then, yeah, anybody can 00:08:24.140 --> 00:08:29.910 just make support, add support for any other hardware wallet to HWI. 00:08:30.190 --> 00:08:33.570 But again, it's not necessary. You could also, the hardware manufacturer could 00:08:33.570 --> 00:08:38.600 also make their own software that just speaks the same language as HWI. 00:08:39.670 --> 00:08:44.270 Right. And HWI was already merged into Bitcoin Core? 00:08:44.470 --> 00:08:49.350 So HWI is a separate program. That's in the Bitcoin… not in the Bitcoin Core 00:08:49.350 --> 00:08:53.570 repository, but there is a GitHub, there's a GitHub organization called Bitcoin 00:08:53.570 --> 00:08:59.330 Core, which has a bunch of repositories. And that includes HWI. So it's 00:08:59.330 --> 00:09:04.030 separate from Bitcoin Core because it's all this Python stuff and USB drivers. So 00:09:04.030 --> 00:09:08.130 I guess we don't want to put that in the Bitcoin source code because that's too 00:09:08.130 --> 00:09:11.590 scary with all the dependencies. But it is maintained by Bitcoin Core people. So 00:09:11.590 --> 00:09:16.910 it's a trust slightly less or... I don't know how to put it. 00:09:17.550 --> 00:09:23.550 Okay, so HWI is... A separate program, essentially. And it needs 00:09:23.550 --> 00:09:25.990 to be installed separately if you want to use it? 00:09:26.230 --> 00:09:29.670 Exactly. You can download it separately, install it separately, or just put it somewhere. 00:09:30.290 --> 00:09:34.570 Right. It's not in the Bitcoin Core client that I'm running at home? 00:09:34.730 --> 00:09:35.090 No. 00:09:35.330 --> 00:09:35.550 Got it. 00:09:35.750 --> 00:09:38.490 Because that would, you know, in order for that to happen, first of all, it will 00:09:38.490 --> 00:09:42.750 probably have to be written in C++ or in Rust or something like that. And all the 00:09:42.750 --> 00:09:46.930 USB drivers would have to be inspected with a tooth comb. And that'll take 00:09:46.930 --> 00:09:51.850 forever. So yeah, it's something you install separately. And there is some risk, 00:09:51.970 --> 00:09:53.510 obviously, with just running that software. 00:09:54.150 --> 00:09:57.330 Right. But this is not new, is it? 00:09:57.950 --> 00:10:00.590 That's right. HWI has been around for at least a year. 00:10:00.950 --> 00:10:05.570 Right. So what was merged this week? Or am I getting ahead of the podcast? 00:10:05.610 --> 00:10:06.650 That's exactly right. 00:10:06.710 --> 00:10:08.510 Okay, so what was merged last week? 00:10:08.550 --> 00:10:13.630 So before last week, if you wanted to use HWI with Bitcoin Core, you can do that. 00:10:13.890 --> 00:10:18.280 But you have to execute a bunch of commands manually. So for example, if you 00:10:18.280 --> 00:10:21.800 wanted to sign a transaction, you would tell Bitcoin Core, okay, I'd like to 00:10:21.800 --> 00:10:24.880 create a PSBT. So we explained PSBT in an earlier episode. 00:10:25.060 --> 00:10:26.920 Yeah, partially signed Bitcoin transactions. 00:10:27.140 --> 00:10:30.240 Exactly. So you tell Bitcoin Core, okay, give me a PSBT, a partially signed 00:10:30.240 --> 00:10:34.760 transaction. In this case, actually an unsigned transaction probably to the 00:10:34.760 --> 00:10:39.580 destination. And then you would copy paste the result and you'd say, okay, HWI, 00:10:39.760 --> 00:10:45.170 please sign this thing. And then HWI would do its thing. And then you get a 00:10:45.170 --> 00:10:48.030 result and you copy-paste that back into Bitcoin Core and say, Bitcoin Core, 00:10:48.170 --> 00:10:50.130 please process this thing and send this thing. 00:10:50.370 --> 00:10:54.630 Ah, right. So you're running both programs, the Bitcoin Core program and the HWI 00:10:54.630 --> 00:11:00.310 program, and then you're manually basically sending data from copy-pasting data 00:11:00.310 --> 00:11:01.230 from one to the other… 00:11:01.430 --> 00:11:02.750 And [unclear]… 00:11:02.750 --> 00:11:06.890 Using your hardware wallet on HWI, getting some signature and then copy-pasting 00:11:06.890 --> 00:11:08.690 it to Bitcoin Core, and that's how it would work. 00:11:08.830 --> 00:11:09.090 Exactly. 