Shielding is how you break the on-chain link between “where funds came from” and “where they go later.”
Default path in this guide: receive on a fresh address → shield into Tornado → leave funds private for a while.
# Dry run first
Omit --broadcast to see the planned transaction without sending it:
kohaku shield --protocol tornado --amount-formatted 1.0
Interactive mode lets you pick the public account that holds the funds. When it looks right, add --broadcast:
kohaku shield --protocol tornado --amount-formatted 1.0 --broadcast
You can also shield from an address outside this wallet. Select it with --from 0xYourAddress; on an interactive broadcast, the CLI asks for its private key with hidden input. For a non-interactive broadcast, pass --sender-priv <key> as well. The key must match --from and is not saved. An unsaved HD index from this wallet’s seed needs no separate key; the CLI derives it automatically. Dry runs do not need the sender key.
Prefer the hidden interactive prompt when possible: putting a key directly on a command line can expose it through shell history or process listings.
kohaku shield --protocol tornado --from 0xYourAddress --amount-formatted 0.1 --broadcast
For ERC20s, pass the token:
kohaku shield --protocol tornado --token USDC --amount-formatted 1000 --broadcast
kohaku shield --protocol tornado --token DAI --amount-formatted 1000 --broadcast
For now these are the only relevant tokens with tornado pools, hopefully more tokens and amounts get bootstrapped and we’ll add them to the CLI.
Privacy Pools accepts any amount at or above the pool minimum (mainnet: ETH, USDC, USDT) — useful for dust that does not fit a Tornado note. For an arbitrary ERC-20 with no Tornado / Privacy Pools pool, Railgun can shield it:
kohaku shield --protocol railgun --token 0xYourToken --amount-formatted 10 --broadcast
# Inspect a shield without the tokens
A normal dry-run simulates the transaction, so it fails if the sender does not hold the funds yet. Pass --skip-sim to still print the planned payloads — useful when you want the call data for a later unshield --tail-calls, or to inspect a shield from an address that is not funded yet:
kohaku shield --from 1 --amount-formatted 0.1 --skip-sim
--skip-sim is dry-run only (cannot be combined with --broadcast). Fees in --non-interactive JSON stay in the schema but are zeroed.
# Note sizes
Tornado uses fixed denomination notes. ETH pools include 0.01, 0.03, 0.1, 0.3, 1, 3, 10, and 30 ETH sizes (10 ETH is also available on Sepolia). You can shield amounts such as 0.01 or 0.45 ETH by combining notes. The amount must be an exact multiple of 0.01 ETH. Pass --exclude-new-pools to use only classic pools; then the minimum step is 0.1 ETH.
The new denominations may have much smaller anonymity sets than the classic pools. Check the pool selection in the shield preview before broadcasting. A smaller note is not automatically a more private note.
Interactive shields offer note packings and show the denominations, note count, and transaction count. Repeat --exclude-denomination <amount> to avoid a specific pool size; for example, --exclude-denomination 0.03. The confirmation shows a breakdown by denomination and the estimated fees, without listing pool contract addresses.
The CLI puts at most five deposit notes per transaction (approval calls do not count). Larger shields split into sequential transactions by default. If a later transaction fails, earlier deposits may already be shielded; check the reported hashes and amounts before retrying. Use --disallow-multiple-userops to reject a plan that needs more than one transaction.
After a successful Tornado shield, the CLI prints an Etherscan link for each transaction and ✔ Shield flow completed. Sepolia transactions link to Sepolia Etherscan.
New Tornado and Privacy Pools deposits use signature-derived note secrets. Older notes remain in your wallet and can still be spent.
Before preparing new Tornado or Privacy Pools notes, the CLI refreshes complete protocol history and checks note indexes across pools and assets, including spent deposits. Tornado notes in one shield plan get distinct nonces even when they use different denominations or transactions. If that history cannot be verified through the sampled chain head, preparation stops. A pending external deposit can still race with a separately prepared shield.
Shield as much as fits into valid notes from the fresh address. Leave leftovers alone for now — see Dust Management.
# After shielding
kohaku balances
Public balance on that address should drop; Tornado private balance should rise.
# Let it sit
Do not unshield immediately. The privacy of a withdrawal depends partly on other people depositing and withdrawing around the same time. Leaving funds shielded for a meaningful period is part of the point.
When you eventually need public funds again, go to Unshield Funds.