Proposal for Stealth Addresses: ERC-5564 and ERC-6538

Proposal for Stealth Addresses: ERC-5564 and ERC-6538.

Stealth Addresses are a privacy-enhancing payment tool where only the sender and receiver know who the receiver is. UmbraCash is one of the projects in this field, and to expand adoption, the project developer Matt Solomon standardized stealth addresses into two proposals: ERC-5564 and ERC-6538. This article is his interpretation of the proposals.

In order to improve adoption and flexibility, we hope to standardize the way stealth addresses work. ERC-5564 is a minimal, flexible, and standardized proposal that defines a method for representing stealth element addresses, spending and viewing keys, and an initial implementation using the secp256k1 curve. It also standardizes the following interfaces: generating a stealth address from a stealth element address (SMA), checking if funds have been received, calculating the private key of a stealth address, and announcing that a user has sent funds.

ERC-5564 does not explicitly standardize the following: a single method for calculating a stealth address, a single elliptic curve or stealth protocol that must be used, and a method for reducing the time it takes to check if a user has funds. This allows users to choose their own user experience and security attributes.

ERC-6538 defines a smart contract where users can register their stealth element address for senders. Some users may prefer to privately share their stealth element address (SMA), so we have extended this proposal.