00:11:09.170 --> 00:11:12.100 And you're doing this all in the command line, I assume? 00:11:11.940 --> 00:11:17.180 Yes, that's right. And there was already some help with that because HWI also 00:11:17.180 --> 00:11:21.280 comes with a little graphical program where you can actually click buttons to 00:11:21.280 --> 00:11:24.000 make it do these things. But you'd still be copy-pasting back and forth at 00:11:24.000 --> 00:11:24.460 Bitcoin Core. 00:11:24.660 --> 00:11:25.400 I love buttons. 00:11:26.020 --> 00:11:31.920 Yeah, so do I. So what is new now is that Bitcoin Core now knows how to 00:11:31.920 --> 00:11:36.440 communicate with HWI. Still from the command line, but it still gets easier. 00:11:36.600 --> 00:11:40.660 Because now when you want to send coins, you just tell Bitcoin Core, send, and 00:11:40.660 --> 00:11:45.740 then the destination, and the amount. And it will know that it needs the hardware 00:11:45.740 --> 00:11:51.100 wallet. So it will say, hello, HWI, please do these things. And it will wait for 00:11:51.100 --> 00:11:54.880 the result and it will process the result and it will send the transaction. So 00:11:54.880 --> 00:11:59.700 you go from like four back and forth with copy pasting to just send and it works. 00:11:59.940 --> 00:12:00.940 No more copy pasting. 00:12:01.080 --> 00:12:05.080 That's right. So all you need to do is tell Bitcoin Core where HWI lives. So 00:12:05.080 --> 00:12:09.220 where on your computer you installed it. And then it will just call it for you. 00:12:09.550 --> 00:12:14.030 Right, so if you know how to work the command line, this is a pretty big 00:12:14.030 --> 00:12:14.850 improvement, I guess. 00:12:15.130 --> 00:12:19.710 This is significantly less tedious, yeah. I have used both the approaches, like 00:12:19.710 --> 00:12:22.550 with the manual back and forth, and with this, it's much easier. 00:12:22.690 --> 00:12:24.690 But you do still need to use the command line. 00:12:25.490 --> 00:12:30.750 Yeah, or in Bitcoin Core, you have this window, the debug console, which is 00:12:30.750 --> 00:12:32.170 essentially a little command line. 00:12:32.290 --> 00:12:33.550 Right, right. 00:12:34.080 --> 00:12:37.620 So I cannot do it in the user interface, but you can actually, yeah, you can open 00:12:37.620 --> 00:12:40.760 this window console and then you can just type send and it'll work. 00:12:40.960 --> 00:12:46.400 Right. So this was merged into Bitcoin Core, which will be released in, I guess 00:12:46.400 --> 00:12:48.440 it will probably be Bitcoin Core 22. 00:12:49.000 --> 00:12:51.820 Yeah, Bitcoin Core 22 should be out in, I don't know, fall. 00:12:52.880 --> 00:12:57.080 Might it also come into a minor release? I guess that might depend on Taproot 00:12:57.080 --> 00:12:57.900 activation stuff. 00:12:58.140 --> 00:13:00.220 This is not the kind of stuff that would be backported. 00:13:00.720 --> 00:13:04.500 No? So it's definitely going to be a major release. Is that what you're saying? Yeah. 00:13:04.840 --> 00:13:09.680 Because for things to backport, it has to be simple enough, or like a really 00:13:09.680 --> 00:13:13.100 critical bug fix. But usually the only things that are backported are bug fixes 00:13:13.100 --> 00:13:16.880 and soft forks, but not entire new features. 00:13:17.660 --> 00:13:21.540 Got it. Okay, so this will be in the upcoming Bitcoin Core 22 release. 00:13:21.740 --> 00:13:24.000 Yeah, or if you compile the master branch yourself. 00:13:24.860 --> 00:13:30.160 Sure. The step after that, I would assume, would be GUI support? 00:13:30.460 --> 00:13:34.560 GUI support? That's right. Yeah, because still, you know, having to type commands 00:13:34.560 --> 00:13:38.640 is kind of annoying. So I have a pull request open that builds on top of this, 00:13:38.680 --> 00:13:43.180 and it adds a couple of things. It adds something to the settings screen. So 00:13:43.180 --> 00:13:46.980 there is a settings screen in Bitcoin Core, and there you tell it where HWI 00:13:46.980 --> 00:13:50.520 lives. So you don't have to give that to the command line. You just copy-paste 00:13:50.520 --> 00:13:51.480 that file directory. 