Frontend Withdraw

Frontend Withdraw on Base

withdraw()

withdraw() is a function from privacycash-evm used to withdraw ETH from the Privacy Cash protocol to a specified recipient address on Base.

Parameters

Parameter	Type	Description
withdrawAmountInput	number	Total amount of ETH to withdraw. Fees are deducted from this value.
recipient	string	The Base address that will receive the withdrawn funds.
keyBasePath	string	Base path for the circuit zkey (e.g. '/circuit').
signature	string	Wallet signature of the Privacy Cash sign-in message.
address	string	The withdrawer’s EVM wallet address.

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Example Usage

'use client'
import { withdraw } from 'privacycash-evm'
import { useAccount } from 'wagmi'

export function WithdrawButton() {
    const { address } = useAccount()

    const handleWithdraw = async () => {
        if (!address) return

        const signature = localStorage.getItem(`evm_sign_${address}`)
        if (!signature) {
            alert('Please sign in first.')
            return
        }

        const recipient = '0xRECIPIENT_ADDRESS'

        const txHash = await withdraw({
            withdrawAmountInput: 0.05,  // Total including fees
            recipient,
            keyBasePath: '/circuit',
            signature,
            address,
        })

        console.log('Withdraw tx:', txHash)
    }

    return <button onClick={handleWithdraw}>Withdraw 0.05 ETH</button>
}

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Fee Estimation

To display the estimated received amount before the user submits:

import { RENT_FEE, FEE_RATE } from 'privacycash-evm'

function estimateReceived(withdrawAmount: number): number {
    const flatFee = RENT_FEE                          // 0.00025 ETH
    const rateFee = (withdrawAmount * FEE_RATE) / 10000 // 0.35%
    return withdrawAmount - flatFee - rateFee
}

console.log(estimateReceived(0.1))  // ~0.09940 ETH

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Notes

• withdrawAmountInput is the total amount deducted from your private balance; the recipient receives less after fees.
• Always validate that withdrawAmountInput <= privateBalance before calling withdraw().
• The recipient must be a valid EVM address (0x + 40 hex characters).