# TapToPay Self‑Custody & Stablecoin Payments: Daily Crypto Usage | Danylo Rumiantsev | ETHWarsaw [4] - Channel: [ETH Warsaw](https://streameth.org/eth-warsaw) - Date: 2025-11-09 - Duration: 20:43 - Watch: https://streameth.org/watch/yt-nTdzxNMS3D4 - YouTube: https://www.youtube.com/watch?v=nTdzxNMS3D4 ## Description Danylo Rumiantsev from United Network shares insights from building crypto-native payment tools in card form, what they’ve learned about stablecoin spending, and what CBDCs still haven’t solved. 🎥 Recorded at ETHWarsaw 2025 Follow ETHWarsaw on social media for the latest updates! X (Twitter): https://x.com/ETHWarsaw LinkedIn: https://www.linkedin.com/company/ethwarsaw Telegram chat: https://t.me/joinethwarsaw ## Transcript Good afternoon for the rest of the people who left for the second day of this amazing conference. Thanks for having us. So today we're going to talk about the top to pay solution about stable coins about CBDC's about the future we are all going to. So I remember back in the days in 2018 I was living in Ukraine and I remember the day when Apple Pay appeared uh in one of the biggest bank uh of the of Ukraine. Uh I immediately installed it. Uh I attached my card. I went to the small grocery shop and I remember that lady she was selling I don't know water or ice cream. I tapped my phone to the POS terminal and she didn't know the Apple Pay was a thing that and she was like what what are you doing? like you tap the phone, not a card. Um and um that was the first time when I interacted in person with something like tap to pay. I've uh heard a lot before, but that was a thing that felt like magic. Yeah. When you don't need a physical card, you understand that everything that we're going to do in the future will be inside of our phone. So, uh first it was curiosity, then it was a feel of a magic and now it's a routine. So uh by the stats in European Union 81% of all the uh intore payments are done contactless by either contactless by card or your phone, Apple Pay, Google Pay. In the United Kingdom, it's more than 90% that all of the payments are done contactless by tap to pay. It means that we're all going apart from uh the physical banking cards going inside the terminals and we are all going to the future when we know what to do with uh our smartphones. Um shifting to the crypto uh we have the solutions like um crypto banking cards I would say when you can top up your card with uh some stable coins USDT USDC you can attach it to your Apple Pay I won't drop the names you all may probably know it and you can go and spend somewhere in a retail shop you can buy grocery stores but uh there are pros and cons that are great initial steps for crypto moving to the fire but anyway uh it's a Good crypto management. Yeah. When you can easily without syncing spend your USDT, the merchant will receive either euro, USD or whatever region you are and it's user friendly. Yes, people understand what is like a neo bank. People understand how to easily um deposit USDT for example. But the problem is that the whole crypto management there is under the full custody of the company who is doing the collaboration between uh the bank and them at the crypto company. uh and also the dependence on the external regulations. We all know that uh for the first years when it appears everything seemed like seems seemed like magic because I went to the shop I spent my USDT even like by usual POS terminal but after few years regulators came and say no no no you cannot do like that you should do it like this like this here are the set of rules and we understand that each country by the time they will come up with some more and more regulation and it may be a problem um and most of these cards they use stable coins, right? And during the whole like um bull runs when we had uh like for example DeFi in 2019 2020 then we had had NFTTS now we have memecoins during all this time we had a quiet stable coin revolution when stable coins became the norm. uh they started back in 2014 when the first companies tried to make some stable coins because volatility was a problem and they say okay we should start doing some stable coins and Ster was the first companies that came out from those experiments they made USDT you all know that and then when they became the backbone of uh maybe all the liquidity in 20189 of the D5 products uh they became the first product uh as a stable coin who was considered as something serious. uh after that uh circle and USDC came up uh like okay we want to comply with US regulations we want to comply with uh the governments because government governments relate u they were concerned already they didn't know what to do with that but they were still concerned uh so today stable coins they already have like the whole capitalization 250 million billions plus in capitalization the whole um uh transactions per year are trillions uh per year for all the stable coins and the whole remittance of all remittance fire stable coins everything stable coins are 3% of the whole remittance uh so governments they were concerned first and then they decided like okay we need to do something with that we need to come up with uh some uh stable coins by ourselves and then we uh found a CBDC like central bank digital currency around um like more than 130 countries they already uh like overviewing different approaches to how they run their own digital currency. Uh over 50 plus projects uh were launched as a pilots and we can outline maybe three of them in a different perspective. China I guess is the most successful one with their digital uh digital currency as the mass adoption one of the really successful projects. India is one of the uh most successful experiments. They're still running it as an experiment but more in the successful side. And Nigeria as an example of inra they have 98% of inactive wallets and it was considered a failure just because of lack of mass adoption. They didn't know how to uh make people use inra and people were not trusting them as a government. So there was a failure considered by them as well. Um and then we are moving to um uh the concerns of the government and the crypto community like okay we have uh a lot of money uh stored in crypto somewhere uh and why it is happening uh why the hacks are happening and the amount of the hacks amount of the uh money being uh stolen is uh being u like every every year it's become more and more money. So in 2024, we had $2.2 