00:13:52.960 --> 00:13:57.810 And then… When you go to the menu to create a wallet, if you have 00:13:57.810 --> 00:14:03.550 this HWI path correctly and you have a hardware wallet inside your computer 00:14:03.550 --> 00:14:08.710 and it's unlocked, if you create a new wallet, it'll detect it. So it'll say, oh, 00:14:08.950 --> 00:14:14.890 would you like to use this Ledger X or whatever? And then you click next. And 00:14:14.890 --> 00:14:19.250 it will automatically pull the keys from the device, and your wallet will just 00:14:19.250 --> 00:14:21.230 look like any other wallet, but if you click on your address… 00:14:21.230 --> 00:14:23.030 It will pull the public keys, to be clear, right? 00:14:23.130 --> 00:14:27.730 Correct, yeah, public keys. It pulls the public keys from the device, and your 00:14:27.730 --> 00:14:30.870 wallet will work just as any other wallet. You can click on receive address, 00:14:30.870 --> 00:14:34.210 you'll see an address. And then the other feature is that if you click on a 00:14:34.210 --> 00:14:38.530 receive address, so in Bitcoin Core you click on get me a new address, then it 00:14:38.530 --> 00:14:42.510 kind of makes a little mini address book. And you can right click on that, I 00:14:42.510 --> 00:14:46.780 believe, and then click on verify. That's a new button. And the verify button, 00:14:47.240 --> 00:14:50.800 again, if the device is plugged in, will [unclear] show the address on the 00:14:50.800 --> 00:14:51.300 hardware wallet. 00:14:51.420 --> 00:14:51.840 Right, yep. 00:14:51.940 --> 00:14:52.600 So you can check that it's real. 00:14:52.840 --> 00:14:53.020 Yep. 00:14:53.440 --> 00:14:58.720 And then the… the third thing that's added is you can now just send Bitcoin as 00:14:58.720 --> 00:15:01.920 you would in Bitcoin Core. Just click on send and type the destinations 00:15:01.920 --> 00:15:07.800 [unclear]. And when you hit send, if the device is plugged in, it'll show up on 00:15:07.800 --> 00:15:13.370 the device and you click on approve. And it just sends it. Now, the downside is 00:15:13.370 --> 00:15:18.010 that if anything does not go exactly right as I just described it, it will 00:15:18.010 --> 00:15:18.570 probably crash. 00:15:18.770 --> 00:15:19.130 Right. 00:15:19.230 --> 00:15:20.190 So it's still work in progress. 00:15:20.470 --> 00:15:25.210 Would it work with all of Bitcoin Core's current features? So that would be, for 00:15:25.210 --> 00:15:30.090 example, be RBF, I guess, and sent to many or whatever it's called, batching, 00:15:30.310 --> 00:15:31.230 these kinds of things. 00:15:31.430 --> 00:15:35.590 Well, if in the graphical interface you can send a transaction, you can send it 00:15:35.590 --> 00:15:41.020 to like 10 different recipients if you want to, that'll work. I believe RBF... I 00:15:41.020 --> 00:15:45.660 have not implemented because internally that does a few other things. I don't 00:15:45.660 --> 00:15:49.160 know, you can try. But it will be trivial to add that as a follow-up. 00:15:49.200 --> 00:15:49.600 Right. 00:15:49.540 --> 00:15:52.760 But I try to keep these pull requests as minimum as possible. So these are like 00:15:52.760 --> 00:15:55.950 three features that I think are really at least good enough. 00:15:56.630 --> 00:16:01.310 Sorry, are these things possible now? Are we just talking about GUI? 00:16:01.750 --> 00:16:05.290 Yeah, the GUI pull request. Right now you can do all these things with the 00:16:05.290 --> 00:16:10.050 command line, right, but they'll work in the GUI. Which is very nice because, 00:16:10.350 --> 00:16:14.710 especially coin selection. So in the command line, typing send an address and an 00:16:14.710 --> 00:16:15.850 amount, that's not too bad. 00:16:16.270 --> 00:16:18.550 Yeah, other good example, right? Coin selection. 