> ## Documentation Index
> Fetch the complete documentation index at: https://www.helius.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Transfer
> Guide to transfer SOL, SPL, or Token 2022 assets between private balances with a full code example.
1. A private transfer moves tokens in a ring between private wallets.
2. Private transfers are sent in a single Solana transaction to a Solana wallet address.
#### Transfer: What Is Private
| Field | Visibility | Why |
| --------------------- | ---------- | -------------------------------------------------------------------- |
| Asset | Private | The asset is encrypted onchain |
| Amount | Private | The transferred amount is encrypted onchain |
| Source private wallet | Public | In a confidential Ring the source private wallet is visible onchain. |
| Recipient | Public | In a confidential Ring the recipient is visible onchain. |
Transfers from and within a ring reveal the program ID of the custom Ring.
A balance in a Custom Ring can exit to an SPL token account, to the Default Ring, or to another Ring, as long as the source Ring's policy permits it.
The default Ring is permissionless and does not have a policy or authority.
One transaction can combine balances from the Default Ring and one Custom Ring. A transfer between two Custom Rings routes through the Default Ring.
| Private transfer | Custom confidential Rings | Custom anonymous Rings | Default confidential to or from Custom confidential | Confidential (Default or Custom) to Custom anonymous | Custom anonymous to confidential (Default or Custom) |
| ---------------------- | ------------------------- | ----------------------------------------------------------------------------------------------------------- | --------------------------------------------------- | ---------------------------------------------------- | ----------------------------------------------------------------------------------------------------------- |
| Amount | Private | Private | Private | Private | Private |
| Asset | Private | Private | Private | Private | Private |
| Source private wallet | Public | Private. A relayer submits the transaction, so the public ledger does not reveal the source private wallet. | Public | Public | Private. A relayer submits the transaction, so the public ledger does not reveal the source private wallet. |
| Recipient | Public | Private | Public | Private | Public |
| Custom Ring program ID | Public | Public | Public | Public | Public |
The permissionless Ring is confidential with encrypted amount and asset.
A custom Ring can be configured as confidential or anonymous (encrypted sender, recipient, asset, and amount).
## How a Transfer Works
A private transfer behaves similarly to a public Solana transfer:
1. The user's SOL or SPL balance is encrypted onchain.
2. The user decrypts private state, the wallet builds a transfer, and the owner signs.
* Fetch encrypted state with dedicated RPC methods. Only the user can decrypt balances locally.
* The wallet sets amount and recipient, then requests a ZK proof. The RPC provider generates the ZK proof by default and returns it.
3. The Solana runtime verifies the signatures and invokes the Solana Privacy Program, which verifies the ZK proof without revealing the encrypted state.
4. The app tracks status via the Solana transaction hash.
```mermaid theme={"system"}
%%{init: {
'theme': 'base',
'themeVariables': {
'lineColor': '#FF6B35',
'primaryTextColor': '#737373',
'primaryBorderColor': '#9CA3AF',
'actorBkg': '#FFFFFF',
'actorBorder': '#9CA3AF',
'actorTextColor': '#737373',
'signalColor': '#FF6B35',
'signalTextColor': '#737373',
'labelBoxBkgColor': '#FF6B351F',
'labelBoxBorderColor': '#FF6B35',
'noteBkgColor': '#F5F5F5',
'noteTextColor': '#737373',
'noteBorderColor': '#9CA3AF'
}
}}%%
sequenceDiagram
participant Wallet
participant RPC as RPC Provider
participant Solana
Wallet->>RPC: Fetch encrypted state
RPC-->>Wallet: Encrypted state
Note over Wallet: Decrypt
Note over Wallet: Set amount and recipient
Wallet->>RPC: Request ZK proof
Note over RPC: Generate ZK proof
RPC-->>Wallet: ZK proof
Note over Wallet: Build transaction, sign
Wallet->>RPC: Submit Transaction
RPC->>Solana: Forward transaction
Note over Solana: Verify signatures
Note over Solana: CPI Solana Privacy Program
Note over Solana: Verify ZK proof
RPC-->>Wallet: Transaction signature
```
1. The user's SOL or SPL balance is public onchain.
2. The wallet reads public state, builds a transfer, and the owner signs.
3. The Solana runtime verifies the signatures and invokes the System Program or Token Program, which updates the public balance.
4. The app tracks status via the Solana transaction hash.
```mermaid theme={"system"}
%%{init: {
'theme': 'base',
'themeVariables': {
'lineColor': '#FF6B35',
'primaryTextColor': '#737373',
'primaryBorderColor': '#9CA3AF',
'actorBkg': '#FFFFFF',
'actorBorder': '#9CA3AF',
'actorTextColor': '#737373',
'signalColor': '#FF6B35',
'signalTextColor': '#737373',
'labelBoxBkgColor': '#FF6B351F',
'labelBoxBorderColor': '#FF6B35',
'noteBkgColor': '#F5F5F5',
'noteTextColor': '#737373',
'noteBorderColor': '#9CA3AF'
}
}}%%
sequenceDiagram
participant Wallet
participant RPC
participant Solana
Wallet->>RPC: Get public balance
RPC-->>Wallet: Public state
Note over Wallet: Build transfer, owner signs
Wallet->>RPC: sendTransaction
RPC->>Solana: Forward transaction
Note over Solana: Verify signatures
Note over Solana: CPI System / Token Program
Note over Solana: Update balance
RPC-->>Wallet: Transaction signature
```
This is the high-level transaction flow for the permissionless confidential Ring.
