Your keys, explained

Murk uses a small set of keys, all derived from your wallet. You never manage a separate seed phrase.

Spend key

The master secret. It's derived on your device from a signature your wallet makes over a fixed message (not a transaction). From it, everything else follows. The spend key:

• opens your notes' owner key (ownerKey = hash(spendKey)) — proving you own a note,
• produces nullifiers when you spend — authorizing exactly one spend per note.

It is held in memory only, never stored or transmitted. Re-derive it anytime by connecting the same wallet and signing again.

Viewing key

A one-way subkey of the spend key (viewSeed = hash(spendKey, …)). It can decrypt your notes — read amounts and history — but cannot spend. Because it's a one-way hash of the spend key, having the viewing key never reveals the spend key.

This split is what enables compliance viewing keys: you can hand someone read access without handing over control.

Receive (shielded) address

Your public owner key + viewing public key, packed together. Others encrypt notes to it when they pay you. You can register it on-chain once so people can send to you by your ordinary Solana pubkey.

How they relate

wallet signature ──► spend key ──► owner key + nullifiers   (SPEND)
                          │
                          └──► viewSeed ──► viewing key       (READ ONLY)

• Spend key → can read and spend. Keep it secret.
• Viewing key → can read only. Safe to share with an auditor.
• Receive address → fully public. Share freely so people can pay you.

Losing / recovering

There's nothing extra to back up: your Murk keys are a function of your Solana wallet. Keep your wallet safe, and you keep your Murk funds. Lose your wallet, and — as with any self-custody — the funds are gone.