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Sample Project

https://github.com/Privacy-Cash/privacy-cash-evm-sdk/blob/main/example/

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Installation

npm install privacycash-evm --save
Requires Node.js 20+. The SDK is written in TypeScript and includes type definitions.

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Signing In

The SDK uses a wallet signature to derive your private encryption key and UTXO keypair. Ask the user to sign a fixed message: 
import { ethers } from 'ethers'
import { SIGN_PRIVACY_MESSAGE } from 'privacycash-evm'

const provider = new ethers.providers.JsonRpcProvider('YOUR_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()
The resulting signature and address strings are passed directly to each SDK function. No separate initialization step is required.

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Sending Transactions

deposit() requires a txSender callback that signs and submits the raw transaction: 
const txSender = async (unsignedTx: any) => {
  const tx = await signer.sendTransaction(unsignedTx)
  await tx.wait()
  return tx.hash
}

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Interacting with Privacy Cash

Once the above steps are done, you can check balance, make deposits and withdrawals.

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Supported Network

Privacy Cash on Base operates on Base Mainnet (chain ID 8453). There is no testnet deployment. 
import { deposit, withdraw, getBalance } from 'privacycash-evm'

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Key Path

All functions accept a keyBasePath parameter pointing to the circuit zkey file (without extension): 
keyBasePath: './circuits/transaction'  // loads ./circuits/transaction2.zkey
For Next.js projects, place the .zkey file in the public/ folder: 
keyBasePath: '/circuit'  // loads /circuit2.zkey from public/