billion uh stolen from the whole like uh crypto community. In uh only in the first half of 2025, we had more than two billions already. So we're already exceeding 2024. Uh and in 2025, we had the biggest single hack in the history of centralized exchanges. I don't want to name the the company, but you all know that. So it's a big concern what is happening in the u in the hacks of the crypto community if it still remains the trend and uh according to chain analysis all these stats that I named it's uh according to uh chain analysis uh they say if all remains the same the projected loss in 2026 is around $4 billion that's even more than for the last two years. The problem comes from uh how the currencies are being stored. Yes. And uh we can made some kind of a hierarchy of uh what do we have? So first uh most of the people most of the like traders uh people who are like newbies to crypto all of us we a little bit we keep our money on exchanges on centralized exchanges. Uh it's good to have some money on exchanges but we all not we all know that it's not that safe. Yes. Especially after FTX um a lot of people realized that maybe I should keep most of my money most of my um savings not on the centralized exchange um and we're coming up to the next level as the hot wallets or software wallets. There are a lot of names but uh it means uh that you have a dedicated application uh you have your seat phrase but everything is inside your app. It's some kind of a compromise between like okay it's not an exchange but it's still your seat phrase your private key is stored inside your um mobile phone application etc. Um those who are more concerned they're like okay I need to come up with something more secure they say I will use something physical like a hardware wallet uh we'll know ledger tre treasure etc. And the problem is they're secure that there are some concerns. Of course, there always will be concerns, but um this is the most secure way for now to uh uh store your crypto, but it's too complicated. I spend a lot of time u um back in the days, I was talking to people who had money. They're like, they don't know about crypto at all, but they made some money, I don't know, buying Bitcoin early and then selling on the highs and they say, "Okay, I have like $1 million in USDT. Uh, where should I keep it?" Ledger. Okay. Can you help me to set up a ledger? Because I tried by myself. I was trying to install the ledger live. Then I didn't realize how to set up a seat phrase, how to write it down. So, it was too complicated. It felt like a rocket science to them. And uh for most of the people in crypto, it still feels like a rocket science. It's secure but it's not accessible. So what's the next step? Yes, there should be some kind of a evolution of uh how the custody is going because if the hacks of what we were talking before are still going on, we still have a problem. Uh so and user users all of us we are users. What do we what do we want? So first of all, we want simplicity. We live in the times when we are lazy. All of us are lazy. We we spend like hours like scrolling Tik Tok. We don't want to do anything. We want everything to be simple, accessible, and easy to understand. We don't want to spend hours to understand how the product works. Uh we want it to be transparent especially after some situations with hacks etc. Everything should be uh transparent how the product works. If it is some something custodial, how the money are uh uh stored, how the custody works. So a lot of like regulation stuff trust and transparency of course the privacy a lot of stuff during the last 10 years happened in the privacy of data privacy users privacy how we don't want to share our data with some third party companies all the GDPR stuff that happened in the European Union so everything related to the uh user data privacy it's also important and of course the sovereignity so when you want to keep your funds um safe it means that you need to have a control of your funds, right? It means that you want in every moment be able to do something to send it uh anywhere and you don't want to relate or be dependent on some other company uh for for them to store your money. You want to have access to your funds. So three years ago uh like we came up u we were in me and my business partner we were on a business trip in Africa and meeting the CEO of one of the biggest financial companies in Africa. Um and they don't they're not related to crypto and they actually don't like crypto at all. They told us like we don't understand it. If we don't understand it we don't want to relate it it u at all but we have a problem with the mass adoption. We we understand that we want to spread our financial tools to um our users. We still have problems with uh our central bank with the banks. Uh the financial system is not stable. So they were looking forward to some CBDC stable coin etc. And they told us like um if someone come ups with idea when the crypto is just an invisible layer and people will not even understand that it is a blockchain tool or a crypto solution they will just use it on a daily basis then it may be interesting. So the idea is that um when people are using uh the wallet there is always a trilemma like in all the blockchains like all the companies they spend a lot of time trying to solve the blockchain trma we decided why don't we create a crypto wallet trilemma yes when there is security self-custody accessibility in one form where is there is always a compromise you will never find a perfect solution but when you can use the card um as the form factor when you can use the chip on the card as the way to securely generate the private key to store the private key only on the chip of the card and then if you want to send a transaction you just need to tap a card. You don't need a cable. You don't need a laptop uh or a special software on your laptop to send the transaction. You don't need to spend 5 minutes to send uh I don't know 1,000 USDT from your from your hardware wallet. You can do it in one tap in a few seconds. And um we had a lot of lessons uh learned from the crypto before. A lot of money were stolen. A lot of money were lost just because the access to those wallets uh wallets were lost. People were not educated. People were very bullish. Uh and people sometimes forget where they store their money and the USB hardware wallets are too complex and people want to have control their money but they