Deposit

Deposit ETH into Privacy Cash on Base

Deposit ETH

Deposit ETH into the Privacy Cash privacy pool on Base.

import { deposit } from 'privacycash-evm'

const tx = await deposit({
  depositAmountInput: number,
  keyBasePath: string,
  signature: string,
  address: string,
  txSender: (unsignedTx: any) => Promise<string>
})

Parameters

Parameter	Type	Required	Description
depositAmountInput	number	Yes	Amount to deposit in ETH (e.g. 0.1 for 0.1 ETH)
keyBasePath	string	Yes	Base path to the circuit zkey file (without extension)
signature	string	Yes	Wallet signature of the Privacy Cash sign-in message
address	string	Yes	The depositor’s EVM wallet address
txSender	Function	Yes	Callback that signs and submits the raw transaction, returns tx hash

Returns

The transaction hash (string).

Example

import { ethers } from 'ethers'
import { deposit, SIGN_PRIVACY_MESSAGE } from 'privacycash-evm'

const provider = new ethers.providers.JsonRpcProvider(process.env.BASE_RPC_URL!, {
  name: 'base',
  chainId: 8453,
})
const signer = new ethers.Wallet(process.env.PRIVATE_KEY!, provider)

const signature = await signer.signMessage(SIGN_PRIVACY_MESSAGE)
const address = await signer.getAddress()

const txSender = async (unsignedTx: any) => {
  const tx = await signer.sendTransaction(unsignedTx)
  await tx.wait()
  return tx.hash
}

const txHash = await deposit({
  depositAmountInput: 0.01, // 0.01 ETH
  keyBasePath: './circuits/transaction',
  signature,
  address,
  txSender,
})

console.log('Deposit tx:', txHash)

Deposit Limits

The protocol enforces a maximum deposit amount. Attempting to exceed it will throw:

Please deposit less than X ETH

There is also a minimum deposit amount of 0.001 ETH.

Depositing below the minimum will throw Deposit amount must be at least 0.001 ETH.

Fees

Fee Type	Amount
Protocol fee	Free (0)
Network fee	~0.0001 ETH (Base transaction fee)

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How Deposits Work

1. ZK Proof Generated

   The SDK derives your keypair from the signature, scans on-chain UTXOs, and generates a ZK proof consolidating any existing UTXOs with the new deposit amount.

2. Address Screening

   Your wallet address is screened for malicious activity before the transaction is built.

3. Transaction Built

   An unsigned transaction is created and passed to your txSender callback for signing and submission.

4. UTXO Created

   An encrypted UTXO is written on-chain, decryptable only by you.

Consolidation

New deposits are automatically consolidated with your existing private balance:

// First deposit: 0.05 ETH
await deposit({ depositAmountInput: 0.05, ... })

// Second deposit: 0.03 ETH — merged into a single UTXO
await deposit({ depositAmountInput: 0.03, ... })
// Private balance is now 0.08 ETH (minus network fees)