- Smart Brazilian Fiat-to-Crypto over Zcash

Hello Zcommunity,

Yesterday we published this proposal, and I’m here for any question.

I endorse that it is an unique moment to instruct and create tools to help the massive amount of non-english speakers brazilian crypto-adopters to be aware of their privacy, once our national bank system just changed it’s methods (and controls) and the search for cryptos grows exponentially up as our fiat goes down (luckily not drastically as in Venezuela) and we believe to have skills to build a solid rock around there, to start.

This humble proposal would allow a small team to take the next 2 months, starting ASAP, to leave their boring works for a while and fully focus on this: finish our platform that automates BRL:fiat to crypto using our existing pool of sellers, doing it over the new brazilian bank system, Zcash and atomic swaps.

Plus, would be great to have a longer-term relationship with this community about our shared missions.


Thanks, @extrapo - I’d love to get more community eyes and weigh-in on this, also posting what I posted to the ZF Grants page here:

I would color the ZOMG as intrigued but needing more details in order to know that execution will be there, and to approve this. From reading this post, and the Zcash Forum post, it’s also the case that there’s a mix of native languages in the mix and so we’ll all work to be mindful of that.

To try and summarize, what you’d like to build is two-part:

1) BRL to crypto bridge, using a “fiat mining” mechanism" to incentivize onramps to take BRL and provide XYZ-cryptocurrency in return 2) Cryptocurrency Exchange / DEX

Is the above correct? If no, where did I miss?

If yes, then we have questions as follows:

1) Where do you plan to use ZEC specifically in your processes? Are these exclusive or optional integrations of ZEC? -You make mention of ZEC in the fiat onramp, as well as at the center of an atomic swap mechanism for privacy-preservation. Further detailing both situations (e.g., is ZEC core to the system, or optional among a set of other cryptoassets?), as well as any other uses of ZEC would be helpful.

2) Since this appears to be an application from an existing service in Moeda, how much is already built? How much do you still need to build?

3) Is what you’re buidling an exchange (centralized) or a DEX?

4) For what’s built, is there a way you can share volumes in fiat and exchange flows? The user #'s are helpful, but knowing the flows through the system would be great – if you’d like to keep that private, we can find a way to move the answer offline.

We’re likely to have more questions if this continues to track well.

thanks again, Chris

Se for mais fácil, eu falo português e posso ler e responder as suas perguntas em português tambem.

(Porém, inglês seria melhor pelos outros do ZOMG, e pela maioria dos participantes aqui.)

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Hi Chris,

Glad to have some feedback, and sorry if it isn’t so clear. Our plan is not so complex, comparing to the zkSNARKs alchemy :slight_smile:

To clarify your first question, I share here a high-level overview of our next-generation model exclusively using Zcash as a layer to protect our decentralized “fiat miners” >>

Moeda.Casa does not have any “public” service today, it is still a closed research & development experiment. This proposal would fund some of us to build and deploy an open platform for what we have being doing in closed groups, slowly expanding. I mentioned that we’ve used a ETH-XRP approach before and I’m here willing to bring a Z-Privacy alchemy re-engineering. Now in early stage, we had processed an average of 50 trades per day with a dozen fiat-miners, with limited 100-500 BRL per trade. The next-generation model will have it all indexed, and potentially transparent. All of this is just possible since 16-nov-2019 with the new Brazilian Bank system (PIX) and a very few new Fintech banks allowing OpenBank APIs.

We would call it now a curated-DEX, because the Pool of Sellers are known and just join over friends-of-friends invitations. But bringing Zcash to the game, as this proposal evolves, would allow us to enhance mechanisms and blindly scale.

Our closed git repo has many fragments of different codes and libs we have being experimenting and building for the last 3 years, also as crypto miners, and I believe that 320 hours of work for 3 people (8x5x4x2 @ pandemic winter) is enough to develop something unique, in terms of project. We dream it become a popular method in Brazil and bootstrap a safe far-from-exchanges source of crypto and inspire people (not just users) into more-than-ever-needed privacy.

We are mostly long-term linux hackers, now providing crypto to friends-of-friends, willing to push new levels of automation and privacy in the country. We do believe that crypto will play an important role in Brazil over the next years and want to be part of that.

I have being reading the forum and understand the frustration of projects that were funded in the past and just disappeared or dismissed the promised integrations. We have long-term plans with Zcash, our favorite crypto project, and even have other ideas for other proposals.

