> ## 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.

# initialize

> Initialize the Privacy Cash program with SOL merkle tree and global configuration

## Overview

The `initialize` instruction sets up the Privacy Cash program for the first time. It creates the main merkle tree for SOL transactions, initializes the tree token account, and establishes global fee configuration.

<Note>
  This instruction can only be called once per program deployment and requires admin authorization on mainnet.
</Note>

## Function Signature

```rust theme={null}
pub fn initialize(ctx: Context<Initialize>) -> Result<()>
```

## Accounts

<ParamField path="tree_account" type="AccountLoader<MerkleTreeAccount>" required>
  The main merkle tree account for SOL transactions. PDA derived from `["merkle_tree"]`.

  * **Mutable**: Yes
  * **Initialized**: Yes (created by this instruction)
</ParamField>

<ParamField path="tree_token_account" type="Account<TreeTokenAccount>" required>
  Account that holds deposited SOL tokens. PDA derived from `["tree_token"]`.

  * **Mutable**: Yes
  * **Initialized**: Yes (created by this instruction)
</ParamField>

<ParamField path="global_config" type="Account<GlobalConfig>" required>
  Global configuration account containing fee rates. PDA derived from `["global_config"]`.

  * **Mutable**: Yes
  * **Initialized**: Yes (created by this instruction)
</ParamField>

<ParamField path="authority" type="Signer" required>
  The authority that can initialize the program. Must match the admin pubkey on mainnet.

  * **Mutable**: Yes (pays for account creation)
  * **Signer**: Yes
</ParamField>

<ParamField path="system_program" type="Program<System>" required>
  The Solana system program.
</ParamField>

## Default Configuration

The instruction initializes the following default values:

* **Merkle Tree Height**: 26 levels (67,108,864 maximum commitments)
* **Root History Size**: 100 historical roots
* **Max Deposit Amount**: 1,000 SOL (1,000,000,000,000 lamports)
* **Deposit Fee Rate**: 0% (free deposits)
* **Withdrawal Fee Rate**: 0.25% (25 basis points)
* **Fee Error Margin**: 5% (500 basis points)

## Code Example

```typescript theme={null}
import * as anchor from "@coral-xyz/anchor";
import { Program } from "@coral-xyz/anchor";
import { PublicKey } from "@solana/web3.js";

const program = anchor.workspace.Zkcash as Program<Zkcash>;
const authority = anchor.web3.Keypair.generate();

// Derive PDAs
const [treeAccountPDA] = PublicKey.findProgramAddressSync(
  [Buffer.from("merkle_tree")],
  program.programId
);

const [treeTokenAccountPDA] = PublicKey.findProgramAddressSync(
  [Buffer.from("tree_token")],
  program.programId
);

const [globalConfigPDA] = PublicKey.findProgramAddressSync(
  [Buffer.from("global_config")],
  program.programId
);

// Initialize the program
await program.methods
  .initialize()
  .accounts({
    treeAccount: treeAccountPDA,
    treeTokenAccount: treeTokenAccountPDA,
    globalConfig: globalConfigPDA,
    authority: authority.publicKey,
    systemProgram: anchor.web3.SystemProgram.programId
  })
  .signers([authority])
  .rpc();

console.log("Privacy Cash initialized successfully");
```

## State Changes

### MerkleTreeAccount

* `authority`: Set to the signer's public key
* `next_index`: Initialized to 0
* `root_index`: Initialized to 0
* `max_deposit_amount`: Set to 1,000,000,000,000 lamports
* `height`: Set to 26
* `root_history_size`: Set to 100
* `bump`: PDA bump seed
* `root`: Initialized to the empty tree root

### TreeTokenAccount

* `authority`: Set to the signer's public key
* `bump`: PDA bump seed

### GlobalConfig

* `authority`: Set to the signer's public key
* `deposit_fee_rate`: Set to 0 (0% - free deposits)
* `withdrawal_fee_rate`: Set to 25 (0.25%)
* `fee_error_margin`: Set to 500 (5%)
* `bump`: PDA bump seed

## Authorization

<Tabs>
  <Tab title="Localnet">
    No authorization required. Any account can initialize.
  </Tab>

  <Tab title="Devnet">
    Must be called by: `97rSMQUukMDjA7PYErccyx7ZxbHvSDaeXp2ig5BwSrTf`
  </Tab>

  <Tab title="Mainnet">
    Must be called by: `AWexibGxNFKTa1b5R5MN4PJr9HWnWRwf8EW9g8cLx3dM`
  </Tab>
</Tabs>

## Errors

<ResponseField name="Unauthorized" type="Error">
  Thrown when the signer is not the authorized admin (mainnet/devnet only).
</ResponseField>

## See Also

* [initialize\_spl\_tree](/reference/instructions/initialize-spl-tree) - Initialize a tree for SPL tokens
* [update\_global\_config](/reference/instructions/update-global-config) - Update fee configuration
* [update\_deposit\_limit](/reference/instructions/update-deposit-limit) - Update deposit limits