Compare to custom Rings in [concepts](/docs/privacy/concepts#high-level-transaction-flow).
# Get Started
### Prerequisites
The TypeScript examples require Node.js 24 or later, pnpm 11.18.0, and the Solana CLI.
```bash theme={"system"}
pnpm add @heliuslabs/zolana @solana/kit
```
Source: [sdk-libs/ts](https://github.com/helius-labs/zolana/tree/main/sdk-libs/ts)
```bash theme={"system"}
pnpm install
cp .env.example .env
```
Add a [Helius API key](https://dashboard.helius.dev/):
```bash .env theme={"system"}
API_KEY=YOUR_API_KEY
ZOLANA_PAYER_KEYPAIR=~/.config/solana/id.json
```
```ts theme={"system"}
import { createZolanaClient } from "@heliuslabs/zolana";
const client = await createZolanaClient({
solanaRpcUrl: "https://devnet.helius-rpc.com/?api-key=YOUR_API_KEY",
indexerUrl: "http://zolnet-devnet-1779374825.eu-north-1.elb.amazonaws.com",
proverUrl: "http://zolnet-devnet-1779374825.eu-north-1.elb.amazonaws.com:3001",
allowInsecureHttp: true,
});
```
The examples use the Solana CLI wallet as the payer by default. The payer must hold devnet SOL. See [How to Get Devnet SOL](/docs/rpc/devnet-sol).
On localnet the SDK starts the local test validator (`:8899`), Photon indexer (`:8784`), and prover (`:3001`), and the
client connects to them automatically without needing endpoint configuration.
```bash theme={"system"}
cargo install --git https://github.com/helius-labs/zolana --tag v0.1.0-alpha zolana-cli
zolana dev start
```
```ts theme={"system"}
import { createZolanaClient } from "@heliuslabs/zolana";
const client = await createZolanaClient({});
```
### Transfer to a Private Balance
```typescript theme={"system"}
import {
appendTransactionMessageInstructions,
assertIsTransactionWithBlockhashLifetime,
createTransactionMessage,
getSignatureFromTransaction,
pipe,
sendTransactionWithoutConfirmingFactory,
setTransactionMessageFeePayerSigner,
setTransactionMessageLifetimeUsingBlockhash,
signTransactionMessageWithSigners,
type Instruction,
type Signature,
type TransactionSigner,
} from "@solana/kit";
import { createZolanaClient } from "@heliuslabs/zolana";
type Client = Awaited>;
export interface ConfirmedTransaction {
readonly signature: Signature;
readonly slot: bigint;
}
export function sendAndConfirmFactory(
client: Client,
feePayer: TransactionSigner,
): (instructions: readonly Instruction[]) => Promise {
const sendTransaction = sendTransactionWithoutConfirmingFactory({
rpc: client.solanaRpc,
});
return async function sendAndConfirm(
instructions: readonly Instruction[],
): Promise {
const { value: lifetime } = await client.solanaRpc
.getLatestBlockhash()
.send();
const signed = await signTransactionMessageWithSigners(
pipe(
createTransactionMessage({ version: 0 }),
(message) => setTransactionMessageFeePayerSigner(feePayer, message),
(message) =>
setTransactionMessageLifetimeUsingBlockhash(lifetime, message),
(message) =>
appendTransactionMessageInstructions(instructions, message),
),
);
assertIsTransactionWithBlockhashLifetime(signed);
await sendTransaction(signed, { commitment: "confirmed" });
const signature = getSignatureFromTransaction(signed);
const slot = await client.confirmTransaction(signature);
return { signature, slot };
};
}
```
* The SDK returns instructions. The app signs and sends them.
* `sendAndConfirmFactory` builds a Kit transaction, submits it, and returns the signature plus the landed slot.
```typescript theme={"system"}
import { SOL_MINT } from "@heliuslabs/zolana";
import { transactInstruction } from "@heliuslabs/zolana/interface";
import {
ConfidentialTransfer,
ProofInputUtxo,
} from "@heliuslabs/zolana/transaction";
import { sendAndConfirmFactory } from "../src/lib.js";
const sendAndConfirm = sendAndConfirmFactory(
client,
senderSigner,
);
const transferUtxo = depositBalance.utxos[0]!;
const transferInput =
ProofInputUtxo.fromKeypair(
transferUtxo,
senderKeypair,
);
const transfer = new ConfidentialTransfer(
senderAddress,
[transferInput],
senderSigner.address,
);
transfer.send(
recipient,
SOL_MINT,
TRANSFER_AMOUNT,
);
const transferProofInputs = transfer.sign(
senderKeypair,
assets,
);
const transferData = await client.proveTransact(
transferProofInputs,
);
const transferInstruction = transactInstruction(
{
payer: senderSigner,
inputTree: client.tree,
outputTree: client.tree,
data: transferData,
},
);
const transferTx = await sendAndConfirm([
transferInstruction,
]);
```
```typescript theme={"system"}
import { transactInstruction } from "@heliuslabs/zolana/interface";
import {
ConfidentialTransfer,
ProofInputUtxo,
} from "@heliuslabs/zolana/transaction";
import { sendAndConfirmFactory } from "../src/lib.js";
const sendAndConfirm = sendAndConfirmFactory(
client,
senderSigner,
);
const transferUtxo = depositBalance.utxos[0]!;
const transferInput =
ProofInputUtxo.fromKeypair(
transferUtxo,
senderKeypair,
);
const transfer = new ConfidentialTransfer(
senderAddress,
[transferInput],
senderSigner.address,
);
transfer.send(
recipient,
spl.mint,
TRANSFER_AMOUNT,
);
const transferProofInputs = transfer.sign(
senderKeypair,
assets,
);
const transferData = await client.proveTransact(
transferProofInputs,
);
const transferInstruction = transactInstruction(
{
payer: senderSigner,
inputTree: client.tree,
outputTree: client.tree,
data: transferData,
},
);
const transferTx = await sendAndConfirm([
transferInstruction,
]);
```
```typescript theme={"system"}
import { SOL_MINT } from "@heliuslabs/zolana";
const transferUtxo = depositBalance.utxos[0]!;
```
* The example spends the Private Solana Token Account created by the preceding deposit. A transfer can spend multiple UTXOs.