Hope we go far.
Thank you

Hey Holmes,
Reading the forum this days I think I recognized you from a workshop we did together in Rio de Janeiro in 2015. There was a guy with a 3G antenna equipment presenting how to build a pirate cell phone station… we were very few hacktivists in a room at Casa Nuvem. I worked with TTC on that time. For sure we have good real-world common friends there and your portugues is already better than my english :slight_smile:

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I fear this still isn’t totally clear to me, but I’ll talk it over with the other ZOMG members when we meet next Wednesday to see if they’re understanding better than me, and someone will get back to you from there. Thank you for your work and interest!

Oh, awesome! I remember that workshop! Seeing old nokias connected to a software defined radio was a special feeling :slight_smile: Que saudades da nuvem!


The only anonymous way to buy cryptocurrencies in Brazil

I think this might be a language thing. are you sure you are not talking about KYC and AML rather than privacy>

ballast = meta data? because you are adding it with the way you are using zcash. It is probably trivial to link the eth to the zec, to the new coin, to you.

Immediate - Our Smart Contract runs automatically after your deposit, and your currency is sent to your wallet in minutes.

[/quote] so I send eth request btc, you are leaking even more meta data.

Which specification did Mythrx audit to i cant see it on their website.
Also just because you dont have a hotwallet doesnt mean I cant divert the payments.

So can I get fiat from you or are you more like shapeshift? just without the KYC.

Franco - No marketers, advertisements or advertisements. 

Where does privacy start and blind trust end? What proof is their that you are not changing the deposit addresses and skimming off the top or just straight up stealing?

How do I do a transaction? someone did one 3 days ago.

| 20-01-2021 | 38 transactions processed | is powered by Zcash


I buy some eth, send it to your smart contract whcih then sends it to my z address? do you z2z the address first?

What are you doing about metatdata leaks? your server, and the exchange know whats happening.

Is the site operational? it says it has done 38 exchanges.

I can see a few problems with the workflow of this. specifically

You need another z2z in there before z2t or it is not private.

Hi mistfpga,

Good questions. I’m happy to try to elucidate.

The website as it is now still reflect some old things. Was exactly during the discussions that lead to the intentions of a re-architecture using ZCash that we came to this proposal. You can see the Moeda.Casa to come as a union of sellers willing to have an unified and safe method to provide crypto in the most private way direct from fiat BRL. I, by myself, have being victim of scams in Brazil trying to buy crypto out of Exchanges… reason why I “found” this trustful group of sellers years ago and now I’m pushing for a shared z-solution.

I think this might be a language thing. are you sure you are not talking about KYC and AML rather than privacy. ballast = meta data?

“Ballast” might be the wrong translation. Probably “trail” or “trace” is the way to express it. A common worry here is that traces’ from BRL transfers to known Exchanges can be (even retroactively) taxed. Transactions to a pool of “random” sellers would solve that. Nothing will proof it is a crypto being traded. Despite the benefit of having a ~4 seconds transactions now, this new Central Bank System (PIX, 16-nov-2020) brings new unprecedented levels of monitoring and control. “Our” Ministry of Economy have being talking about taxing any E-Commerce transaction, for example.

In this last 10 weeks, the new system has being used in insane ways, since someone’s PIX address can be found by mail or phone, some are using it to send 0.01 cents “PIX messages” to others (a bit like without the privacy side) and the Central Bank are being questioned to allow accounts to block others accounts, as in a Social Network… :smile:

Which specification did Mythrx audit to i cant see it on their website.

I don’t agree, as well, with the Mythx part on the actual (soon old) website. A developer used it as a proof of safety for his contract-based solution, but it was just a debugging tool. It’s gonna go out.

Also just because you dont have a hotwallet doesnt mean I cant divert the payments.

It is a good point, but I believe it still important to push users to have the knowledge to take care of their own wallets rather than outsourcing it. By ingenuity, I have seen people letting their cryptos on services like paxful or localbitcoins just to avoid official Exchanges, believing it is safer. Anyhow, who store the cryptos are the Sellers and the Buyers, Moeda.Casa just make the alchemy in between.

So can I get fiat from you or are you more like shapeshift? just without the KYC.

For now you could not get fiat from us, but it could become possible, depending on how our model evolves.

What proof is their that you are not changing the deposit addresses and skimming off the top or just straight up stealing

We have to think about that. A proof was never requested because the requested crypto always arrived :slight_smile:

I buy some eth, send it to your smart contract whcih then sends it to my z address? do you z2z the address first?

