QuarkID: Decentralized Identity for 3.6 Million Residents

The Government of Buenos Aires has deployed QuarkID, a blockchain-based digital identity system built on Sovra’s infrastructure, to 3.6 million residents.¹²³ Citizens hold verifiable credentials on their phones: birth certificates, proof of residency, academic records. No centralized database holds their data. No single authority can revoke access.

Architecture

QuarkID uses a ZK-rollup backbone to anchor decentralized identifiers on Ethereum. Each credential is issued by a government authority and held by the citizen in a mobile wallet. Verification uses zero-knowledge proofs: enough to confirm a claim without revealing the underlying data.

The architecture is privacy-first by construction. There is no database to breach because there is no database.

Context

Argentina has dealt with identity fraud, bureaucratic overhead, and fragmented record systems for decades. Buenos Aires adopted QuarkID because it solves an operational problem: issuing, holding, and verifying official documents without building another centralized system that becomes a target and a bottleneck.

The deployment started with the Buenos Aires digital ID (miBA) and expanded to academic credentials, proof of address, and civil registry documents.¹

Scale

Once identity infrastructure is in place, subsequent services—voting, healthcare access, licensing—build on top of it. The initial deployment is the hardest part.