* `transferUtxo` selects one Private Solana Token Account from that balance.
```typescript theme={"system"}
import { ProofInputUtxo } from "@heliuslabs/zolana/transaction";
const transferInput =
ProofInputUtxo.fromKeypair(
transferUtxo,
senderKeypair,
);
```
* `ProofInputUtxo.fromKeypair` prepares the selected UTXO as a proof input with the sender's private wallet keypair.
* The keypair derives the nullifier that marks the input UTXO as spent while the asset and amount remain encrypted.
```typescript theme={"system"}
import { SOL_MINT } from "@heliuslabs/zolana";
import { ConfidentialTransfer } from "@heliuslabs/zolana/transaction";
const transfer = new ConfidentialTransfer(
senderAddress,
[transferInput],
senderSigner.address,
);
transfer.send(
recipient,
SOL_MINT,
TRANSFER_AMOUNT,
);
const transferProofInputs = transfer.sign(
senderKeypair,
assets,
);
```
* `senderAddress` is the sender's Shielded Address. The transfer spends from this wallet.
* `[transferInput]` lists the sender's selected UTXOs. A transfer can spend multiple UTXOs.
* `senderSigner.address` is the fee payer's Solana address. A gas sponsor can fill this role for a confidential transfer.
* `recipient` is the recipient's Shielded Address. The transferred output is encrypted to the recipient's viewing key.
* `SOL_MINT` selects SOL. An SPL or Token 2022 transfer passes the token mint.
* `TRANSFER_AMOUNT` is denominated in the asset's base units. SOL uses lamports. SPL and Token 2022 assets use the token's base units.
* `transfer.sign` authorizes the state transition, encrypts the asset and amount, and produces the inputs for the zero-knowledge prover.
* `assets` is the asset registry used to resolve supported private assets.
```typescript theme={"system"}
import { createZolanaClient } from "@heliuslabs/zolana";
const transferData = await client.proveTransact(
transferProofInputs,
);
```
* `client.proveTransact` generates the zero-knowledge proof from the signed transfer and returns serialized instruction data.
* The proof demonstrates that the sender owns and can spend the inputs without revealing the encrypted asset or amount.
```typescript theme={"system"}
import { transactInstruction } from "@heliuslabs/zolana/interface";
const transferInstruction = transactInstruction(
{
payer: senderSigner,
inputTree: client.tree,
outputTree: client.tree,
data: transferData,
},
);
```
* `payer` signs and pays for the Solana transaction. A gas sponsor can fill this role for a confidential transfer.
* `inputTree` and `outputTree` are `client.tree`, the state Merkle tree that contains the spent UTXOs and receives the recipient output and sender change.
* `data` contains the zero-knowledge proof and encrypted outputs produced in the previous step.
* A private transfer moves the asset only between private balances. It does not pass public Solana accounts or token accounts.
```typescript theme={"system"}
import { sendAndConfirmFactory } from "../src/lib.js";
const transferTx = await sendAndConfirm([
transferInstruction,
]);
```
* `sendAndConfirm` signs and submits `transferInstruction` as a Solana transaction.
* Confirmation yields the landed slot used to gate the indexer fetch.
### Full Code Example
Clone and run the example:
```bash theme={"system"}
git clone https://github.com/helius-labs/zolana-examples.git
cd zolana-examples/typescript-client
pnpm install
pnpm example examples/deposit_transfer_withdraw.ts
```
The examples use a confidential Ring on local/devnet [here](https://github.com/helius-labs/zolana-examples/blob/main/typescript-client/examples/deposit_transfer_withdraw.ts).
```typescript deposit_transfer_withdraw.ts expandable theme={"system"}
import {
SOL_MINT,
createZolanaClient,
} from "@heliuslabs/zolana";
import { atSlot } from "@heliuslabs/zolana/client";
import {
depositInstruction,
transactInstruction,
DepositAsset,
TransactWithdrawal,
} from "@heliuslabs/zolana/interface";
import { randomBlinding } from "@heliuslabs/zolana/keypair";
import {
AssetRegistry,
ConfidentialTransfer,
ProofInputUtxo,
decryptToBalances,
WithdrawalTarget,
} from "@heliuslabs/zolana/transaction";
import {
sendAndConfirmFactory,
setup,
} from "../src/lib.js";
const DEPOSIT_AMOUNT = 1_000_000_000n;
const TRANSFER_AMOUNT = 300_000_000n;
const WITHDRAW_AMOUNT = 300_000_000n;
async function main(): Promise {
const {
sender: senderKeypair,
recipient: recipientKeypair,
clientConfig,
} = await setup();
// Connect to Helius devnet RPC plus the Photon indexer and prover.
const client =
await createZolanaClient(clientConfig);
// Initialize the sender's private wallet and local authority
// to decrypt transactions and sync balances.