00:16:18.790 --> 00:16:23.130 But the coin selection is only practical in the GUI. So you can actually decide 00:16:23.130 --> 00:16:26.970 which coins to spend. And having coin selection with hardware wallets is very nice. 00:16:27.230 --> 00:16:28.330 Yeah, I agree. 00:16:29.720 --> 00:16:34.860 It does work, but it only works if it doesn't crash. So that just needs more 00:16:34.860 --> 00:16:39.440 review and requires me to fix things and maybe make it asynchronous so the screen 00:16:39.440 --> 00:16:41.460 doesn't block while the hardware wallet is doing something. 00:16:41.960 --> 00:16:46.120 Yeah, this will probably not be ready before Bitcoin Core 22. I don't know. 00:16:46.260 --> 00:16:46.740 I'm bullish. 00:16:47.060 --> 00:16:48.000 You think it might be? 00:16:49.120 --> 00:16:53.340 It depends on the review because I have a couple of things that I want to improve 00:16:53.340 --> 00:16:56.980 about it, but I tend to get more motivated when people start screaming at me in 00:16:56.980 --> 00:16:57.420 the reviews. 00:16:58.780 --> 00:17:02.620 I can scream at you in the reviews. I won't say anything useful, but I can scream at you. 00:17:02.680 --> 00:17:05.720 Well, you do have to actually test it, right? Don't just come in from Twitter and 00:17:05.720 --> 00:17:08.760 comment on it. But if you actually run the code and something goes wrong, then 00:17:08.760 --> 00:17:10.620 I'll try to help or fix the bug. 00:17:11.320 --> 00:17:16.580 I'll consider that as well. I could consider that. What about multisig? 00:17:17.530 --> 00:17:19.430 Using, that's like one of the arguably safest… 00:17:19.430 --> 00:17:22.410 Yeah, so everything I've described so far is single sig. 00:17:22.950 --> 00:17:27.210 Yeah, so for example, if you'd want to use three hardware wallets and then two 00:17:27.210 --> 00:17:29.830 out of three stuff like that. 00:17:30.470 --> 00:17:34.090 Well, eventually I'd like to see something similar to how Electrum, you know, 00:17:34.170 --> 00:17:35.450 just lets you make a pie chart. 00:17:35.970 --> 00:17:36.670 Yes, exactly. 00:17:37.010 --> 00:17:40.830 None of that is there yet, not even in the command line. It is possible. I think 00:17:40.830 --> 00:17:44.670 I once made an experimental pull request that did do multi-sig at least from the 00:17:44.670 --> 00:17:49.030 command line. But there's a lot of moving parts. So I'd like to get all the 00:17:49.030 --> 00:17:53.050 single-sig stuff merged. Then we'll move on to multi-sig. So Bitcoin Core 00:17:53.050 --> 00:17:58.850 multi-sig with hardware wallets will be a while. That said, well, there's another 00:17:58.850 --> 00:17:59.390 way to do it. 00:18:00.010 --> 00:18:02.130 There's another way. That's great. Let's hear it. 00:18:02.250 --> 00:18:04.630 This project is called Specter. 00:18:05.370 --> 00:18:06.370 Specter wallets, yes. 00:18:06.750 --> 00:18:10.650 Which is very cool. Specter is also a hardware wallet, but in this case, what 00:18:10.650 --> 00:18:15.090 we're talking about is the Specter desktop software. Another Python project. 00:18:15.250 --> 00:18:16.930 There's a device, a Specter device. 00:18:17.130 --> 00:18:20.990 Yeah, it's very cool. I should have brought it with me. But it's a do-it-yourself 00:18:20.990 --> 00:18:25.190 hardware wallet. So you can actually order the components from any manufacturer 00:18:25.190 --> 00:18:31.190 that sort of makes these Arduino-like or smartphone-like things. And you take 00:18:31.190 --> 00:18:36.660 a QR scanner and you solder it on it. This is by by Stepan Snigirev. 00:18:37.270 --> 00:18:40.830 He's been working on that. He's also been working, I believe, on support for 00:18:40.830 --> 00:18:45.590 actual secure elements so that you can buy your own secure element from like a 00:18:45.590 --> 00:18:49.790 manufacturer that makes a lot of these general purpose secure elements. So they 00:18:49.790 --> 00:18:52.750 might not even know that you're using it for Bitcoin purposes, which is very nice 00:18:52.750 --> 00:18:53.490 supply chain wise. 00:18:53.690 --> 00:18:53.830 Right. 