Onyx SDK

Privacy-preserving stealth addresses for Solana.

Onyx SDK enables private payments on Solana using stealth addresses. Senders can transfer SOL to unique one-time addresses that only the intended recipient can detect and spend from, without revealing the recipient's identity on-chain.

Features

• Stealth Addresses - Generate unique one-time addresses for each payment
• Unlinkable Payments - Observers cannot connect payments to your public identity
• Efficient Scanning - On-chain registry for payment detection
• Ed25519 Compatible - Works with Solana's native key format
• Anchor Program - Ready-to-deploy on-chain announcement registry

Installation

Add to your Cargo.toml:

[dependencies]
onyx-sdk = "0.1"

Or install via cargo:

cargo add onyx-sdk

Quick Start

Receiver: Generate a Stealth Meta-Address

use onyx_sdk::prelude::*;

// Generate new stealth meta-address
let meta = StealthMetaAddress::generate();

// Share this publicly to receive payments
let public_meta = meta.to_public();
println!("My stealth address: {}", public_meta.encode());

// Save privately (contains spending key!)
meta.save_to_file("~/.onyx/keys.json")?;

Sender: Create a Stealth Payment

use onyx_sdk::prelude::*;

// Parse receiver's public meta-address
let public_meta = PublicMetaAddress::decode("st:sol:...")?;

// Create stealth payment
let payment = StealthPayment::create(&public_meta)?;

println!("Send SOL to: {}", payment.stealth_address);
println!("Ephemeral key: {}", hex::encode(&payment.ephemeral_pubkey));

// Transfer SOL to payment.stealth_address
// Publish payment.ephemeral_pubkey to the registry

Receiver: Detect and Spend

use onyx_sdk::prelude::*;

// Load your meta-address
let meta = StealthMetaAddress::load_from_file("~/.onyx/keys.json")?;

// Check if a payment is for you
if let Some(_) = meta.try_detect(&ephemeral_pubkey)? {
    // Derive the keypair to spend
    let keypair = StealthKeypair::derive(&meta, &ephemeral_pubkey)?;

    // Use keypair.to_solana_keypair() to sign transactions
    println!("Can spend from: {}", keypair.address());
}

How It Works

1. Receiver generates a stealth meta-address (spending + viewing keypairs) and shares the public portion
2. Sender uses the meta-address to derive a unique stealth address and ephemeral keypair
3. Sender transfers SOL to the stealth address and publishes the ephemeral public key
4. Receiver scans ephemeral keys, detects payments meant for them, and derives the spending key

The cryptographic scheme uses ECDH (Elliptic Curve Diffie-Hellman) to create shared secrets that allow the receiver to derive the same stealth address and spending key that the sender generated.

Project Structure

onyx-sdk/
├── crates/
│   ├── core/       # Main SDK library (onyx-sdk)
│   └── program/    # Anchor program (onyx-program)
└── cli/            # Command-line interface (onyx)

CLI Usage

# Install
cargo install --path cli

# Generate new stealth meta-address
onyx init

# Show your public meta-address
onyx address

# Send SOL to a stealth address
onyx send <recipient-meta-address> <amount>

# Check balance
onyx balance <address>

Anchor Program

The onyx-program provides an on-chain registry for stealth payment announcements:

• initialize - Create the announcement registry (PDA)
• send_stealth - Transfer SOL + register announcement in one transaction
• announce - Register an announcement without transfer

Security

• Private keys are never transmitted or stored on-chain
• Viewing keys allow detection without spending capability
• Spending keys are derived deterministically from the shared secret
• Uses SHA-256 for key derivation with domain separation

License

MIT OR Apache-2.0