// The Solana signer and private wallet are derived from the same Ed25519 seed.
const senderSigner =
senderKeypair.toSolanaSigner();
const senderAddress =
senderKeypair.shieldedAddress();
const recipient =
recipientKeypair.shieldedAddress();
// The SDK hands back instructions; the app owns signing and sending.
const sendAndConfirm = sendAndConfirmFactory(
client,
senderSigner,
);
// Mints that are registered with Solana Rings for privacy.
const assets = new AssetRegistry();
// Deposit SOL into the sender's private balance.
// A deposit from a public balance reveals
// sender, recipient, asset and amount.
// Alternatively, you can onramp fiat directly to a private balance.
// 1. Move public SOL into the sender's private balance.
// The view tag is the sender's Solana public key in confidential rings.
// Used by the indexer to fetch the sender's UTXOs.
const senderViewTag =
senderAddress.confidentialViewTag();
const depositIx = await depositInstruction({
tree: client.tree,
depositor: senderSigner,
deposits: [
{
asset: DepositAsset.sol(),
viewTag: senderViewTag,
recipientOwnerHash:
senderAddress.ownerHash(),
blinding: randomBlinding(),
amount: DEPOSIT_AMOUNT,
},
],
});
// 2. Send and confirm like any Solana transaction; confirmation yields the landed slot.
const depositTx = await sendAndConfirm([
depositIx,
]);
// 3. Fetch transaction outputs from the indexer, gated on the deposit's slot.
// The indexer returns encrypted outputs by view tag.
const depositResponse =
await client.getShieldedTransactionsByTags(
{ tags: [senderViewTag] },
atSlot(depositTx.slot),
);
// 4. The sender decrypts the transaction outputs locally to read the private balance.
const balancesAfterDeposit =
await decryptToBalances({
keypair: senderKeypair,
registry: assets,
transactions: depositResponse.transactions,
});
const depositBalance =
balancesAfterDeposit.balance(SOL_MINT);
if (depositBalance.amount !== DEPOSIT_AMOUNT) {
throw new Error(
`expected deposit amount ${DEPOSIT_AMOUNT}, got ${depositBalance.amount}`,
);
}
if (depositBalance.utxos.length !== 1) {
throw new Error(
`expected 1 deposit utxo, got ${depositBalance.utxos.length}`,
);
}
// Confidential SOL transfer to the recipient's private balance.
// A confidential transfer reveals only sender and recipient,
// not the asset or amount.
// 1. Select private token accounts (UTXOs) that make up the private balance for the transfer.
const transferUtxo = depositBalance.utxos[0]!;
// 2. Prepare the selected UTXOs as inputs for the zero-knowledge proof.
const transferInput =
ProofInputUtxo.fromKeypair(
transferUtxo,
senderKeypair,
);
// 3. Build and sign the confidential transfer.
// Signing encrypts the asset and amount and produces the proof inputs for the ZK prover.
const transfer = new ConfidentialTransfer(
senderAddress,
[transferInput],
senderSigner.address,
);
transfer.send(
recipient,
SOL_MINT,
TRANSFER_AMOUNT,
);
const transferProofInputs = transfer.sign(
senderKeypair,
assets,
);
// 4. Fetch the ZK proof to prove the sender can spend the balance without revealing asset and amount.
const transferData = await client.proveTransact(
transferProofInputs,
);
// 5. Build the instruction with the state Merkle tree and Solana accounts required for the transfer.
// Private transfers move balances only between private token accounts, not public token accounts.
const transferInstruction = transactInstruction(
{
payer: senderSigner,
inputTree: client.tree,
outputTree: client.tree,
data: transferData,
},
);
// 6. Send and confirm like any Solana transaction; confirmation yields the landed slot.
const transferTx = await sendAndConfirm([
transferInstruction,
]);
// 7. Fetch the sender's UTXOs again, gated on the transfer's slot,
// and read the remaining private balance.
const transferResponse =
await client.getShieldedTransactionsByTags(
{ tags: [senderViewTag] },
atSlot(transferTx.slot),
);
const balancesAfterTransfer =
await decryptToBalances({
keypair: senderKeypair,
registry: assets,
transactions: transferResponse.transactions,
});
const transferBalance =
balancesAfterTransfer.balance(SOL_MINT);
if (
transferBalance.amount !==
DEPOSIT_AMOUNT - TRANSFER_AMOUNT
) {
throw new Error(
`expected remaining amount ${DEPOSIT_AMOUNT - TRANSFER_AMOUNT}, got ${transferBalance.amount}`,
);
}
if (transferBalance.utxos.length !== 1) {
throw new Error(
`expected 1 transfer utxo, got ${transferBalance.utxos.length}`,
);
}
// Withdraw SOL from the sender's private balance to their public balance.
// A withdrawal reveals the sender, recipient, asset, and amount.
// 1. Select private token accounts (UTXOs) that make up the private balance for the withdrawal.
const withdrawalUtxo =
transferBalance.utxos[0]!;
// 2. Prepare the selected UTXOs as inputs for the zero-knowledge proof.
const withdrawalInput =
ProofInputUtxo.fromKeypair(
withdrawalUtxo,
senderKeypair,
);
// 3. Build and sign the private-to-public withdrawal.
