StarkWare has introduced Private KYC on Starknet, a demo that lets users meet know-your-customer checks without giving companies full copies of identity documents. The system uses zero-knowledge STARK proofs and STRK20 privacy features to confirm specific facts, such as age, valid credentials or eligibility, while keeping passport details and addresses away from company databases.
How Private KYC works
The process starts when a user scans a passport on a phone. The phone camera and NFC chip verify that the document is genuine and signed by its issuing authority. After that, users can encrypt identity data to a Starknet wallet. StarkWare said users can register selected attributes in a public onchain registry. Verifiers can then check zero-knowledge proofs against that registry without seeing the identity data behind them. "Identity checks today ask for your whole document when they only need one fact," said the Starknet team.
Data breach risk shapes the rollout
The launch comes as companies face growing costs from storing personal data. KYC checks often require passports, addresses and other records, which create risk once they sit inside company systems. The Identity Theft Resource Center reported 3,322 U.S. data compromises in 2025, a record total and a 79% increase over five years. IBM also placed the global average cost of a data breach at $4.4 million in its 2025 report. Crypto users have already seen the risk of exposed identity data — Ledger suffered a 2020 breach that exposed more than 1 million email addresses, along with names, phone numbers and physical addresses. "Private KYC shows that verification and privacy aren't a trade-off," said StarkWare.
STRK20 provides the privacy layer
Private KYC builds on Starknet's wider STRK20 privacy framework, which lets ERC-20 assets use shielded balances and private transfers while keeping a path for lawful, targeted disclosure when required. Starknet launched STRK20 privacy for ERC-20 tokens earlier this month. The system lets users move assets between public and shielded states, while zero-knowledge proofs confirm that private actions follow network rules. Private KYC applies that same approach to identity checks — it does not remove KYC, but limits what companies receive when they only need to confirm one fact.
Self-custody model sets it apart
The system uses a self-custody model tied to a Starknet wallet, meaning users keep control over encrypted identity data instead of sending complete files to every platform that asks for verification. The model differs from World ID, which also uses zero-knowledge proofs but has faced criticism over biometric checks through iris-scanning hardware. StarkWare's demo focuses on passport-based checks, phone verification and selective disclosure through Starknet. Adoption will depend on legal review, app support, verifier trust and security testing.