保留残高を適用する
保留残高を利用可能残高に適用する方法
トークンを機密性を持って送金する前に、公開トークン残高を機密残高に変換する必要があります。この変換は2段階で行われます:
- 機密保留残高:最初に、トークンは公開残高から「機密保留」残高に「預け入れ」されます。
- 機密利用可能残高:その後、保留残高が利用可能残高に「適用」され、トークンが機密送金に利用できるようになります。
このセクションでは、2番目の段階について説明します:保留残高を利用可能残高に適用する方法です。
トークンが公開残高から「預け入れ」される場合や、あるtoken accountから別のtoken accountに機密送金される場合、トークンは最初に機密保留残高に追加されます。機密送金にトークンを使用する前に、保留残高を利用可能残高に「適用」する必要があります。
以下の図は、保留残高を利用可能残高に適用するステップを示しています:
必要な命令
保留残高を利用可能残高に変換するには、ConfidentialTransferInstruction::ApplyPendingBalance命令を呼び出します。
spl_token_client
クレートは、以下の例で示すように、ApplyPendingBalance
命令を含むトランザクションを構築して送信する
confidential_transfer_apply_pending_balance
メソッドを提供しています。
サンプルコード
以下の例は、機密保留残高を機密利用可能残高に適用する方法を示しています。
この例を実行するには、以下のコマンドを使用して、メインネットからクローンしたToken Extensions Programでローカルバリデータを起動します。ローカルバリデータを起動するには、Solana CLIがインストールされている必要があります。
$solana-test-validator --clone-upgradeable-program TokenzQdBNbLqP5VEhdkAS6EPFLC1PHnBqCXEpPxuEb --url https://api.mainnet-beta.solana.com -r
執筆時点では、機密転送はデフォルトのローカルvalidatorで有効になっていません。サンプルコードを実行するには、メインネットのToken Extensions Programをクローンする必要があります。
use anyhow::{Context, Result};use solana_client::nonblocking::rpc_client::RpcClient;use solana_sdk::{commitment_config::CommitmentConfig,signature::{Keypair, Signer},transaction::Transaction,};use spl_associated_token_account::{get_associated_token_address_with_program_id, instruction::create_associated_token_account,};use spl_token_client::{client::{ProgramRpcClient, ProgramRpcClientSendTransaction},spl_token_2022::{extension::{confidential_transfer::instruction::{configure_account, PubkeyValidityProofData},ExtensionType,},id as token_2022_program_id,instruction::reallocate,solana_zk_sdk::encryption::{auth_encryption::*, elgamal::*},},token::{ExtensionInitializationParams, Token},};use spl_token_confidential_transfer_proof_extraction::instruction::{ProofData, ProofLocation};use std::sync::Arc;#[tokio::main]async fn main() -> Result<()> {// Create connection to local test validatorlet rpc_client = Arc::new(RpcClient::new_with_commitment(String::from("http://localhost:8899"),CommitmentConfig::confirmed(),));// Load the default Solana CLI keypair to use as the fee payer// This will be the wallet paying for the transaction fees// Use Arc to prevent multiple clones of the keypairlet payer = Arc::new(load_keypair()?);println!("Using payer: {}", payer.pubkey());// Generate a new keypair to use as the address of the token mintlet mint = Keypair::new();println!("Mint keypair generated: {}", mint.pubkey());// Set up program client for Token clientlet program_client = ProgramRpcClient::new(rpc_client.clone(), ProgramRpcClientSendTransaction);// Number of decimals for the mintlet decimals = 9;// Create a token client for the Token-2022 program// This provides high-level methods for token operationslet token = Token::new(Arc::new(program_client),&token_2022_program_id(), // Use the Token-2022 program (newer version with extensions)&mint.pubkey(), // Address of the new token mintSome(decimals), // Number of decimal placespayer.clone(), // Fee payer for transactions);// Create extension initialization parameters for the mint// The ConfidentialTransferMint extension enables confidential (private) transfers of tokenslet extension_initialization_params =vec![ExtensionInitializationParams::ConfidentialTransferMint {authority: Some(payer.pubkey()), // Authority that can modify confidential transfer settingsauto_approve_new_accounts: true, // Automatically approve new confidential accountsauditor_elgamal_pubkey: None, // Optional auditor ElGamal public key}];// Create and initialize the mint with the ConfidentialTransferMint extension// This sends a transaction to create the new token mintlet transaction_signature = token.create_mint(&payer.pubkey(), // Mint authority - can mint new tokensSome(&payer.pubkey()), // Freeze authority - can freeze token accountsextension_initialization_params, // Add the ConfidentialTransferMint extension&[&mint], // Mint keypair needed as signer).await?;// Print results for user verificationprintln!("Mint Address: {}", mint.pubkey());println!("Mint Creation Transaction Signature: {}",transaction_signature);// ===== Create and configure token account for confidential transfers =====println!("\nCreate and configure token account for confidential transfers");// Get the associated token account address for the ownerlet token_account_pubkey = get_associated_token_address_with_program_id(&payer.pubkey(), // Token account owner&mint.pubkey(), // Mint&token_2022_program_id(), // Token program ID);println!