00:18:54.110 --> 00:18:58.890 And you don't have to trust them. Yeah, it's very cool. Basically, you can do a 00:18:58.890 --> 00:18:59.570 lot of stuff with it. 00:18:59.830 --> 00:19:03.670 That's the device. We were actually going to talk about the wallet, I guess, the software. 00:19:03.520 --> 00:19:07.070 Because… because I guess in order for them to develop that device, they wanted to 00:19:07.070 --> 00:19:11.030 use that inside a multisig setup. And so they… they spent a lot of time building 00:19:11.030 --> 00:19:16.800 a multisig system. And that is called the Specter Desktop. What it does is, 00:19:17.060 --> 00:19:21.200 again, it's a program you download and it opens on your computer. And then it 00:19:21.200 --> 00:19:26.250 says, hey, where's Bitcoin Core? Or hopefully it finds it. And then if it finds 00:19:26.250 --> 00:19:29.890 Bitcoin Core, it says, okay, well, Bitcoin Core is synced. It's got all the 00:19:29.890 --> 00:19:33.930 blocks. Do you have any devices you'd like to configure? And then you say, okay, 00:19:34.050 --> 00:19:39.270 yeah, I have a Ledger wallet and I have a Trezor wallet and whatever. You add 00:19:39.270 --> 00:19:43.050 those devices one by one by just plugging it in. And under the hood, that uses 00:19:43.050 --> 00:19:43.730 HWI. 00:19:44.890 --> 00:19:47.010 Specter uses HWI as well, right? 00:19:47.150 --> 00:19:50.990 Yeah, it just comes bundled with it. So it knows how to detect them, it knows how to add them. 00:19:51.050 --> 00:19:52.890 So you need to install HWI as well? 00:19:53.030 --> 00:19:54.750 No, I think Specter just has… 00:19:54.750 --> 00:19:56.010 Oh, it includes it. 00:19:56.170 --> 00:19:56.330 Yeah. 00:19:56.450 --> 00:19:56.870 Right, got it. 00:19:56.910 --> 00:19:59.490 Yeah, so that's the trade-off, right? So in Bitcoin Core, we don't just want to 00:19:59.490 --> 00:20:02.550 add HWI, but in Specter, they do. 00:20:03.320 --> 00:20:03.740 Got it. 00:20:04.510 --> 00:20:09.590 And then basically you add devices and then you say, okay, I'd like to configure 00:20:09.590 --> 00:20:14.120 a wallet. And the terminology is a bit confusing. That's why I use the word 00:20:14.060 --> 00:20:17.160 device… device because the device is also a wallet. 00:20:17.120 --> 00:20:17.460 But yep. 00:20:17.580 --> 00:20:20.880 We create a wallet and you say, okay, I want to combine the Trezor and the Ledger 00:20:20.880 --> 00:20:26.770 and I want a two of two sure, or one of two. And then it says, okay, 00:20:26.830 --> 00:20:31.010 I'm going to create a wallet now. And it creates that wallet in Bitcoin Core. So 00:20:31.010 --> 00:20:35.010 that means that Specter does not have to maintain all the code necessary to 00:20:35.010 --> 00:20:38.590 create a whole wallet from scratch, because that's a lot of work. It lets Bitcoin 00:20:38.590 --> 00:20:42.700 Core do that. It also means it can let Bitcoin Core do all the coin selection magic. 00:20:43.300 --> 00:20:46.280 And this uses the GUI of Bitcoin Core? 00:20:46.520 --> 00:20:50.440 No, it creates its own GUI, which is basically just a little web server on your 00:20:50.440 --> 00:20:54.180 own computer, kind of like how a modem looks if you log in, log into the admin panel. 00:20:55.230 --> 00:21:00.890 Right. So it uses Bitcoin Core as a backend, but you're actually looking 00:21:00.890 --> 00:21:05.090 at Specter, which also includes HWI. 00:21:05.410 --> 00:21:08.990 Yeah, that's right. And I guess one scenario where this might be nice is if you 00:21:08.990 --> 00:21:13.810 run Bitcoin Core, not on your computer, but on a Raspberry Pi somewhere, which 00:21:13.810 --> 00:21:16.510 might not have a screen, or at least you don't want to use the screen. And you 00:21:16.510 --> 00:21:20.570 could imagine remote connecting to your Raspberry Pi with Bitcoin Core running on 00:21:20.570 --> 00:21:24.630 it. And you're not worried because your keys are not on Bitcoin Core. It's just 00:21:24.630 --> 00:21:28.870 the read-only stuff is on Bitcoin Core. So your Raspberry Pi in your living room 00:21:28.870 --> 00:21:34.730 with no security is not really a threat, but it is a full node. And yeah, 00:21:34.850 --> 00:21:36.250 so you can use it that way. 00:21:36.630 --> 00:21:37.950 Yeah, so that's one way. 00:21:37.950 --> 00:21:40.890 It looks pretty slick. It's very easy to use in my experience once you get it running. 