// Signing encrypts the asset and amount of the remaining private balance
// and produces the proof inputs for the ZK prover.
const withdrawal = new ConfidentialTransfer(
senderAddress,
[withdrawalInput],
senderSigner.address,
);
withdrawal.withdraw(
SOL_MINT,
WITHDRAW_AMOUNT,
WithdrawalTarget.sol({
recipient: senderSigner.address,
}),
);
const withdrawalProofInputs = withdrawal.sign(
senderKeypair,
assets,
);
// 4. Fetch the ZK proof to prove the sender can spend the balance.
const withdrawalData =
await client.proveTransact(
withdrawalProofInputs,
);
// 5. Build the instruction with the state Merkle tree and Solana accounts required for the withdrawal.
const withdrawalInstruction =
transactInstruction({
payer: senderSigner,
inputTree: client.tree,
outputTree: client.tree,
withdrawal: TransactWithdrawal.sol({
recipient: senderSigner.address,
}),
data: withdrawalData,
});
// 6. Send and confirm like any Solana transaction; confirmation yields the landed slot.
const withdrawalTx = await sendAndConfirm([
withdrawalInstruction,
]);
// 7. Fetch the sender's UTXOs again, gated on the withdrawal's slot,
// and read the remaining private balance.
const withdrawalResponse =
await client.getShieldedTransactionsByTags(
{ tags: [senderViewTag] },
atSlot(withdrawalTx.slot),
);
const balancesAfterWithdrawal =
await decryptToBalances({
keypair: senderKeypair,
registry: assets,
transactions:
withdrawalResponse.transactions,
});
const withdrawalBalance =
balancesAfterWithdrawal.balance(SOL_MINT);
if (
withdrawalBalance.amount !==
DEPOSIT_AMOUNT -
TRANSFER_AMOUNT -
WITHDRAW_AMOUNT
) {
throw new Error(
`expected remaining amount ${DEPOSIT_AMOUNT - TRANSFER_AMOUNT - WITHDRAW_AMOUNT}, got ${withdrawalBalance.amount}`,
);
}
if (withdrawalBalance.utxos.length !== 1) {
throw new Error(
`expected 1 withdrawal utxo, got ${withdrawalBalance.utxos.length}`,
);
}
// 8. Read remaining private balance and the public balance.
const solanaBalance = await client.getBalance(
senderSigner.address,
);
console.log(
`withdraw private_balance=${withdrawalBalance.amount} ` +
`solana_balance=${solanaBalance} tx=${withdrawalTx.signature}`,
);
}
await main();
```
### Prerequisites
The Rust examples require the latest stable Rust toolchain and the Solana CLI v4.0.2. See the [Solana installation guide](https://solana.com/docs/intro/installation).
```toml Cargo.toml theme={"system"}
[dependencies]
zolana-client = { git = "https://github.com/helius-labs/zolana", tag = "v0.1.0-alpha", features = ["indexer-api", "solana-rpc"] }
zolana-interface = { git = "https://github.com/helius-labs/zolana", tag = "v0.1.0-alpha", features = ["solana"] }
zolana-keypair = { git = "https://github.com/helius-labs/zolana", tag = "v0.1.0-alpha" }
zolana-transaction = { git = "https://github.com/helius-labs/zolana", tag = "v0.1.0-alpha" }
```
Source: [sdk-libs/client](https://github.com/helius-labs/zolana/tree/v0.1.0-alpha/sdk-libs/client)
Add a [Helius API key](https://dashboard.helius.dev/):
```bash .env theme={"system"}
API_KEY=YOUR_API_KEY
ZOLANA_PAYER_KEYPAIR=~/.config/solana/id.json
```
```rust theme={"system"}
use solana_address::Address;
use zolana_client::{SolanaRpc, ZolanaClient};
use zolana_interface::DEFAULT_TREE_ADDRESS;
let tree: Address = DEFAULT_TREE_ADDRESS.parse()?;
let client = ZolanaClient::from_urls_allowing_insecure_http(
SolanaRpc::new("https://devnet.helius-rpc.com/?api-key=YOUR_API_KEY"),
"http://zolnet-devnet-1779374825.eu-north-1.elb.amazonaws.com",
"http://zolnet-devnet-1779374825.eu-north-1.elb.amazonaws.com:3001",
tree,
);
```
The examples use the Solana CLI wallet as the payer by default. The payer must hold devnet SOL. See [How to Get Devnet SOL](/docs/rpc/devnet-sol).
```bash theme={"system"}
cargo install --git https://github.com/helius-labs/zolana --tag v0.1.0-alpha zolana-cli
zolana dev start
```
```rust theme={"system"}
use solana_address::Address;
use zolana_client::{SolanaRpc, ZolanaClient};
use zolana_interface::DEFAULT_TREE_ADDRESS;
let tree: Address = DEFAULT_TREE_ADDRESS.parse()?;
let client = ZolanaClient::from_urls(
SolanaRpc::new("http://127.0.0.1:8899"),
"http://127.0.0.1:8784",
"http://127.0.0.1:3001",
tree,
)?;
```
### Transfer to a Private Balance
```rust theme={"system"}
use zolana_interface::instruction::Transact;
use zolana_transaction::{
instructions::{
transact::ConfidentialTransfer,
types::SppProofInputUtxo,
},
SOL_MINT,
};
let transfer_utxo = sender_balances_after_deposit
.get_balance(SOL_MINT)
// SPL: .get_balance(spl.mint)
.and_then(|balance| balance.utxos.first())
.expect("failed to fetch deposited utxo")
.clone();
let transfer_input_utxo = SppProofInputUtxo::new(transfer_utxo, &sender);
let mut transfer = ConfidentialTransfer::new(
sender_shielded_address,
vec![transfer_input_utxo],
sender_solana_keypair.pubkey(),
);
transfer.send(&recipient_address, SOL_MINT, TRANSFER_AMOUNT)?;
// SPL: transfer.send(&recipient_address, spl.mint, TRANSFER_AMOUNT)?;
let proof_inputs = transfer.sign(&sender, &assets)?;
let transfer_data = client.prove_transact(tree, proof_inputs, None)?;
let transfer_ix = Transact {
payer: sender_solana_keypair.pubkey(),
input_tree: tree,
output_tree: tree,
owner_signers: Vec::new(),
interface_transfer_accounts: Vec::new(),
data: transfer_data,
}
.instruction();
```
```rust theme={"system"}
use zolana_transaction::SOL_MINT;
let transfer_utxo = sender_balances_after_deposit
.get_balance(SOL_MINT)
// SPL: .get_balance(spl.mint)
.and_then(|balance| balance.utxos.first())
.expect("failed to fetch deposited utxo")
.clone();
```
* The example spends the Private Solana Token Account created by the preceding deposit. A transfer can spend multiple UTXOs.
