How Argentina is using zero-knowledge proofs to revolutionize digital IDs

Argentina is recognized as a leading crypto adopter in Latin America. On top of accepting Bitcoin as a legal tender, the country has welcomed several novel blockchain innovations—from the official fan token of its national football team to stablecoin adoption amidst soaring inflation. 

Now, its capital Buenos Aires has welcomed yet another breakthrough: a digital identity service supported by zero-knowledge (ZK) proofs—offering a whole new level of cryptographic security. 

A zero-knowledge proof is a way of verifying a statement is true without revealing the statement itself. So, zero-knowledge identity proof is a system of authentication where one person can prove they are who they say they are without giving away who it is that they are.

The introduction of this system makes Buenos Aires the world's first city to include blockchain and ZK cryptography in digital identities that are self-sovereign. 

Buenos Aires es una ciudad pionera en innovación y la incorporación #QuarkID a su plataforma de identidad digital les otorga a las personas el control sobre su información, con un respaldo de seguridad en blockchain a través de la tecnología de @ZKsync Era.

— QuarkID (@Quark_ID) October 22, 2024

According to Diego Fernandez, Buenos Aires’ secretary of innovation and digital transformation, the efforts were implemented “to create a self-sovereign identity system so that citizens can have privacy and security over the documents they acquire ownership of”. 

CoinDesk reported that the ID service QuarkID has been incorporated into miBA, which is Buenos Aires’ application for accessing municipal services and documents. Per Globe News Wire, all active miBA users receive a decentralized digital identity (DID) secured by the QuarkID wallet. 

While keeping information safe from the eyes of others, the cryptographic technology will alert users that the government truly authenticated a document. QuarkID will also let citizens verify credential accuracy without exposing their personal data out in the open. 

The app accepts over 60 kinds of documents, including birth certificates and vaccination apps. More document types—such as driving licenses and high school diplomas—will be made available in the months to come. 

CoinDesk noted that no third party can gain control over the documents and track why, how, or when a credential is used. 

With this, porteños—or Buenos Aires residents—need not worry about data leaks and hacking. In fact, not even QuarkID or the government can track credential usage. 

This added security significantly reduces the risk of identity theft, as reported by CoinDesk. 

Buenos Aires is the first city to issue decentralized IDs to its citizens!

By integrating @Quark_ID into the miBA platform, over 3.6M Buenos Aires citizens now have control over their documents via blockchain and ZK proofs, with Era serving as the settlement layer.… pic.twitter.com/QS4lhvjpE8

— ZKsync (∎, ∆) (@zksync) October 22, 2024

Behind ZK proofs is an overarching blockchain known as ZKsync Era. Unlike networks such as Bitcoin and Solana, ZKsync Era is a Layer-2 blockchain that runs on top of another network to boost the main one's efficiency and scalability. In ZKsync's case, the blockchain it enhances is Ethereum and it does so through its complex yet innovative ZK technology. 

ZKsync revealed in a press release that thanks to its ZK proofs, only important information is relayed in the identity system. For example, the age of an individual can be confirmed even without revealing details like the person's full birthday or specific document code. With this, maximum privacy is ensured while verifiable accuracy is maintained. 

Moreover, the added security will also allow citizens to have total custody over their virtual credentials, which are secured by biometric encryption and stored in their devices. 

In light of this development, Jorge Macri, Buenos Aires’ Chief of Government, noted that “the incorporation of zero-knowledge blockchain technology into the City's digital identity system is an unprecedented milestone that positions [them] globally and once again demonstrates that the City of Buenos Aires is at the forefront of innovation”.

The chief added that “adopting new technologies that simplify citizens’ processes and grant them full control over their information is a fundamental step to continue offering more secure and transparent digital solutions.” 

With this milestone, up to 3.6 million citizens now have upgraded, blockchain-based credentials without needing to delve into the nitty-gritty details of the complex technology that backs the system. These users may simply reap the benefits of enhanced usability, feature updates, and reduced wait time, among others. 

Fernandez also noted that “by giving residents control over their identities, [they're] not only improving privacy and security, but [they're] also setting the foundation for a future where personal data ownership is a basic right, protected by advanced zero-knowledge-based cryptographic proofs.” 

The digital ID system also unravels opportunities for different use cases. These include verifying benefits for region-specific residents, sport affiliations, and voting eligibility, among other possibilities. 

Not to mention, QuarkID's open-source nature will make it easy for any organization or city to adopt it. 

While all governments own the data of their citizens, Argentina's capital is the first to let go of such control through this novel system. This marks yet another milestone in the country's blockchain journey.