Nopz! The system for now only provides a BRL->crypto solution.

How do I do a transaction?

It needs a PIX-enabled BRL Bank account in Brazil.

What are you doing about metatdata leaks? your server, and the exchange know whats happening.

The server can log it, right. It is to be discussed if we should just destroy it from our server once the user confirms/clicks that it was received. Instruct users to use TOR or even having it as a hidden service are on the radar.

You need another z2z in there before z2t or it is not private.

The “Send $XYZ value in ZEC to z-addr” comes from a z-address from the Seller :wink: But it is true it is not so clear in the diagram.

We are reflecting on many solutions and possibilities to this new Brazilian system, but also have many questions. That is why this humble fund would provide time to some Research, beyond Development.

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Ahh I get you now.

So I have some BRL, we meet IRL, you buy some zec, z2z it, z2t it, then t2btc or whatever? like DiFi exchanges, right?

@extrapo I am pleased to inform you that your proposal has been approved!

Funding is approved for 2 months and we would like to reemphasize the need for your system to use the Shielded pool (Z-addresses) as much as possible to protect users. We would also like you to follow up with a public presentation (hangouts/zoom/youtube) when your system is working so the community can better understand.

You should receive an email explaining next steps (including KYC requirements) to receive payment from the Zcash Foundation.


All goes online, mostly on Telegram groups for now. Sellers have their ways to have ZEC, our system generates a payable PIX QR-code and the magic goes…

A comemoration is gonna happen this Sunday! :wink:

We are very glad to be able to work on it during February and March, and help to develop new methods and models for financial privacy and decentralization, inspiring more Zcash users in South America.

First week of April we organize a public presentation, sure!

Also releasing a video presenting it in brazilian-portuguese, as suggested by @holmesworcester in the 1-20-2021 meeting minutes.


Hello community!

This is an update from the Moeda.Casa team;

Many things happened last 10 weeks,

  • We are running and controlling a Tor and our own Zcash node, integrated in our system.
  • The facebook page where we have admins and beta-testers jumped to 19.6k members.
  • We have been really busy polishing this beautiful from-scratch proof-of-concept system last days… lots of back-end and UX!
  • We developed many libs for our model and integrated 6 distinct APIs in between the Brazilian Central Bank, Swaps, the Zcash node and prices estimations.
  • Brazilian Central Bank announced plans for a digital Brazilian Real; remembering we are the 12th biggest economy in market cap, and 6th in world population.
  • Since we started to discuss lots on the nature of values and prices and are gathering a multidisciplinary team, we started to organize under ミ.xyz
  • It is working! People can buy a multitude of tokens while we provide and manage a intuitive BRL->Zcash->XYZ solution via the new brazilian payment system PIX/QrCode.
  • The code is still private at our repository since we wanna do a in-between-friends audition before release.
  • We are now changing our naive deploy approach into a continuous integration process, with the help of a new DevOps friend/member, changing the way we do the “updaters” cron jobs, and doing restrict small-scale tests and experiments before it gets wild.

Soon we get back here with more information (and the promised video!)





Excellent update, looking forward to the video!

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Very nice :+1:

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@extrapo can I get an invite? I’d love to try it out!

Opz! I answered you in private and forgot to bring it public here: the website is open for beta testers to everyone with the link since 2021-03-16 - our first full process done to an unknown user.

Hey all!

Here we are, surviving intense months where many of us lost relatives - COVID hit hard in Brazil - but, with a little gap, finally vaccinated and bringing this international presentation, sharing many things that we have been thinking and carefully elaborating in the previous 6 months.

This is a Deep Presentation of 40 minutes spread into 5 parts in which

  • I present myself and previous communities experiences that lead me to join the Zcash Community this year.
  • The concepts from this experimental project called Moeda.Casa
  • Showing the web system in itself, and updates.
  • Next Zteps and ideas into privacy & decentralization using Zcash as a distributed privacy layer.
  • The ΚΣ Team behind it.

Deep Dive into Moeda.Casa @ Kripto.Solutions - YouTube

You should also check - if interested.

After some community feedback - lots to digest! - over the next days, we are gonna make a new Grant Proposal to be able to extend our Team’s Research & Development.

PS: English is not our mother language, feel free to ask if you don’t understand, and to suggest corrections on the docs.