Buenos Aires has launched a digital identity service that enhances residents' privacy through the implementation of zero-knowledge proofs (ZK proofs), which allow individuals to validate specific claims about their data without revealing the actual data. This feature is integrated into the city's app for accessing various municipal services and aims to provide the 3.6 million residents (known as porteños) with more control over their personal information.

The initiative's technology enables users to confirm their age without disclosing unnecessary personal details, such as their birthday or address. According to Diego Fernandez, the city's Secretary of Innovation and Digital Transformation, the system is designed to empower citizens with a self-sovereign identity, prioritizing privacy and security over their documents. Notably, the service does not necessarily depend on blockchain technology, though it utilizes the Ethereum layer-2 network, ZKsync Era, to serve as a security foundation.

While currently deployed in Buenos Aires, there are plans to extend similar projects throughout Argentina, with regions such as Jujuy and Tucumán already testing this technology on a broader scale.