Starknet Launches STRK20 Privacy Layer for ERC-20 Tokens

Starknet Launches STRK20 Privacy Layer – Shielded ERC-20 Balances and Transfers Introduced on Ethereum L2

Key Takeaways

• Starknet has launched STRK20, a note-based privacy layer for ERC-20 tokens on its Ethereum layer-2 network.
• The framework enables shielded balances, private transfers, and private swaps verified by zero-knowledge proofs.
• An encrypted viewing-key mechanism allows transaction tracing in response to valid legal or regulatory requests.
• STRK20 applies to existing ERC-20 tokens on Starknet without requiring a separate privacy-native asset.
• Broader DeFi integration and cross-chain access are planned but not yet available.

STRK20 Goes Live on Starknet

Starknet has rolled out STRK20, a privacy framework designed for ERC-20 tokens on its Ethereum layer-2 network. The launch marks the first phase of a system the network has been building since its v0.14.2 protocol upgrade in April, which introduced native in-protocol proof verification.

With STRK20, you can shield ERC-20 token balances and conduct private transfers and swaps directly on Starknet. The system is structured as a note-based privacy pool rather than a mixer. When you shield tokens, they are deposited into a pool and represented as encrypted notes. These notes form the basis for subsequent private transactions.

The framework is designed to operate at the wallet level. At launch, it supports shielding, private transfers, and private swaps. Additional decentralized finance use cases, including private lending and borrowing, are not yet live.

How the Note-Based Privacy Model Works

STRK20 relies on zero-knowledge proofs to validate transactions. When you initiate a private transfer, the system spends existing encrypted notes and generates new ones. Each transaction must prove several conditions: that the notes being spent exist, belong to the sender, have not already been spent, and that the total input and output amounts match.

These conditions are verified on-chain before the pool state is updated. Public observers can see encrypted notes and certain required protocol metadata. However, they cannot see the sender, the receiver, the transferred amounts, or which balances were used.

By using this structure, Starknet separates visible on-chain data from sensitive transaction details. The encrypted notes replace transparent token balances with representations that require cryptographic proof for validation. This approach distinguishes STRK20 from mixing services, as the system is based on structured notes and proof verification rather than pooling and redistributing funds in a way that obscures origin through aggregation alone.

Compliance Mechanism Built Into the Design

STRK20 includes an encrypted viewing-key framework intended to address regulatory requirements. Under this model, a third-party audit firm holds a viewing key. This key can be used to trace the transaction history of specific users if there is a valid legal or regulatory request.

The mechanism is structured so that uninvolved users are not exposed during such a review. Only the transaction history tied to the relevant request can be decrypted and examined. Starknet describes this approach as private by default, but accountable when required.

This design mirrors compliance-focused disclosures built into other privacy-oriented protocols, including Aztec and Aleo. In each case, privacy features are paired with a mechanism that allows selective disclosure under defined conditions.

Positioning Within the Current Privacy Landscape

The launch of STRK20 takes place at a time when on-chain transaction privacy is receiving increased attention. According to the source material, Zcash recently disclosed a counterfeiting flaw in its Orchard shielded pool. Following that disclosure, the price of ZEC lost more than half its value. A formal Ironwood upgrade, aimed at restoring supply verification and adding formal proof verification, is targeting a late-July mainnet date.

At the same time, other networks have introduced privacy-focused features. Aztec Network shipped Nyx v2 earlier this year, enabling private accounts governed by Ethereum keys. Sui launched a confidential-transfers feature in public beta this week. As a result, three distinct layer-1 and layer-2 networks are now offering transaction-level privacy simultaneously.

STRK20 differs in one structural aspect. Rather than requiring users to move into a separate privacy-native asset, it targets existing ERC-20 tokens on Starknet. Any ERC-20 on the network can be shielded through the same pool. This design avoids fragmenting liquidity across different privacy tokens, as shielding occurs within a unified framework.

What Is Not Yet Available

The current implementation focuses on wallet-level functions. Private lending, borrowing, and deeper integration with decentralized finance applications are not part of the initial release.

Starknet plans to open-source the wallet application programming interface and release a software development kit for builders in a future phase. These tools are intended to allow external developers to integrate STRK20 functionality into their own products.

Cross-chain capabilities are also planned but not yet live. According to the source material, the goal is to enable users on Ethereum and Solana to access Starknet’s privacy pool without manually bridging assets. At launch, no adoption metrics, wallet counts, or shielded volume figures were disclosed.

Our Assessment

With the launch of STRK20, Starknet has introduced a privacy layer that enables shielded balances, private transfers, and private swaps for existing ERC-20 tokens on its layer-2 network. The system uses zero-knowledge proofs for on-chain verification and incorporates an encrypted viewing-key mechanism for regulatory compliance. Broader DeFi features, cross-chain access, and public usage data have not yet been released. The rollout places Starknet among several networks currently offering transaction-level privacy features.