("Token Account Address: {}", token_account_pubkey);// Step 1: Create the associated token accountlet create_associated_token_account_instruction = create_associated_token_account(&payer.pubkey(), // Funding account&payer.pubkey(), // Token account owner&mint.pubkey(), // Mint&token_2022_program_id(), // Token program ID);// Step 2: Reallocate the token account to include space for the ConfidentialTransferAccount extensionlet reallocate_instruction = reallocate(&token_2022_program_id(), // Token program ID&token_account_pubkey, // Token account&payer.pubkey(), // Payer&payer.pubkey(), // Token account owner&[&payer.pubkey()], // Signers&[ExtensionType::ConfidentialTransferAccount], // Extension to reallocate space for)?;// Step 3: Generate the ElGamal keypair and AES key for token accountlet elgamal_keypair = ElGamalKeypair::new_from_signer(&payer, &token_account_pubkey.to_bytes()).expect("Failed to create ElGamal keypair");let aes_key = AeKey::new_from_signer(&payer, &token_account_pubkey.to_bytes()).expect("Failed to create AES key");// The maximum number of Deposit and Transfer instructions that can// credit pending_balance before the ApplyPendingBalance instruction is executedlet maximum_pending_balance_credit_counter = 65536;// Initial token balance is 0let decryptable_balance = aes_key.encrypt(0);// Generate the proof data client-sidelet proof_data = PubkeyValidityProofData::new(&elgamal_keypair).map_err(|_| anyhow::anyhow!("Failed to generate proof data"))?;// Indicate that proof is included in the same transactionlet proof_location =ProofLocation::InstructionOffset(1.try_into()?, ProofData::InstructionData(&proof_data));// Step 4: Create instructions to configure the account for confidential transferslet configure_account_instructions = configure_account(&token_2022_program_id(), // Program ID&token_account_pubkey, // Token account&mint.pubkey(), // Mint&decryptable_balance.into(), // Initial balancemaximum_pending_balance_credit_counter, // Maximum pending balance credit counter&payer.pubkey(), // Token Account Owner&[], // Additional signersproof_location, // Proof location)?;// Combine all instructionslet mut instructions = vec![create_associated_token_account_instruction,reallocate_instruction,];instructions.extend(configure_account_instructions);// Create and send the transactionlet recent_blockhash = rpc_client.get_latest_blockhash().await?;let transaction = Transaction::new_signed_with_payer(&instructions,Some(&payer.pubkey()),&[&payer],recent_blockhash,);let transaction_signature = rpc_client.send_and_confirm_transaction(&transaction).await?;println!("Create Token Account Transaction Signature: {}",transaction_signature);// Mint some tokens to the newly created token account// This gives the account some tokens to work withlet mint_signature = token.mint_to(&token_account_pubkey, // Destination account&payer.pubkey(), // Mint authority100 * 10u64.pow(decimals as u32), // Amount (100 tokens with decimal precision)&[&payer], // Signers).await?;println!("Mint Tokens Transaction Signature: {}", mint_signature);// Deposit the tokens to confidential state// This converts regular tokens to confidential tokensprintln!("Deposit tokens to confidential state pending balance");let deposit_signature = token.confidential_transfer_deposit(&token_account_pubkey, // The token account&payer.pubkey(), // Authority (owner) of the account100 * 10u64.pow(decimals as u32), // Amount to deposit (100 tokens)decimals, // Decimals of the token&[&payer], // Signers (owner must sign)).await?;println!("Confidential Transfer Deposit Signature: {}",deposit_signature);// Apply the pending balance to make funds availableprintln!("Apply pending balance to available balance");let apply_signature = token.confidential_transfer_apply_pending_balance(&token_account_pubkey, // The token account&payer.pubkey(), // Authority (owner) of the accountNone, // Optional new decryptable available balanceelgamal_keypair.secret(), // ElGamal keypair for public-key cryptography (decryption and ZK proofs)&aes_key, // AES key for encryption of balance and transfer amounts&[&payer], // Signers (owner must sign)).await?;println!("Apply Pending Balance Signature: {}", apply_signature);println!("Confidential transfer setup complete. Tokens are now in available balance.");println!("Associated Token Account with confidential transfers: {}",token_account_pubkey);Ok(())}// Load the keypair from the default Solana CLI keypair path (~/.config/solana/id.json)// This enables using the same wallet as the Solana CLI toolsfn load_keypair() -> Result<Keypair> {// Get the default keypair pathlet keypair_path = dirs::home_dir().context("Could not find home directory")?.join(".config/solana/id.json");// Read the keypair file directly into bytes using serde_json// The keypair file is a JSON array of byteslet file = std::fs::File::open(&keypair_path)?;let keypair_bytes: Vec<u8> = serde_json::from_reader(file)?;// Create keypair from the loaded bytes// This converts the byte array into a keypairlet keypair = Keypair::from_bytes(&keypair_bytes)?;Ok(keypair)}
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