don't want it to be too complicated. So if crypto goes beyond all the speculation and if we calm down a little bit and if we try to understand how we can securely uh still have access to our money, how we can manage it, how we can trust ourselves with being in control of our money, then it will become invisible. Then all the CBDC projects, then the governments, financial systems, payment networks can get a lesson from us and we can together as a crypto community show them that it is not only about speculation and all the concerns about mass adoption can be solved by building sustainable tools where users control their money and where governments still may be um very confident confident about the mass adoption and how it will be used on the daily basis. So, uh thank you for your attention. Uh my name is Danilo. Uh or shortly for them. If you have any questions, please. >> Yeah. Questions? Anyone? Anyone? Anyone? How secure is this uh key on your card? >> Um it's a good question. So uh if we talk about the card uh I guess most of most of you have been at our booth if no um uh so there is a chip uh in the card and uh all the magic of the um hardware wallet happens here because uh we have made a software for the chip. The chip is already certified by uh the manufacturers who made this uh chips for banking cards. Uh so when the card is new it's empty. So there is no private key. When you tap your phone with a card to activate it, the private key is being generated on the chip and it never leaves the chip. If you want to sign a transaction, every time you need to tap it with your phone to confirm the transaction because the private key is here, it's the same when at less to confirm the transactions. Uh the same you tap here. So the question of security uh is that private key never leaves the card. The second layer is the communication between the phone and the cart. We use NFC as a first layer of technology to communicate between the phone and the cart. But NFC by itself is not a secure way because we and then we used the second layer above is a Fedo Fido. It's a protocol above the NFC uh that gives us possibility to make an encryption communication between the card and the phone. and it is used on the system level with iOS and Android to support the encryption uh of the communication between the phone and some third party device. So it's a second layer and the third we don't have any uh back end any servers. So it means that we don't store any data elsewhere but on the card. So I guess I answered your question. >> Oh there's another one. >> Hello. Hi. >> Uh my name is Arthur. I have a question about recovery. Uh recovery. Yeah. In a case of the losing this card, is there a way to recover? >> Of course. Of course. When you set up, you have a seat phrase. Uh so you write it down. Actually, seat phrase is a private key just in the friendly view for the user. So the private key itself is just letters and numbers. And the seat phrase when you first activate the cart, it's being uh displayed in our app. It's a web app or the application. So you write down your seat phrase, keep it somewhere securely. So if you want to restore, you can just restore it with a new card uh and your seat phrase. >> Uh is there a way to set up guardians or like recover from other private keys? >> Uh not yet, but in the future I guess yes, if we hear more feedback from the community. Yeah. >> Is it physically possible to access the private key? >> No. >> By the like with the chip chip? >> No. No. >> Okay. Hello. uh how long it can remain if I dig it for example in my backyard under the ground in some box like >> uh as it it doesn't has any batteries or micro electronics depending on some so I guess years or decades I can safely uh everything that can happen it maybe the chip will get some erosion under the ground uh so better wrap it with some plastic bag and that's it >> but for years I guess it will remain there >> why do you need a chip if you like like this uh physical access if you have NFC >> uh there are two NFC is just the way to communicate so actually the chip has its memory and there are algorithms so we made a software for that is running inside the chip and the NFC is the way to send the data from the chip to the phone so it's like two different things >> okay but what is like I mean the physical contacts what are they for >> uh to sign the transaction because the private is not here. >> Diffult ones. >> Ah, this one. Okay, that's a good question. So, actually uh there were there are different chips right on the market. This one we have the contact uh on the on the top just because it's a little bit thicker than a card itself. So, it should be displayed. Plus in the future uh it may be used with some kind of um uh POS terminals if we make some collaboration with some uh national payment systems or something like that to use with some contactless uh or chip payments. >> How did the manufacturers allow you to write your own code into into the chip? >> You don't need a permission to write your no you just have access to the chip. uh they give you some um like guidelines how to access uh the chip and you work with them directly. So we work directly with the manufacturer of the chip >> because like the like for an example for Visa or something like the manufacturers actually have the private key and they load it there. >> Yeah. >> So you managed to convince them to not do that and allow you to >> It's totally different because Visa and Mastercard they give their own applets. Applets means software uh that they uh made. >> Mhm. So you can use this applet only by uh a proof of visa masterard. So if you talk about the manufacturers, they give you the empty chip. We don't have anything on that. We don't have Visa Mastercard on that because that can happen only if you are certified by Visa and Mastercard and it's a long process and a very expensive process. So in this case we just have like let's say it's a small small computer with its own algorithm that can be run by. So and uh little different programs can be run simultaneously. We have made a program that is hardware wallet. If we integrate visa master card that will be another program on the same chip that can be run simultaneously in parallel >> just like in ledger you have like space multiple applications. >> Yep. Yep. >> Okay. Wonderful. Any more questions? >> No. Then thank you very much. This was quite insightful and super interesting project.