What we promise. And what we don’t.

Caution · withdrawal

How withdrawal works — and where its privacy ends.

A withdrawal is two transactions, neither of which is a direct vault-to-wallet transfer. The vault signs a step that creates a UTXO whose destination is AES-encrypted on-chain. The Umbra relayer then signs a separate transaction that credits the destination wallet’s public balance. An on-chain observer can’t draw a line between the two without solving for the mixer’s anonymity set.

• Anonymity set. The mixer only mixes you with other Umbra users withdrawing in the same window. The create leg is timing-only — the amount stays inside the encrypted balance — but the claim leg has both timing and a public amount. On devnet today and on low-volume mainnet, that anonymity set is small, so an observer can still pair a recent vault-side create event with a public claim by timing alone, plus the claim’s amount as a tiebreaker. Privacy here grows with the network, not with any single transaction.
• The destination is public. Once funds land in a public wallet, the credit transaction — amount and timing — is visible on that wallet’s history. Withdraw to an address already known to be yours, or move unique amounts on a predictable schedule, and observers can guess which mixer exit was yours.
• Server-side trust. The handle-to-vault mapping lives in the Monyr database, and encrypted receipt metadata is stored server-side. The mixer doesn’t protect against a Monyr-server adversary or a subpoena — for that, the defenses are the encrypted-vault model and the absence of unencrypted memos.

Practical pattern: keep funds inside the vault and spend through Umbra-aware flows where possible. Withdraw only when you must move to fiat or to a wallet outside Monyr — and prefer a destination that doesn’t already have a public history tied to you.