In addition to working with our amazing clients, ScopeLift regularly builds publics goods, open source projects. These projects provide an opportunity to experiment with new tooling and processes, then bring those learnings back to our clients. It’s also simply an opportunity for us to build cool stuff we see as missing in the ecosystem! Here’s a brief look at a few our our publics good projects

Umbra: Privacy Preserving Payments for the EVM

Umbra logoUmbra is an open source protocol for stealth payments on EVM blockchain networks. It enables privacy preserving transactions where the receiver's identity is only known to the sender and receiver.

One way to think of Umbra is this: before anyone sent you funds, you sent them a brand new, never before used address. Only the sender would know you control that address, which adds a layer of privacy to your payment. Payments via Umbra work similarly, but are non-interactive—you don’t need to give someone a fresh address, the sender can just generate one they know only you will be able to access.

Umbra diagram

ScopeLift shipped a barebones version of Umbra for the ETHGlobal hackathon where it qualified as a finalist and won several prizes. After ETHGlobal, ScopeLift received several grants— including one from the Ethereum Foundation— to build a production-worthy version of Umbra.

In early 2021, a fully audited Umbra shipped to the Ethereum Mainnet. Since then, we’ve continued to build out Umbra’s features and functionality. Umbra is now live on five networks (Ethereum, Polygon, Optimism, Arbitrum, and Gnosis Chain) where it has processed over 250,000 transactions, representing $450+ million in value.

Stealth Address Standardization

To our knowledge, this makes Umbra the most widely used implementation of stealth addresses on Ethereum, the EVM, or any cryptonetwork, period. ScopeLift is incredibly proud to have led the way in making stealth addresses more accessible and useable.

With that said, we also realize there is much more that needs to be done before stealth addresses, and all privacy tools, reach their full potential in the crypto ecosystem. That’s why we’re excited to announce that ScopeLift has received a grant from the Ethereum Foundation to help push stealth addresses forward on the EVM.

Stealth Bomber Flies Past The Moon

To that end, ScopeLift is working with other developers and researchers in the ecosystem to advance two ERCs to standardize stealth addresses on the EVM. They are:

  • ERC-5564 — Stealth Addresses: Private, non-interactive transfers and interactions
  • ERC-6538 — Stealth Meta-Address Registry: A registry to map addresses to stealth meta-addresses

Together, these two ERCs create a lightweight, flexible and powerful set of tools to allow developers to adopt stealth addresses. The ERCs are designed to be interoperable and completely permissionless.

We believe this point is absolutely crucial. To truly gain traction, we believe a stealth address protocol needs to be a public good—one that can be permissionlessly integrated into dapps, wallets, and other protocols; and one that can’t be turned off or censored by any organization or authority.

Read More about our stealth address standardization efforts.

Flexible Voting: Expanding

Flexible Voting is an extension to the widely used OpenZeppelin Governor that enables novel voting schemes to be created.

For a DAO that adopts it, the Flexible Voting extension allows delegates to split their voting weight across For/Against/Abstain options for a given proposal. This new building block allows arbitrary delegate contracts to be developed which can unlock all kinds of new use cases, such as voting with tokens while earning yield in DeFi, voting with tokens bridged to L2, shielded privacy preserving voting, and much more.

Stealth Bomber Flies Past The Moon

Flexible Voting is open source and available for new and existing DAOs to adopt. It’s already in use by DAOs like Gitcoin, Frax Finance, and PoolTogether. Several other large DAOs are in the process of adopting it, and we’re actively building out usecases on top of it, such as crosschain voting powered by Wormhole

Visit to learn more about this powerful DAO governance primitive.