> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/Privacy-Cash/privacy-cash/llms.txt
> Use this file to discover all available pages before exploring further.

# Installation

> Install and configure the Privacy Cash SDK

## Prerequisites

Before installing the SDK, ensure you have the following:

<CardGroup cols={2}>
  <Card title="Node.js" icon="node-js">
    Version 16 or later
  </Card>

  <Card title="Solana CLI" icon="terminal">
    Version 2.1.18 or later
  </Card>

  <Card title="Anchor" icon="anchor">
    Version 0.31.1 (for development)
  </Card>

  <Card title="TypeScript" icon="code">
    Recommended for type safety
  </Card>
</CardGroup>

## Install the SDK

The Privacy Cash SDK is available on GitHub. Install it using npm or yarn:

<CodeGroup>
  ```bash npm theme={null}
  npm install @privacy-cash/sdk
  ```

  ```bash yarn theme={null}
  yarn add @privacy-cash/sdk
  ```

  ```bash pnpm theme={null}
  pnpm add @privacy-cash/sdk
  ```
</CodeGroup>

<Note>
  The SDK package is hosted at [github.com/Privacy-Cash/privacy-cash-sdk](https://github.com/Privacy-Cash/privacy-cash-sdk).
</Note>

## Install Dependencies

The SDK requires several peer dependencies for cryptographic operations:

<CodeGroup>
  ```bash npm theme={null}
  npm install @coral-xyz/anchor @solana/web3.js @solana/spl-token \
    @lightprotocol/hasher.rs snarkjs ffjavascript bn.js borsh \
    @ethersproject/sha2
  ```

  ```bash yarn theme={null}
  yarn add @coral-xyz/anchor @solana/web3.js @solana/spl-token \
    @lightprotocol/hasher.rs snarkjs ffjavascript bn.js borsh \
    @ethersproject/sha2
  ```
</CodeGroup>

### Dependency Overview

| Package                    | Purpose                              |
| -------------------------- | ------------------------------------ |
| `@coral-xyz/anchor`        | Solana program interaction framework |
| `@solana/web3.js`          | Solana blockchain interaction        |
| `@solana/spl-token`        | SPL token operations                 |
| `@lightprotocol/hasher.rs` | Poseidon hash implementation (WASM)  |
| `snarkjs`                  | Zero-knowledge proof generation      |
| `ffjavascript`             | Finite field arithmetic              |
| `bn.js`                    | Big number operations                |
| `borsh`                    | Binary serialization                 |
| `@ethersproject/sha2`      | SHA-256 hashing                      |

## Download Circuit Files

The SDK requires circuit files for proof generation. These are large files (100MB+) and must be downloaded separately:

<Steps>
  <Step title="Clone the Repository">
    ```bash theme={null}
    git clone https://github.com/Privacy-Cash/privacy-cash
    cd privacy-cash
    ```
  </Step>

  <Step title="Build Circuit Artifacts">
    ```bash theme={null}
    cd anchor/circuits
    # Install circom if not already installed
    # See: https://docs.circom.io/getting-started/installation/

    # Compile the circuit
    circom transaction2.circom --r1cs --wasm --sym

    # Generate proving and verification keys
    # This requires a trusted setup ceremony (powers of tau)
    snarkjs groth16 setup transaction2.r1cs pot_final.ptau transaction2.zkey
    ```
  </Step>

  <Step title="Copy Artifacts to Your Project">
    ```bash theme={null}
    mkdir -p your-project/circuits
    cp artifacts/circuits/transaction2/transaction2.wasm your-project/circuits/
    cp artifacts/circuits/transaction2/transaction2.zkey your-project/circuits/
    ```
  </Step>
</Steps>

<Warning>
  Circuit files are typically 100-500MB in size. Ensure you have sufficient disk space and bandwidth.
</Warning>

## Initialize the SDK

Create a configuration file to initialize the SDK:

```typescript config.ts theme={null}
import { Connection, PublicKey } from '@solana/web3.js';
import { AnchorProvider, Program } from '@coral-xyz/anchor';
import { WasmFactory } from '@lightprotocol/hasher.rs';

// Initialize connection
const connection = new Connection('https://api.mainnet-beta.solana.com', 'confirmed');

// Initialize Poseidon hasher
const lightWasm = await WasmFactory.getInstance();

// Program ID
const PROGRAM_ID = new PublicKey('9fhQBbumKEFuXtMBDw8AaQyAjCorLGJQiS3skWZdQyQD');

// Circuit paths
const CIRCUIT_WASM = './circuits/transaction2.wasm';
const CIRCUIT_ZKEY = './circuits/transaction2.zkey';

export { connection, lightWasm, PROGRAM_ID, CIRCUIT_WASM, CIRCUIT_ZKEY };
```

## Verify Installation

Test your installation with a simple script:

```typescript test-installation.ts theme={null}
import { WasmFactory } from '@lightprotocol/hasher.rs';
import { Utxo } from '@privacy-cash/sdk';
import BN from 'bn.js';

async function testInstallation() {
  // Initialize hasher
  const lightWasm = await WasmFactory.getInstance();
  
  // Create a test UTXO
  const utxo = new Utxo({
    lightWasm,
    amount: new BN(1000000), // 0.001 SOL
  });
  
  // Generate commitment
  const commitment = await utxo.getCommitment();
  console.log('UTXO commitment:', commitment);
  
  // Generate nullifier
  const nullifier = await utxo.getNullifier();
  console.log('UTXO nullifier:', nullifier);
  
  console.log('✅ Installation verified successfully!');
}

testInstallation().catch(console.error);
```

Run the test:

```bash theme={null}
ts-node test-installation.ts
```

<Check>
  If you see commitment and nullifier outputs, your installation is complete!
</Check>

## Environment Configuration

Create a `.env` file for sensitive configuration:

```bash .env theme={null}
# Network Configuration
SOLANA_RPC_URL=https://api.mainnet-beta.solana.com
CLUSTER=mainnet-beta

# Program ID
PROGRAM_ID=9fhQBbumKEFuXtMBDw8AaQyAjCorLGJQiS3skWZdQyQD

# Circuit Files
CIRCUIT_WASM_PATH=./circuits/transaction2.wasm
CIRCUIT_ZKEY_PATH=./circuits/transaction2.zkey

# Fee Configuration
FEE_RECIPIENT=AWexibGxNFKTa1b5R5MN4PJr9HWnWRwf8EW9g8cLx3dM
```

<Warning>
  Never commit private keys or seed phrases to version control. Use environment variables or secure key management systems.
</Warning>

## TypeScript Configuration

Add proper TypeScript configuration for the SDK:

```json tsconfig.json theme={null}
{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "lib": ["ES2020"],
    "moduleResolution": "node",
    "esModuleInterop": true,
    "skipLibCheck": true,
    "strict": true,
    "resolveJsonModule": true,
    "outDir": "./dist",
    "rootDir": "./src"
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Basic Usage" icon="code" href="/sdk/basic-usage">
    Learn core SDK operations
  </Card>

  <Card title="Examples" icon="book" href="/sdk/examples">
    View complete integration examples
  </Card>
</CardGroup>