How privacy works

Murk's privacy comes from a Zcash-style shielded pool: commitments, nullifiers, and zero-knowledge proofs. Here's the intuition, without the math.

Notes and commitments

Your private funds are notes: (token, amount, owner, randomness). Only a commitment — a hash of the note — goes on-chain, as a leaf in a Merkle tree. The commitment hides the amount, the token, and the owner, but binds them: you can't later claim a different amount.

The note's contents are also encrypted and posted on-chain so only you (with your viewing key) can find and read them.

Spending: nullifiers

To spend a note you prove, in zero-knowledge, that:

• you know the secret behind the note's owner key,
• the note's commitment is really in the tree, and
• the inputs and outputs balance (no value created).

Spending reveals a one-time nullifier — derived from your secret and the note's position — which is recorded so the note can't be spent twice. Crucially, the nullifier is unlinkable to the commitment: no observer can tell which note was spent.

The anonymity set

Your privacy is as strong as the crowd you hide in. When you spend, your proof says "one of the notes in the tree" — the bigger and more active the pool, the harder it is to guess which. A brand-new pool with few users offers weaker privacy than a large, busy one.

What leaks (and how to reduce it)

Privacy is probabilistic and depends on your habits:

• Deposits and withdrawals are public. Depositing 10 SOL then withdrawing 10 SOL soon after, to a linked address, is easy to correlate. Vary amounts, wait, and use fresh addresses.
• Timing. A relayer or network observer sees when you act and coarse metadata (the kind of action, the fee). Use a relayer + a VPN/private RPC to reduce this.
• Off-chain reuse. Reusing addresses or revealing note details elsewhere undoes on-chain privacy.

What never leaks

Given the above, on-chain: amounts, mints, senders, recipients, and balances of shielded transfers stay hidden, verified by the proof — not trusted to any operator.

Learn about the keys involved next: Your keys, explained.