Category: stealth-address standard / recipient-privacy infrastructure / announcement-and-scanning primitive
Summary: ERC-5564 is best understood as a spec-level baseline for recipient privacy on EVM chains rather than as a finished wallet or privacy product. Its core move is to standardize the vocabulary and interfaces around stealth meta-addresses, viewing-versus-spending keys, stealth-address generation, recipient-side scanning, and singleton announcement emission. That makes it analytically useful because it turns “stealth addresses” from a loose design pattern into a comparison-ready control plane with explicit choices about who publishes keys, who scans announcements, how recipients derive spend authority, and how much metadata gets revealed for usability.
What it does:
Standardizes interfaces for generating a stealth address, checking whether an announced stealth address belongs to a recipient, and deriving the stealth private key
Defines stealth meta-addresses built from one or two public keys and distinguishes viewing keys from spending keys
Introduces schemeId-based extensibility and specifies an initial SECP256k1-with-view-tags implementation as scheme 1
Defines a singleton ERC5564Announcer contract that emits Announcement events containing the scheme, stealth address, caller, ephemeral public key, and metadata
Standardizes a st:<chain>:0x... stealth meta-address format and explicitly points to ERC-6538 as the registry layer for publishing those meta-addresses
Uses one-byte view tags to let recipients skip most heavy parsing work for almost all announcements that are not for them
Key claims:
The final ERC frames stealth addresses as private, non-interactive transactions and says the standard lets senders generate recipient-only private accounts without prior coordination. That is the clearest reason to catalog it as recipient-privacy infrastructure rather than as a niche wallet feature.
The spec’s most important decomposition is between spending authority and viewing authority. That split makes third-party scanning, notification, and indexing services legible without giving those services spend power.
The singleton announcer contract is a major architectural choice, because it turns stealth transfers into a common event surface that wallets, indexers, and SDKs can monitor. In other words, discoverability and scanning become part of the standard’s practical control plane.
View tags are not a cosmetic optimization; the ERC says they reduce parsing work by around 6x and let users skip the expensive remaining computations for roughly 255 out of 256 unrelated announcements. That makes usability and scanning cost a first-class design consideration.
The rationale and parsing sections also make the tradeoff explicit: view tags leak one byte of the shared secret, slightly reducing privacy margin in exchange for a large improvement in scanning efficiency.
ERC-6538 is an important adjacent source in this pass because ERC-5564 alone standardizes the stealth-address mechanics, while ERC-6538 standardizes where a user’s stealth meta-address can be registered and discovered by other contracts or users.
ScopeLift’s stealth-address SDK is useful evidence that the standard is not purely theoretical: the ecosystem is already treating ERC-5564 and ERC-6538 as practical integration layers for announcement fetching, scanning, subgraph pagination, and live watch flows.
ERC-5564 is a strong comparison class for Umbra and other stealth-address systems because it exposes the lower-layer primitive itself: meta-address publication, announcement transport, scanning economics, and key-derivation logic.
Whitepaper: No standalone ERC-5564 whitepaper or litepaper surfaced in this pass. The clearest primary materials were the final ERC text, the raw ERC markdown, the reference announcer contract, the related ERC-6538 registry standard, and the ScopeLift stealth-address SDK README collected in ../../whitepapers/erc-5564-primary-sources-2026-05-11.md.