Calle on Bitchat: Messaging When The Internet is Shut Down

**Calle** (0:00)
BitChat came in a time where phones just got really good at using Bluetooth low energy. You know, it also came together with a year of political unrest around the world. All of that is almost like a perfect storm situation where there is demand for alternative communication media in general. And it's a natural desire of people to defend against injustice and protect themselves and protect their friends, making sure that you can communicate when the Internet is shut down or your governments try to die for free speech and so on.

**Frank Corva** (0:39)
Welcome everybody, we are here at the MIT Bitcoin Expo. I'm Frank Corva, joined by none other than Calle, creator of Cashu and one of the contributors to BitChat. Calle, thank you so much for taking the time to sit down with us.

**Calle** (0:51)
Thanks for having me.

**Frank Corva** (0:52)
It's a pleasure to be here with you.
I love both of these main projects that you're working on, Cashu and BitChat. We'll start with Cashu. I think eCash, people are starting to feel, I think, a bit more comfortable with it. A few years back, it still felt kind of very new. We know that the actual technology goes back decades, but I think using it was taking a little bit of time to get people more comfortable with it. Now we're seeing wallets like Zeus start to implement it. Could you give us a little bit of, I guess, an update on the state of play as far as eCash?

**Calle** (1:19)
So the last couple of years, we've been basically focusing on building the foundation for everything else that is coming now. So we've been hyper-focused on building mints and the infrastructure around it and wallet libraries. We poured all our soul and time into making sure that that's a solid foundation. And now we're seeing more and more people to actually use those libraries that we've built, implemented in existing wallets like Zeus, for example, or just creating a new wallet out of nothing. And we're seeing just new things pop up every single month. And the most important thing is that we see a growing open source economy or community around it. And that's exactly how we expected it to happen. And it's beautiful to see that it's actually doing that.

**Frank Corva** (2:01)
Amazing. I feel like with Cashu and eCash, it felt like a very build it and they will come. And now it seems like the people are coming. Where do you see a lot of the uptake amongst what population? Or is it something that you're seeing geographically kind of distributed? Or maybe amongst, I don't know, activists who maybe use it more because they need privacy? Where do you see most of the uptake?

**Calle** (2:18)
Well, first of all, definitely people who are interested in privacy because eCash is just the best kind of privacy that you can get. So obviously, it's going to be people who understand the tradeoff between the trust that you need to put into a mint versus the privacy that you get for it. So in many cases, that tradeoff just makes sense. And in terms of the privacy that you gain, but there is also, I think, like a strong community out there who just want to build things and own the infrastructure that they're building. So I'm a big fan of all the different layer two proposals that are coming up in Bitcoin, but those are kind of centralized solutions where you have one company or another company running the sequencer, the L2 roll up or whatever that server is called in that case, but it's always that one company and it's really hard to replicate or beyond possible to replicate this for yourself. With Cashu, it's so lightweight, it's so easy to set up that we're just seeing lots of mints popping up for individual communities around the world, it's online communities, offline communities, because they can run the infrastructure themselves.
I think that just opens up a completely different group of people who are interested in building and owning the infrastructure that they're running.

**Frank Corva** (3:26)
Okay, beyond people, will it be just as easy, you think, for agents or even easier for agents to run this infrastructure? Does eCash become a critical component as far as the agentic economy?

**Calle** (3:35)
Yeah, I'm just closely watching how much is happening in that regard.
I think most of it is still expectations, so we're going to see how much is going to end up, like agents end up using money online, but we are positioning ourselves with a great focus on it. And eCash itself is very simple for an agent to understand because it's a bare instrument, you don't really need to explain the agent how lightning works and everything. And it's pretty safe for a user of an agent to give your agent a couple of sats in eCash, and that's the maximum amount of money that it could lose in case something goes wrong. So instead of setting up an account for your agent and doing all those kind of sort of steps that you would have to do in order to secure the setup, what you do with eCash is you take the data, which represents the satoshis hand it to your agent like pocket money for your agent. If the agent lose that pocket money, it's not going to be that bad.