BackTogether

Inspiration

ComeTogether is a start up that gives control of the entire ticket lifecycle to event organizers, with the power of blockchain. As events are particularly impacted by Covid-19, we were looking for ways to adapt to this new reality. We decided to use our event ticketing technology as the foundation for COVID-19 passports, which in turn can provide an immediate route, to safely return back to the full spectrum of economic and social activity, including events. The urgency of the solution became even more apparent, when we realized that it can help bring recovered health workers back to the frontlines safely.

Moreover, as most of the team is living in Greece, we experience first hand the crush of the tourist season, that makes up for 20% of the country's GDP. Of course, tourism is not the only industry impacted as a result of this crisis; we cannot overlook retail, airlines, sports and entertainment events, restaurants, etc. The global losses due to the COVID-19 crisis are estimated from $5.8 Tn to $8.8 Tn. This is why our society cannot afford to quarantine people that have already recovered from the virus, or have been vaccinated when a vaccine is developed. Additionally, people who tested negative with a COVID-19 test within the last few days, are also non-contagious.

The added value proposition of our ticketing solution, ComeTogether, is that it combats ticket fraud and scalping. Similar requirements exist for COVID passports. They should be non transferable or sellable and impossible to forge. This is why the passports are delivered through ID document verification currently. Next step is to support biometric validation (face, fingerprint). Hence the passports will be always uniquely tied to each citizen.

What it does

BackTogether’s COVID-19 passport solution, provides a way to validate both COVID-19 and antibody test status. Health centers (hospitals, mobile health units, etc) test citizens with serology tests for the presence of antibodies and for COVID-19 tests (such as RT-PCR) for the presence of the virus. Many tests in the market, test for both simultaneously. BackTogether provides archival for all three cases (COVID tests, antibody tests, COVID & antibody tests). The health worker that performs the test enters the citizen’s id, the test type, id and results and the issuance date. This data, along with metadata for the passport issuer, are currently stored encrypted on the blockchain and consist the citizen's COVID-19 passport. The passport can then be validated, by scanning the owner’s ID document. We are working with health authorities to approve BackTogether as an appropriate test archival solution. In this case, the health authorities may authorize and sample check the health centers that issue the passports. However, we are also serving market demand from businesses and citizens, for an immediate, unofficial solution.

There are important benefits for all stakeholders: States can restart their economies, open their borders and have vaccination data for the population, in a non-privacy invasive way. Health centers provide an ideal way to store test data. Citizens are able to prove their status easily and return to the full spectrum of economic and social activity. Moreover, they will be able to monitor their vaccinations and get reminders. Businesses such as events, airports, airlines, stadiums, museums, hotels, restaurants, insurance companies, crowded offices, public services will provide the demand. BackTogether will allow them to offer their standard set of services to passport holders, without risking public health and a different set of services, with extra hygiene precautions, to the rest.

How we built it

We built it by using our already developed technology for ticketing, which has been successfully used in 14 music events, as the foundation. Our tech stack includes: EOSIO smart contracts written in C++, MongoDB and Node.js server, eosjs, React Native for the mobile app and the scanner.

The smart contracts are currently deployed on Jungle EOSIO testnet. Currently the smart contract stores the passport data encrypted on the blockchain. Storing the data hashes on the blockchain is not the best practice, as the hashing algorithms may be compromised in the future and GDPR compliance is impossible, when the data are stored on a public blockchain. However, we will refactor this and store data on IPFS, while storing the IPFS hash on the public blockchain. The refactored version will also be compliant with the W3C Verifiable Credentials standard, enabling interoperability with other similar solutions and ease of integration with applications that use W3C DiDs and W3C VCs. In this direction we have already developed the first implementation of W3C DIDs for EOSIO Blockchains. Next step is to implement the passports as W3C Verified Credentials and integrate with the DIDs.

The use of EOSIO blockchain technology, with a private IPFS - public EOS Main-net architecture, which is compliant with the W3C Verifiable Credentials standard, ensures:

Data security and along through encryption- data privacy,
Auditability as hashes of the IPFS are stored frequently on the public blockchain. Saves the certificate from political implications (no need to trust central servers/authorities).
GDPR compliance.
Very high scalability.
Negligible costs 
Interoperability with the W3C VC ecosystem.

Challenges we ran into

The cost and scalability required for this solution to scale globally were initially a concern. The cost of deploying the solution on EOS Main-net is around 200,000 Euros for 10M certificates and its scalability, can reach up to 10,000 transactions per second. We figured that such cost would be significant; hence we designed the new private IPFS - public blockchain architecture, where only the hashes of the private IPFS network will be stored frequently on EOS Main-net, enabling much higher scalability along with negligible cost. The same architecture allows us to stay GDPR compliant, as data can remain stored within the EU geographically, if that's where the IPFS network’s nodes are hosted.

Another challenge we ran into, was finding a viable business model. As the code will be open source to have the necessary transparency and auditability, many usual business models don't apply. However offering support to health authorities to help them securely and efficiently run an IPFS node, will provide additional value to the ecosystem and can create a viable business for us. Another potential source of revenue can be a premium offering of the app, with extra features for the validator businesses. Making money is not our first priority in this dire situation, but rather to contribute our part in improving it. However, creating business sustainability will allow us to continue innovating and improving the solution in the future.

Accomplishments that we're proud of

Launching ComeTogether to the market, being among the first companies worldwide to issue tickets for live events on a public blockchain, offering unprecedented value to event attendees, organizers and performers. Among the winning projects in the 1st and 2nd Antivirus Crowdhackathons, as well as in the official Greek government hackathon. Securing Emergency Help, a health services company with more than 80,000 customers, as our first paying customer.

What we learned

To work with ML Kit for Firebase (text and face recognition). About W3C Verifiable Credentials Data Model as well as the eIDAS regulation.

What's next for BackTogether

We will complete the compliance with W3C Verifiable Credentials Standard. In the context of EOSIO Virtual Hackathon we developed the first implementation of W3C DIDs for EOSIO Blockchains. Next step is to implement the passports as W3C Verified Credentials and integrate with the DIDs until September.

By the end of 2020 we aim to add biometric validation of the passports. The validation will be based on Zero Knowledge proofs, in order to allow for biometric data sovereignty and privacy.

Another really important next step for us, is to integrate BackTogether into ComeTogether and enable more events to take place safely.

We are launching the MVP in July and immediately starting the issuance of COVID passports for people tested by Emergency Help. We are also marketing BackTogether to other health centers and companies that perform such tests, listening carefully to their requirements and building the MVP accordingly. Greece provides a good opportunity for BackTogether, as the country has kept a low number of cases and now is carefully opening to tourists, which prefer it, due to its green zone status, in regards to COVID-19. However, in order to keep the number of cases down, the authorities are looking into the direction of testing and other precautions, so a solution like ours is needed.

We are currently also working on raising the awareness to public authorities, in order for them to have the solution approved in their jurisdictions, as an appropriate way to store and validate COVID and antibody test results. Winning on two antivirus hackathons is connecting us with public authorities in Greece, such as the Region of Attica and the Ministry of Culture and Sports to pilot in their jurisdictions.

The urgency now is for SARS-CoV-2, but the solution will be expanded to include more pathogens in the future, as well as a vaccination monitoring tool, with reminders to adhere to the recommended vaccination timelines.