* `transfer_utxo` is the first spendable UTXO for that asset. The `// SPL:` comment shows `get_balance(spl.mint)`.
```rust theme={"system"}
use zolana_transaction::instructions::types::SppProofInputUtxo;
let transfer_input_utxo = SppProofInputUtxo::new(transfer_utxo, &sender);
```
* `SppProofInputUtxo::new` prepares the selected UTXO as a proof input with the sender's private wallet keypair.
* The keypair derives the nullifier that marks the input UTXO as spent while the asset and amount remain encrypted.
```rust theme={"system"}
use zolana_transaction::{
instructions::transact::ConfidentialTransfer,
SOL_MINT,
};
let mut transfer = ConfidentialTransfer::new(
sender_shielded_address,
vec![transfer_input_utxo],
sender_solana_keypair.pubkey(),
);
transfer.send(&recipient_address, SOL_MINT, TRANSFER_AMOUNT)?;
// SPL: transfer.send(&recipient_address, spl.mint, TRANSFER_AMOUNT)?;
let proof_inputs = transfer.sign(&sender, &assets)?;
```
* `sender_shielded_address` is the sender's Shielded Address. The transfer spends from this wallet.
* `vec![transfer_input_utxo]` lists the sender's selected UTXOs. A transfer can spend multiple UTXOs.
* `sender_solana_keypair.pubkey()` is the transaction fee payer. A gas sponsor can fill this role for a confidential transfer.
* `recipient_address` is the recipient's Shielded Address. The transferred output is encrypted to the recipient's viewing key.
* `SOL_MINT` selects SOL. The `// SPL:` comment shows the token mint for SPL and Token 2022 assets.
* `TRANSFER_AMOUNT` is denominated in the asset's base units. SOL uses lamports. SPL and Token 2022 assets use the token's base units.
* `transfer.sign` authorizes the state transition, encrypts the asset and amount, and produces the inputs for the zero-knowledge prover.
* `assets` is the asset registry used to resolve supported private assets.
```rust theme={"system"}
use zolana_client::Rpc;
let transfer_data = client.prove_transact(tree, proof_inputs, None)?;
```
* `client.prove_transact` generates the zero-knowledge proof from the signed transfer and returns serialized instruction data.
* `tree` identifies the state Merkle tree whose root is used to prove input UTXO membership.
* The proof demonstrates that the sender owns and can spend the inputs without revealing the encrypted asset or amount.
```rust theme={"system"}
use zolana_interface::instruction::Transact;
let transfer_ix = Transact {
payer: sender_solana_keypair.pubkey(),
input_tree: tree,
output_tree: tree,
owner_signers: Vec::new(),
interface_transfer_accounts: Vec::new(),
data: transfer_data,
}
.instruction();
```
* `payer` signs and pays for the Solana transaction. A gas sponsor can fill this role for a confidential transfer.
* `input_tree` identifies the state Merkle tree that contains the spent UTXOs.
* `output_tree` identifies the state Merkle tree that receives commitments to the recipient output and sender change.
* `interface_transfer_accounts` is empty because a private transfer moves the asset only between private balances and does not interact with public balances in Solana accounts or token accounts.
* `owner_signers` is empty for this confidential transfer.
* `data` contains the zero-knowledge proof and encrypted outputs produced in the previous step.
```rust theme={"system"}
use zolana_client::Rpc;
let signature = client.create_and_send_transaction(
&[transfer_ix],
sender_solana_keypair.pubkey(),
&[&sender_solana_keypair],
)?;
let slot = landed_slot(&client, signature)?;
```
* `create_and_send_transaction` signs and submits `transfer_ix` as a Solana transaction.
* `landed_slot` reads the confirmation slot used to gate the indexer fetch.
* `sender_solana_keypair` pays the fee and authorizes the transfer.
## Full Code Example
Clone and run the example:
```bash theme={"system"}
git clone https://github.com/helius-labs/zolana-examples.git
cd zolana-examples/rust-client
cargo run -p rust-client-example --example deposit_transfer_withdraw
```
The examples use a confidential Ring on local/devnet [here](https://github.com/helius-labs/zolana-examples/blob/main/rust-client/examples/deposit_transfer_withdraw.rs).
