Umbra: Privacy-Preserving Stealth Payments On Ethereum
Umbra is a protocol for enabling stealth payments on the Ethereum blockchain. It enables privacy preserving transactions where the receiver’s identity is only known to the sender and receiver.
Make Payments Without Revealing Your Relationship
Umbra is meant for payments between two entities, and comes with a different set of privacy tradeoffs than mixer solutions. Rather than breaking the link between sending and receiving address, Umbra makes that link meaningless. Everyone knows the address funds were sent to, but they don’t know who controls that address.
This means Umbra…
- Allows arbitrary amounts to be sent, since there is no need for inputs and outputs to be uniform
- Does not require the receiver to wait to withdraw funds
- Ensures only the receiver can withdraw the funds once they’re sent
- Uses significantly less gas
- Enables ETH and arbitrary ERC20 tokens to be transferred privately without first requiring an anonymity set developing
A proof of concept MVP was built for the HackMoney hackathon. It was among the Hackathon’s finalists and won prizes from ENS and OpenGSN. You can watch our submission demo.
You can also try it out on Ropsten at https://ropsten.umbra.cash.
Our goal is to get to mainnet in Fall 2020. To do so, we’ll:
- Write a formal protocol specification and write an ERC to take feedback from the community
- Implement planned improvements to the protocol and integrate community feedback
- Acquire security audits from two reputable firms and implement any recommendations made
- Launch to mainnet, build useful tools on top of Umbra, and help other developers do the same
$3,000 in DAI to pay for Consensys Dilligence’s one day security review program.
The Consensys Diligence team offers a 12 hour security review for $3,000. While this is not a full audit by any stretch, it can help surface large architectural issues early, and provide direction for avoiding pitfalls now that would be more costly to address later. Additionally, Diligence will deduct the $3,000 cost of this review from the cost of a full security audit, so this will also help make the full security audit more affordable.
This audit also plays into MetaCartel’s ongoing relationship with the Consensys Diligence team.
- Matt Solomon (@msolomon44) – Former Aerospace Engineer with 5+ years of professional software development experience. Co-Founder of Floatify. (https://floatify.net/). Software Engineer at ScopeLift.
- Ben DiFrancesco (@BenDiFrancesco) – Former Aerospace Engineer with 15+ years of professional software development experience. Founder of ScopeLift (https://www.scopelift.co/). Author of Build Blockchain newsletter (https://www.buildblockchain.tech/newsletter). Blockchain obsessed since 2012.
For more information, and to see our code, checkout the GitHub repository at https://github.com/ScopeLift/umbra-protocol
How Does This Benefit MetaCartel?
As ecosystem actors frequently working and collecting payment in crypto, we feel that Umbra is a perfect solution for anyone who wants to continue receiving ETH, DAI, etc. without having to reveal their identity - something which also allows anyone to backtrack and reverse engineer where different payments came from (and who you worked with).
While there are convoluted ways of working around this, we believe Umbra is a much more intuitive solution.
In exchange for this grant we’d like to invite members of MetaCartel to partner with us for our soft launch - being amongst the first to access and use the product before it is announced to the public.