Secure & Compliant Data Management

Hackathon Winners Bring Privacy To The Future Of Digital Payments

Secure & Compliant Data Management | Blockchain | PayString

What if you could send and receive money as easily as an email? No more reading off your IBAN, or memorising the back of your credit cards. No more downloading a completely new mobile payment app that you’ll PayStringSecureLogoonly use once to pay back a friend for dinner. If money worked like email, we’d be able to send it to each other regardless of the
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it doesn’t matter, after all, whether you prefer Hotmail or Gmail, emails are universally compatible. We’d be able to use money as organically as our own given names with unique identifiers that we, well, actually identify with. Thanks to PayString, that future might be just around the corner and thanks to SnT’s Dr. Wazen Shbair and his team, that future is going to be a whole lot more secure.


PayString is an open-standard protocol that is creating universal payment identifiers that work like email (something like this: name$ When a consumer first makes a PayStringSecure, they upload all of the banking and wallet details that they want to link to it, and they are ready to go. When it is time to send or receive a payment, they can use the PayString user interface to send money to another PayStringSecure. At the end of the day, this system allows for complete flexibility. You can send Euro to a Bitcoin wallet. You can send USD from your PayPal account to a friend who prefers using Wise (formerly TransferWise). PayString’s simple, open-source interface breaks down the barriers that created silos in the mobile banking market, introducing the truly independent and universal identification standard like email addresses or phone numbers that will give consumers the ultimate freedom of choice in a rapidly growing market.

“Privacy is so important. It was obvious to us that we had an opportunity here to come up with a solution that could have a big impact."

PayStringSecure team
PayStringSecure Team

Until now, there was just one problem: it wasn’t private. “When the Paystring BlockSprint Hackathon began, any anonymous user who had another user’s PaystringSecure could use it to look up that person’s bank details,” says Shbair, Research Associate at SnT. “Privacy is so important. It was obvious to us that we had an opportunity here to come up with a solution that could have a big impact.” The catch was that as participants in Paystring’s 25 September 2020 BlockSprint Hackathon, Shbair and his team of doctoral researchers, Flaviene Scheidt de Cristo and Lucian Andrei Trestioreanu, had to do it in just two weeks.

“I am very proud of the results the team delivered here."

The winning solution Shbair and his team developed, called PayStringSecure, is an elegant one. The team created a novel “notary” system that can link a PayStringSecure to a unique and verified Digital identity (DID). With identities securely established and linked to the PaystringSecure, users can create a white list of Paystring users who have permission to access their information. The DID’s technical infrastructure ensures that only the whitelisted users can decrypt the information. The best part? You still only need to remember your PayStringSecure, and all of the technologies used in the solution are freely available as community-supported open-source tools.

“We were looking for a novel and innovative solution that keeps the spirit of PayString ‘Make Money Move Like Email’. This meant avoiding an approach that put more burdens on the PayString users. We are proud to have successfully integrated the cutting-edge technology of Hyperledger Indy’s decentralized digital identity into the PayString reference server in just two weeks,” says Shbair. “Now we have a full working prototype of the enhanced privacy-preserving PayString server.” 


Prof. Radu State, who helped lead the group and directs the SnT’s ongoing partnership with hackathon co-sponsor Ripple, said of the results, “I am very proud of the results the team delivered here. It is a good example of the research ingenuity and excellence that we as members of Ripple’s University Blockchain Research Initiative (RUBRI) project have come to expect from our work every day.”

People Partners in this Project​

Radu State
Radu State
Lucian Andrei Trestioreanu
Lucian Andrei Trestioreanu
Flaviene Scheidt de Cristo
Flaviene Scheidt de Cristo
Wazen Shbair