Glossary
Short definitions of every term used in these docs.
Announcement. The public event a sender emits through the ERC-5564 Announcer for each payment: the stealth address, the sender's ephemeral public key and metadata.
Announcer. The ERC-5564 singleton contract that emits announcements, at 0x55649E01B5Df198D18D95b5cc5051630cfD45564 on Ethereum, Arbitrum, Base, Optimism and Polygon.
CCIP-Read (EIP-3668). The ENS mechanism that lets a name resolve through an offchain gateway. Private names use it to return a fresh address on every lookup.
Collector pattern (H3). Several stealth addresses withdrawn to the same address, which groups them under one owner.
Ephemeral key. The one-time key pair a sender creates for a single payment. Its public half is published in the announcement.
ERC-5564. The Ethereum standard for stealth addresses. ephemeral uses scheme 1: secp256k1 with view tags.
ERC-6538. The standard registry where an address can publish its stealth meta-address, at 0x6538E6bf4B0eBd30A8Ea093027Ac2422ce5d6538.
Fee fingerprint (H4). A rarely used priority fee that repeats across withdrawals and groups them.
Gas funding (H5). Funding a token-only stealth address with ETH from a wallet linked to its owner.
Leak. Any action that links a stealth address back to its owner.
Meta-address. Your two public keys, spending and viewing, shared once as st:eth:0x…. Senders derive stealth addresses from it.
Private name. A name such as name.ephmrl.eth that resolves to a fresh stealth address on every lookup.
Privacy set. The group of people a payment could plausibly belong to.
Registrant reuse (H1). Withdrawing to the address that registered your stealth keys. The most common leak that names the owner.
Round trip (H2). Sending funds back to the address that paid you.
Shared secret. The point that the sender computes from their ephemeral key and your viewing key, and that you compute from your viewing key and their ephemeral public key.
Spending key. The private key needed to move funds out of your stealth addresses. Never share it.
Stealth address. An ordinary Ethereum address used for exactly one payment, derived so that only its owner can find it and spend from it.
View tag. The first byte of the hashed shared secret. It lets a receiver discard 255 of 256 announcements that are not theirs.
Viewing key. The private key that finds payments to you and shows their amounts. It cannot move funds.
Withdrawal policy engine. The part of the client that checks every outgoing move against H1 to H5 and blocks or warns.