Confidential Token Wrapper

A Rust CLI tool for wrapping any SPL token into confidential tokens using Solana's Token-2022 program with confidential transfer extensions.

Overview

This wrapper allows you to:

• Take any existing SPL token and wrap it into a confidential version
• Transfer the confidential tokens privately (amounts are encrypted)
• Unwrap confidential tokens back to the original SPL tokens

Prerequisites

• Rust toolchain installed
• Solana CLI installed and configured
• A Solana wallet with SOL for transaction fees
• Access to Solana devnet/mainnet

Installation

1. Clone the repository:

git clone https://github.com/deepakA18/Confidential-Transfer
cd confidential-transfer

2. Build the project:

cargo build --release

Configuration

The CLI uses your default Solana wallet located at ~/.config/solana/id.json. Make sure you have:

• A configured Solana wallet
• Sufficient SOL for transaction fees
• Some SPL tokens to wrap (for testing)

Usage

1. Initialize Wrapper

Create a confidential wrapper for any SPL token:

cargo run --bin wrapper_example -- init --mint <SPL_TOKEN_MINT_ADDRESS>

Example:

cargo run --bin wrapper_example -- init --mint ApxaHZoparjZFytE7Cxkp8meSybtmpXvgPjBzUpLdtki

2. Wrap Tokens

Convert SPL tokens to confidential tokens:

cargo run --bin wrapper_example -- wrap --mint <SPL_TOKEN_MINT_ADDRESS> --amount <AMOUNT>

Example:

cargo run --bin wrapper_example -- wrap --mint ApxaHZoparjZFytE7Cxkp8meSybtmpXvgPjBzUpLdtki --amount 10

3. Check Wrapper Information

View details about the wrapper:

cargo run --bin wrapper_example -- info --mint <SPL_TOKEN_MINT_ADDRESS>

4. Unwrap Tokens

Convert confidential tokens back to SPL tokens:

cargo run --bin wrapper_example -- unwrap --mint <SPL_TOKEN_MINT_ADDRESS> --amount <AMOUNT> --confidential-account <CONFIDENTIAL_ACCOUNT_ADDRESS>

Example:

cargo run --bin wrapper_example -- unwrap --mint ApxaHZoparjZFytE7Cxkp8meSybtmpXvgPjBzUpLdtki --amount 5 --confidential-account 75ZupPZEyuU1vsZDkTjp1Lpfmh5ySZAodBfv5Viu3uCU

5. Utility Commands

Check account balance:

cargo run --bin wrapper_example -- balance --account <ACCOUNT_ADDRESS>

Fund an account with SOL:

cargo run --bin wrapper_example -- fund --account <ACCOUNT_ADDRESS> --amount 1.0

How It Works

Wrapping Process

1. User deposits original SPL tokens into a secure vault
2. Equivalent confidential wrapper tokens are minted using Token-2022
3. Tokens are moved to confidential balance using encryption
4. User receives confidential tokens with encrypted amounts

Unwrapping Process

1. Confidential tokens are withdrawn from encrypted balance to public balance
2. Wrapper tokens are burned
3. Original SPL tokens are released from vault back to user

Security Features

• Deterministic wrapper mints: Same wrapper mint generated for same original token
• Secure vault system: Original tokens locked until unwrapping
• Zero-knowledge proofs: Transactions proven valid without revealing amounts
• ElGamal + AES encryption: Private keys unique to each user

Command Line Options

• --rpc-url: Solana RPC endpoint (default: https://api.devnet.solana.com)
• --keypair-path: Path to keypair file (default: ~/.config/solana/id.json)
• --verbose: Enable debug logging

Examples

Complete workflow with USDC on devnet:

# 1. Initialize wrapper for USDC
cargo run --bin wrapper_example -- init --mint 4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU

# 2. Wrap 100 USDC tokens
cargo run --bin wrapper_example -- wrap --mint 4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU --amount 100

# 3. Check wrapper status
cargo run --bin wrapper_example -- info --mint 4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU

# 4. Unwrap 50 USDC tokens back
cargo run --bin wrapper_example -- unwrap --mint 4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU --amount 50 --confidential-account <YOUR_CONFIDENTIAL_ACCOUNT>

Project Structure

src/
├── lib.rs              # Main library exports and types
├── wrapper.rs          # Core confidential wrapper implementation
├── utils.rs            # Utility functions
├── main.rs             # Original confidential transfer demo
└── bin/
    └── wrapper_example.rs  # CLI application

Dependencies

Key dependencies include:

• solana-sdk: Solana blockchain interaction
• spl-token: SPL token operations
• spl-token-2022: Token-2022 program with extensions
• spl-token-client: High-level token client
• Confidential transfer proof libraries
• clap: Command line argument parsing

Troubleshooting

"Invalid Mint" Error: Ensure the wrapper is initialized before wrapping tokens.

"Insufficient Balance" Error: Make sure you have enough of the original SPL tokens and SOL for transaction fees.

"Account Not Found" Error: The specified mint address or account doesn't exist.

Transaction Failures: Check your SOL balance and network connectivity.