```rust deposit_transfer_withdraw.rs expandable theme={"system"}
use anyhow::{anyhow, Result};
use rust_client_example::{setup, SetupContext};
use solana_signature::Signature;
use solana_signer::Signer;
use zolana_client::{IndexerRpcConfig, Rpc, SolanaRpc, ZolanaClient};
use zolana_interface::instruction::{
AssetDeposit, Deposit, DepositAsset, Transact, TransactInterfaceTransferAccounts,
TransactSolTransferAccounts,
};
use zolana_keypair::random_blinding;
use zolana_transaction::{
decrypt_transactions,
instructions::{
transact::{ConfidentialTransfer, SettlementTarget},
types::SppProofInputUtxo,
},
AssetRegistry, SOL_MINT,
};
const DEPOSIT_AMOUNT: u64 = 1_000_000_000;
const TRANSFER_AMOUNT: u64 = 300_000_000;
const WITHDRAW_AMOUNT: u64 = 300_000_000;
fn main() -> Result<()> {
let SetupContext {
rpc_url,
indexer_url,
prover_url,
tree,
sender,
recipient_address,
} = setup()?;
// Load the funded fee payer and devnet settings, then connect.
// Photon and the prover are HTTP on this ALB, so the constructor permits that.
let client = ZolanaClient::from_urls_allowing_insecure_http(
SolanaRpc::new(rpc_url),
&indexer_url,
prover_url,
tree,
);
// Mints that are registered with Solana Rings for privacy.
let assets = AssetRegistry::default();
// SPL: assets.insert(spl.asset_id, spl.mint)?;
// Initialize the sender's private wallet and local authority
// to decrypt transactions and sync balances.
// The Solana signer and private wallet are derived from the same Ed25519 seed.
let sender_solana_keypair = sender.to_solana_keypair()?;
let sender_shielded_address = sender.shielded_address()?;
// Deposit SOL into the sender's private balance.
// A deposit from a public balance reveals
// sender, recipient, asset and amount.
// Alternatively, you can onramp fiat directly to a private balance.
// 1. Move public SOL into the sender's private balance.
let sender_balances_after_deposit = {
let deposit_ix = Deposit {
tree,
depositor: sender_solana_keypair.pubkey(),
deposits: vec![AssetDeposit {
asset: DepositAsset::Sol,
// SPL: asset: DepositAsset::Spl(zolana_interface::instruction::DepositSplAccounts {
// SPL: mint: spl.mint,
// SPL: user_token: spl.user_token_account,
// SPL: token_program: spl.token_program,
// SPL: }),
view_tag: sender_shielded_address.confidential_view_tag()?,
owner: sender_shielded_address.owner_hash()?,
blinding: random_blinding(),
amount: DEPOSIT_AMOUNT,
utxo_data: None,
memo: None,
}],
}
.instruction()?;
// 2. Send and confirm like any Solana transaction; the landed slot gates
// the indexer fetch below.
let signature = client.create_and_send_transaction(
&[deposit_ix],
sender_solana_keypair.pubkey(),
&[&sender_solana_keypair],
)?;
let slot = landed_slot(&client, signature)?;
// 3. Fetch transaction outputs from the indexer, gated on the deposit's slot.
// The indexer returns encrypted outputs by view tag, the sender's public key in Confidential Rings.
let sender_tag = sender_shielded_address.confidential_view_tag()?;
let response = client.get_shielded_transactions_by_tags(
vec![sender_tag],
None,
Some(50),
Some(IndexerRpcConfig::at_slot(slot)),
)?;
// 4. The sender decrypts the transaction outputs locally to update the private balance.
let balances = decrypt_transactions(&sender, &response.transactions, &assets)
.map_err(|e| anyhow!("decrypt sender transactions: {e:?}"))?;
let sender_balance = balances
.get_balance(SOL_MINT)
// SPL: .get_balance(spl.mint)
.expect("failed to fetch sender's utxo");
assert_eq!(sender_balance.amount, DEPOSIT_AMOUNT);
assert_eq!(sender_balance.utxos.len(), 1);
balances
};
// Confidential SOL transfer to the recipient's private balance.
// A confidential transfer reveals only sender and recipient,
// not the asset or amount.
let sender_balances_after_transfer = {
// 1. Select UTXOs that make up the private balance for the transfer.
let transfer_utxo = sender_balances_after_deposit
.get_balance(SOL_MINT)
// SPL: .get_balance(spl.mint)
.and_then(|balance| balance.utxos.first())
.expect("failed to fetch deposited utxo")
.clone();
// 2. Prepare the selected UTXOs as inputs for the zero-knowledge proof.
let transfer_input_utxo = SppProofInputUtxo::new(transfer_utxo, &sender);
// 3. Build and sign the confidential transfer.
// Signing encrypts the asset and amount and produces the proof inputs for the ZK prover.
let mut transfer = ConfidentialTransfer::new(
sender_shielded_address,
vec![transfer_input_utxo],
sender_solana_keypair.pubkey(),
);
transfer.send(&recipient_address, SOL_MINT, TRANSFER_AMOUNT)?;
// SPL: transfer.send(&recipient_address, spl.mint, TRANSFER_AMOUNT)?;
let proof_inputs = transfer.sign(&sender, &assets)?;
// 4. Fetch the zk proof to prove the sender can spend the balance without revealing asset and amount.
let transfer_data = client.prove_transact(tree, proof_inputs, None)?;
// 5. Construct the instruction.
let transfer_ix = Transact {
payer: sender_solana_keypair.pubkey(),
input_tree: tree,
output_tree: tree,
owner_signers: Vec::new(),
interface_transfer_accounts: Vec::new(),
data: transfer_data,
}
.instruction();
// 6. Send and confirm like any Solana transaction; confirmation yields the landed slot.
