Starknet has launched STRK20, a zero-knowledge privacy framework that gives ERC-20 assets shielded balances and private transfers, according to information shared with The Block.
Summary
- STRK20 gives ERC-20 assets shielded balances and private transfers without requiring separate privacy infrastructure stacks.
- Viewing keys allow targeted disclosure for valid legal requests while protecting other users’ transaction histories.
- strkBTC provides the framework’s first live use case, adding optional privacy to Bitcoin activity.
Developers can add confidential flows without building a separate privacy system for each token.
The framework supports transfers, swaps, lending, staking, payments and donations through compatible wallets and applications. Viewing keys can also provide limited transaction records when authorities present a valid legal request.
STRK20 brings private balances to Starknet tokens
STRK20 lets users move assets between public and shielded states while keeping the same underlying ERC-20 token. A zero-knowledge proof confirms that each private action follows network rules without exposing a balance or full transaction history.
The system uses Starknet’s native proof infrastructure and Cairo-based contracts. Users place assets into a shared privacy pool, transact inside it and withdraw when needed. Starknet says this avoids creating isolated private tokens or splitting liquidity across separate markets.
Meanwhile, each participant registers an encrypted viewing key. An independent auditing party can use it to reconstruct one user’s activity after receiving a valid legal or regulatory request. Other accounts in the pool remain hidden.
“This is practical privacy in the truest sense,” Starknet Foundation growth vice president Damian Chen said. He described the design as a way to preserve public confidentiality while retaining a route for required disclosure.
Starknet said STRK20 differs from a mixer because privacy remains part of the asset’s normal movement. Mixers usually send tokens through a separate service to obscure transaction history. STRK20 instead adds shielding to supported wallet and application flows.
strkBTC becomes the first major STRK20 use case
strkBTC became the first asset built on STRK20. The Bitcoin-backed ERC-20 token offers public and shielded modes, allowing users to hide selected balances and transfers before returning assets to a transparent state.
The rollout supports shielding through Ready X and Xverse wallets. Starknet is also expanding private swaps through avnu and Ekubo, while lending through Vesu and staking through Endur form part of the wider plan.
Some parts of these DeFi transactions may remain visible. Starknet notes that amounts routed through public liquidity can appear onchain even when the direct link to a user’s wallet is hidden. Privacy also strengthens as more users enter the shared pool.
Starknet expands a privacy plan announced in March
As previously reported by crypto.news, Starknet introduced STRK20 in March for confidential ERC-20 balances and selective disclosure. Its v0.14.2 mainnet upgrade later added native proof verification for encrypted balances and private transactions.
StarkWare chief executive Eli Ben-Sasson said zero-knowledge systems could allow future investigations to request narrower information. The approach has not yet faced broad regulatory testing, and institutions will still need to assess its legal, security and operational controls before adoption.
