Privacy Cash explained: how the Solana privacy pool works

How it works

1. Deposit. You send SOL (or USDC, USDT and a few other coins) into the pool. The pool records a commitment, a fingerprint of a secret only your device knows.
2. Wait. Your deposit sits in the pool with everyone else’s. Nothing about it is tied to where it will go.
3. Withdraw. Your device builds a zero-knowledge proof that says “I own one of the deposits in this pool, and it has not been spent”, without saying which one. A relayer sends the withdrawal and pays its network fee, so the receiving wallet does not need any SOL first.

On chain, the deposit goes in from your wallet and the withdrawal comes out to another, and no transaction connects the two. Privacy Cash’s program cannot be made to pay a withdrawal twice: each deposit has a nullifier that is marked spent when it is used.

What it costs

From Privacy Cash’s live settings on 27 October 2026. Other coins have their own minimums and flat fees; for USDC the flat part is about 0.60 USDC.

For a 2 SOL withdrawal that is 0.007 + 0.006 = 0.013 SOL, so 1.987 SOL lands.

What it hides and what it does not

Privacy Cash breaks the link between the deposit and the withdrawal. It does not make either one invisible:

• Amounts are public. Everyone can see 2 SOL go in and 1.987 SOL come out. If you are the only one who deposited 2 SOL today, the match is easy.
• Times are public. A withdrawal a minute after a deposit narrows it down. The longer you wait, the more other deposits yours is mixed with.
• Your IP address is not protected. The service that relays your withdrawal can see the connection.
• A small pool hides less. Privacy grows with how many people use it.

So the habits matter: wait, do not withdraw the exact amount you put in, and do not send the result straight back to your main wallet.

Is it custodial?

No company holds your SOL while it is in the pool. The secret that proves a deposit is yours is worked out from a signature by the wallet that paid in, so that wallet’s key is also the key to the deposit. Keep it backed up until the money has landed.

How Raven uses it

Privacy Cash is one of Raven’s three private routes. Send privately, pick Privacy Cash, and choose when it lands: right away or after a wait you set. Raven tracks every deposit until it lands, retries if a withdrawal fails, and lets you land it now or change where it goes. The relayer checks each receiving address and refuses ones it considers risky; Raven shows that refusal and lets you pick another address.

Questions

Is Privacy Cash a mixer?

It is a privacy pool: your SOL goes into a shared pool and comes out unlinked, using zero-knowledge proofs rather than a company that shuffles funds. Rules on privacy pools differ by country, so know yours.

How long should I wait before withdrawing?

Longer is more private. A wait of hours rather than minutes, with an amount that does not match your deposit, makes the link far harder to guess.

Can Privacy Cash take my money?

The pool is a program on Solana, and withdrawals need your proof. The risk is in the program’s code, which its documentation says has been audited, and in losing the key of the wallet that paid in before the money lands.

Sources

• Privacy Cash documentation
• Privacy Cash: how it works
• Privacy Cash: privacy model
• Privacy Cash: best practices