let signature = client.create_and_send_transaction(
&[transfer_ix],
sender_solana_keypair.pubkey(),
&[&sender_solana_keypair],
)?;
let slot = landed_slot(&client, signature)?;
// 7. Sync the sender's wallet, gated on the transfer's slot, and read
// the remaining private balance.
let sender_tag = sender_shielded_address.confidential_view_tag()?;
let response = client.get_shielded_transactions_by_tags(
vec![sender_tag],
None,
Some(50),
Some(IndexerRpcConfig::at_slot(slot)),
)?;
let sender_balances = decrypt_transactions(&sender, &response.transactions, &assets)
.map_err(|e| anyhow!("decrypt sender transactions: {e:?}"))?;
let sender_balance = sender_balances
.get_balance(SOL_MINT)
// SPL: .get_balance(spl.mint)
.expect("failed to fetch sender's utxo");
assert_eq!(sender_balance.amount, DEPOSIT_AMOUNT - TRANSFER_AMOUNT);
assert_eq!(sender_balance.utxos.len(), 1);
sender_balances
};
// Withdraw SOL back to the sender's public balance.
// A withdrawal from a confidential balance reveals
// sender, recipient, asset and amount.
{
// 1. Select UTXOs that make up the private balance for the withdrawal.
let withdrawal_utxo = sender_balances_after_transfer
.get_balance(SOL_MINT)
// SPL: .get_balance(spl.mint)
.and_then(|balance| balance.utxos.first())
.expect("failed to fetch sender's utxo")
.clone();
// 2. Prepare the selected UTXOs as inputs for the zero-knowledge proof.
let withdrawal_input_utxo = SppProofInputUtxo::new(withdrawal_utxo, &sender);
// 3. Build and sign the confidential withdrawal.
// Signing encrypts the private change and produces the ZK prover inputs.
let mut withdrawal = ConfidentialTransfer::new(
sender_shielded_address,
vec![withdrawal_input_utxo],
sender_solana_keypair.pubkey(),
);
withdrawal.withdraw(
SOL_MINT,
WITHDRAW_AMOUNT,
SettlementTarget::Sol {
user_sol_account: sender_solana_keypair.pubkey(),
},
)?;
// SPL: withdrawal.withdraw(
// SPL: spl.mint,
// SPL: WITHDRAW_AMOUNT,
// SPL: SettlementTarget::Spl {
// SPL: user_spl_token: spl.user_token_account,
// SPL: spl_token_interface: spl.vault,
// SPL: },
// SPL: )?;
let proof_inputs = withdrawal.sign(&sender, &assets)?;
// 4. Fetch the ZK proof to prove the sender can spend the balance.
let withdrawal_data = client.prove_transact(tree, proof_inputs, None)?;
// 5. Combine the proof and withdrawal accounts in a single instruction.
let withdraw_ix = Transact {
payer: sender_solana_keypair.pubkey(),
input_tree: tree,
output_tree: tree,
owner_signers: Vec::new(),
interface_transfer_accounts: vec![TransactInterfaceTransferAccounts::Sol(
TransactSolTransferAccounts {
recipient: sender_solana_keypair.pubkey(),
},
)],
// SPL: interface_transfer_accounts: vec![
// SPL: TransactInterfaceTransferAccounts::SplWithdrawal(
// SPL: zolana_interface::instruction::TransactSplWithdrawalAccounts {
// SPL: mint: spl.mint,
// SPL: vault: spl.vault,
// SPL: user_token_account: spl.user_token_account,
// SPL: token_program: spl.token_program,
// SPL: },
// SPL: ),
// SPL: ],
data: withdrawal_data,
}
.instruction();
// 6. Send and confirm like any Solana transaction.
let signature = client.create_and_send_transaction(
&[withdraw_ix],
sender_solana_keypair.pubkey(),
&[&sender_solana_keypair],
)?;
let slot = landed_slot(&client, signature)?;
// 7. Sync the sender's wallet, gated on the withdrawal's slot, and read
// the remaining private balance.
let sender_tag = sender_shielded_address.confidential_view_tag()?;
let response = client.get_shielded_transactions_by_tags(
vec![sender_tag],
None,
Some(50),
Some(IndexerRpcConfig::at_slot(slot)),
)?;
let sender_balances = decrypt_transactions(&sender, &response.transactions, &assets)
.map_err(|e| anyhow!("decrypt sender transactions: {e:?}"))?;
let sender_balance = sender_balances
.get_balance(SOL_MINT)
// SPL: .get_balance(spl.mint)
.expect("failed to fetch sender's utxo");
assert_eq!(
sender_balance.amount,
DEPOSIT_AMOUNT - TRANSFER_AMOUNT - WITHDRAW_AMOUNT
);
assert_eq!(sender_balance.utxos.len(), 1);
// 8. Read remaining private balance and the public SOL balance.
let solana_balance = client.get_balance(sender_solana_keypair.pubkey())?;
println!("withdraw solana_balance={solana_balance} tx={signature}");
// SPL: println!(
// SPL: "withdraw user_token={} tx={signature}",
// SPL: spl.user_token_account,
// SPL: );
}
Ok(())
}
/// Slot the confirmed transaction landed in, which drives the indexer
/// freshness gate on the fetches that read the transaction back.
fn landed_slot(client: &ZolanaClient, signature: Signature) -> Result {
client
.get_signature_statuses(vec![signature])?
.first()
.and_then(|status| status.as_ref())
.map(|status| status.slot)
.ok_or_else(|| anyhow!("transaction status missing after confirmation"))
}
```
## Related Guides
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