00:21:41.110 --> 00:21:46.010 So that's one way to use a hardware wallet in combination with Bitcoin Core 00:21:46.010 --> 00:21:47.190 already, including... 00:21:48.760 --> 00:21:50.520 Including multi-sig solutions. 00:21:51.020 --> 00:21:55.220 Yeah, especially the latter. I guess, you know, soon TM, you'll be able to use 00:21:55.220 --> 00:21:59.100 Bitcoin Core with single-sig, and then I would say the fewer moving parts you 00:21:59.100 --> 00:22:02.640 have, the better. So nothing against Specter, but if you don't need it, then 00:22:02.640 --> 00:22:03.840 don't run additional code. 00:22:04.060 --> 00:22:04.220 Yeah. 00:22:04.680 --> 00:22:08.300 But for multi-sig, it's great. And to get that kind of UI, especially in Bitcoin 00:22:08.300 --> 00:22:10.360 Core, that's going to take a while. 00:22:10.940 --> 00:22:14.820 Yeah, there are a couple of other solutions like this. You already mentioned 00:22:14.820 --> 00:22:19.350 Electrum. Which you could, of course, also run in combination with your personal 00:22:19.350 --> 00:22:22.870 Electrum server, in which case you're also using full node security. 00:22:23.190 --> 00:22:28.570 Yeah, although I'd have to see, I don't know if Electrum personal server also has 00:22:28.570 --> 00:22:31.910 support for multisig, but in theory that could be added. 00:22:33.060 --> 00:22:38.120 Yeah, there's something called a Lily wallet. I don't know if that uses full node 00:22:38.120 --> 00:22:41.160 security. I've never used it. It looks very slick. I've seen that. 00:22:41.340 --> 00:22:41.480 Okay. 00:22:41.640 --> 00:22:47.140 But that also allows for hardware wallets, multi-setup stuff. I think, but I 00:22:47.140 --> 00:22:51.360 could be wrong. I think that's SPV light-client type of wallet though. 00:22:51.440 --> 00:22:52.480 I'm not, I don't know. 00:22:52.640 --> 00:22:54.580 I think there's also one called Caravan. 00:22:54.860 --> 00:22:56.180 Caravan, yep. I've heard of that. 00:22:56.460 --> 00:23:00.580 I don't know much about Caravan. I know it does something similar. 00:23:01.130 --> 00:23:06.130 Yeah, that's what I heard too. And then there is, I guess, Casa. I don't know how 00:23:06.130 --> 00:23:10.670 they do it. So yeah, there's all sorts of ways. I… I imagine in the future this 00:23:10.670 --> 00:23:13.120 is going to get better and better. Right, so now we have… 00:23:12.350 --> 00:23:14.950 Well, it's getting better already, clearly. 00:23:15.210 --> 00:23:19.030 Well, we talked about very simple multisig setups, but imagine a scenario where 00:23:19.030 --> 00:23:23.450 we have not just Taproot. Yeah, we have Taproot, and then we have Miniscript, 00:23:23.630 --> 00:23:26.970 which we talked about in an earlier episode, which allows you to make far more 00:23:26.970 --> 00:23:32.710 complicated setups. So now you can imagine instead of a two or three setting 00:23:32.710 --> 00:23:38.540 where you have two hardware wallets, one you keep in a vault somewhere, one you 00:23:38.540 --> 00:23:44.490 keep wherever you are. And then the third key, quote unquote, is not actually a 00:23:44.490 --> 00:23:48.170 single key. It's not a single device. It is some sort of bank, some sort of bank 00:23:48.170 --> 00:23:53.920 that helps you. And they internally use some extremely complicated setup, which 00:23:53.920 --> 00:23:56.360 you don't have to understand. From your point of view, it just looks like one 00:23:56.360 --> 00:24:01.160 signature. In reality, it's very complicated. And it can all be communicated 00:24:01.160 --> 00:24:04.820 through Miniscript. And then you do something like Specter. So you and your site 00:24:04.820 --> 00:24:08.260 can make sure everything works. And only when you need the bank, then you need to 00:24:08.260 --> 00:24:12.080 ask them for a signature. Sure. But other than that, it all just works from your 00:24:12.080 --> 00:24:15.900